Tag Archives: AHSCT

Detail, DMTsDetail, Treatment strategy

What are the attributes of the specific DMTs?

Multiple sclerosis (MS) treatment has evolved rapidly, with 11 classes of disease-modifying therapy (DMT) now available in the UK. I will summarise them briefly and explain how they fit within a treatment paradigm for effective and safe use.

Maintenance therapies versus immune reconstitution: what’s the difference?

There is a divide between the two main treatment philosophies: maintenance ̶ escalation versus immune reconstitution therapies (IRTs).

An IRT is given as a short course – a one-off treatment in the case of autologous haematopoietic stem cell transplantation (AHSCT) or intermittently for alemtuzumab, cladribine or mitoxantrone. IRTs are not given continuously, and additional courses are given only if inflammatory activity recurs. IRTs can induce long-term remission and, in some cases, potentially a cure.

Maintenance therapies, by comparison, are given continuously without an interruption in dosing (‘continuous’ administration may be daily, one or more times weekly, monthly or even once every few months). Although maintenance therapies can induce long-term remission, they cannot, by definition, result in a cure. The recurrence or continuation of inflammatory activity indicates a suboptimal response to treatment and typically requires a treatment switch. Ideally, this switch should be an escalation to a more effective class of DMT.

An article in our list of key questions, entitled How do I want my MS to be treated?, provides a more detailed comparison of maintenance and IRT therapies, including frequency of administration, efficacy, risks, use in pregnancy, vaccine response and potential for a cure.

The DMTs currently licensed in the UK (in August 2024) are listed in the table under the relevant category.

table format updated 180625 SS

Disease-modifying therapies for MS licensed in the UK. *Please note, Bonspri is available in other markets but not the UK.

How effective are the different DMTs?

The measures used to assess the effectiveness of a DMT include its ability to reduce or prevent relapses, focal inflammatory activity (that is, new or enlarging lesions) on magnetic resonance imaging (MRI), and disability progression. Additional factors that can help to assess the relative efficacy of DMTs include the proportion of clinical trial subjects who experience improvement in disability and the impact of the treatment on brain volume loss.

The MS-Selfie InfoCards are an easy-to-use resource to help people with MS compare the key features of each DMT. They contain bite-sized information designed to aid treatment choices and an overview of the key aspects of each DMT.

Efficacy of the licensed DMTs for MS can be visualised as pyramid, with the moderately effective treatments at the bottom and the more effective approaches at the top. What determines the most appropriate DMT efficacy level for an individual depends on several factors, such as baseline prognostic profile, family planning requirements, local or national treatment guidelines, socioeconomic factors, consideration of any co-existing illnesses, cognitive impairment, risk aversion and lifestyle issues.

Pyramid format updated 180625 SS

UK licensed DMTs for MS, in ascending order of efficacy.
HSCT/AHSCT, haematopoietic stem cell transplantation/autologous haematopoietic stem cell transplantation.

What is the goal of treatment? Introducing NEIDA as a target

In the past, we used no evident disease activity (NEDA) as a treatment target. ‘Disease activity’ included progression or disease worsening independent of relapse activity (termed smouldering MS). Although some of the more effective DMTs may modify this stage of the disease, many neurologists feel uncomfortable switching or stopping a DMT based simply on smouldering MS disease activity. 

Relapses and ongoing focal MRI activity are associated with a worse short-term to intermediate-term prognosis. These observations have led to the increasing adoption of ‘no evident inflammatory disease activity’ (NEIDA) as a new treatment target. For more information about treatment targets, please see the article in our key questions, Do I understand the concepts of treat-2-target and NEDA?

Many healthcare professionals (HCPs) remain sceptical of using NEIDA as a treatment target, fearing that this could lead to more people with MS being on ‘riskier’ high-efficacy therapies. However, achieving long-term remission, or NEIDA, is a well-established treatment target in other autoimmune diseases such as rheumatoid arthritis and inflammatory bowel disease. People with MS treated-to-target of NEIDA from the outset do better than those whose treatment is escalated following breakthrough disease (at a clinical or subclinical/MRI level)1. I would, therefore, strongly encourage people with MS and their HCPs to adopt NEIDA as an initial treatment target.

Flipping the pyramid

The effectiveness, or relative effectiveness, of individual DMTs becomes less critical in the context of a treatment target of NEIDA. Choosing a DMT with a lower efficacy rate simply means that a greater proportion of treated people with MS will need to be switched to higher efficacy therapies over time to achieve NEIDA. We refer to the latter of these three approaches – starting with high-efficacy treatment – as flipping the pyramid. In recent trials of alemtuzumab, ocrelizumab, ofatumumab and ublituximab, people with MS randomised to 2 years of lower efficacy DMTs (interferon-beta-1a or teriflunomide) had poorer outcomes than those receiving highly active therapy from the outset. Real-world data from registries also support this; groups of people with MS with delayed access to high-efficacy DMTs did worse than those who received high-efficacy treatments early.1,2

Horizontal versus vertical switching

If we consider the conventional step care paradigm, people with MS who switch horizontally from interferon-beta to glatiramer acetate, or vice-versa (i.e. from one moderate efficacy DMT to another moderate efficacy DMT) do less well than those who switch vertically to fingolimod, a highly effective DMT. Similarly, people with MS escalating to natalizumab, a very high-efficacy DMT, do better than those being escalated to the less effective, but still high-efficacy, DMT fingolimod. 

Continuous and intermittent immunosuppression

Another useful way of classifying DMTs is whether they are immunosuppressive, that is, they reduce the activation, or effectiveness, of the immune system. Drug regulators stipulate that a drug may be classified as immunosuppressive if it (1) causes significant lymphopaenia (low lymphocyte count) or leukopenia (low white blood cell count), (2) is associated with opportunistic infections, (3) reduces the antibody and immune response to vaccines and (4) increases the risk of secondary malignancies.

The duration and intensity of immunosuppression further determine the risks. For example, short-term or intermittent immunosuppression associated with IRTs front-loads the risks, which are substantially lower once the immune system has reconstituted itself. In comparison, long-term continuous or persistent immunosuppression, which occurs with some of the maintenance DMTs, accumulates problems over time, particularly opportunistic infections and secondary malignancies. You can read more detail on this topic in the key question How immunosuppressed am I? The following table summarises the main attributes of intermittent and persistent immunosuppression.

How immunosuppressed are you table updated format 180625 SS

The main characteristics of continuous (persistent) and short-term (intermittent) immunosuppression. Modified from Giovannoni, Curr Opin Neurol.2
AHSCT, autologous haematopoietic stem cell transplantation; PML, progressive multifocal leukoencephalopathy.

Adverse effects, monitoring and risk reduction

The complications associated with immunosuppression vary from DMT to DMT. Each individual drug summary in the DMTs section of MS-Selfie contains detailed information about the main adverse events, key monitoring requirements, use (or contraindication) during pregnancy and breastfeeding, and response to vaccines. The MS-Selfie InfoCards provide bite-sized summaries of several practical aspects, including side effects, to enable easy comparison of any treatments you are considering; some of this information is collated below for easy reference.

Short-term versus long-term adverse effects

Each drug has been given scores from 1 to 10 based on published analyses of its short-term and long-term side effects. Short-term refers to side effects that emerge when a treatment is started and decrease in severity or disappear within days or weeks. A well-known example of short-term side effects on starting interferon-beta is flu-like symptoms that typically abate within 4 ̶ 8 weeks.

A long-term side effect persists for months or doesn’t disappear on continuing the DMT. Examples include intermittent but persistent flushing after taking dimethyl fumarate, or low B lymphocyte counts with anti-CD20 therapies that may lead to low antibody or immunoglobulin levels (hypogammaglobulinaemia).

A low score denotes few or rare side effects; a high score denotes many or frequent side effects. The score does not correlate to a percentage. More information can be found in each drug summary and the manufacturer’s Summary of Product Characteristics.

Scores for short-term and long-term side effects assigned to the individual DMTs summarised in the MS-Selfie InfoCards, based on a published network meta-analysis.3
Alem, alemtuzumab; GA, glatiramer acetate; HSCT, haematopoietic stem cell transplantation; IFN-beta; interferon-beta; Nat, natalizumab.

Monitoring and risk reduction

Numerous tests are carried out at the start of treatment, and ongoing monitoring is required for many factors, to reduce the risk from adverse events. The key question, How can I reduce my chances of adverse events on specific DMTs?, explains what needs to be done at the start of DMT administration (baseline) and during subsequent monitoring. The specifics vary from DMT to DMT; please refer to the individual summaries for details such as baseline tests, follow-up, infection prevention, cancer risk, pregnancy, breastfeeding and vaccination. It is important to remember that all licensed MS DMTs have had a thorough risk ̶ benefit assessment, and their benefits are considered to outweigh the potential risks.

Administration and other practical considerations

Routes and frequency of administration

The MS-Selfie InfoCards contain a symbol for each DMT, showing how it is administered. Some DMTs are available in more than one formulation (e.g. tablets and injection). The frequency of administration varies greatly from DMT to DMT; please consult the relevant summary in the DMTs section and discuss your preferences and priorities with your MS HCP.

The route of administration for each drug in the MS-Selfie InfoCards is clearly identified by the relevant symbol. (If a DMT is available in more than one formulation, there is a separate card for each delivery route.)

Number of clinic visits

It may be important for you to consider the frequency of clinic visits. This will depend on factors such as the delivery route of your DMT, the monitoring requirements of the drug regulators and the risk of specific side effects. The table below summarises the assessments from the MS-Selfie InfoCards. This is another factor to consider in discussions with your MS HCPs about the most appropriate DMT for you.

Conclusions

People with MS must understand the objectives of MS treatments and the different treatment strategies currently available to achieve these objectives. Although the MS therapeutic landscape is complex and hence may seem overwhelming, framing the choices using a relatively simple construct should help each individual to make informed decisions about managing their MS. MS-Selfie aims to guide you in the process of deciding on the most appropriate therapeutic strategy and specific DMT for treating your disease.

References

  1. Rotstein D, et al. Association of No Evidence of Disease Activity with no long-term disability progression in multiple sclerosis: a systematic review and meta-analysis. Neurology 2022;99:e209̶ ̶ 20.
  2. Giovannoni G. Disease-modifying treatments for early and advanced multiple sclerosis: a new treatment paradigm. Curr Opin Neurol 2018;31:233 ̶ 43.
  3. Samjoo IA, et al. Efficacy classification of modern therapies in multiple sclerosis. J Comp Eff Res 2021;10:495–507.
DMTsDetail

HSCT (haematopoietic stem cell transplant)

Summary

HSCT (haematopoietic stem cell transplant) is not a drug, it is a procedure that involves harvesting of stem cells that first need to be mobilised from the bone marrow using a ‘conditioning’ regimen of low-dose chemotherapy and growth factors. The stem cells are harvested from the blood and frozen down or stored. People with MS undergoing HSCT then have their immune system depleted with chemotherapy to a greater (myeloablative HSCT) or lesser extent (non-myeloablative HSCT). The stem cells are re-infused to allow more rapid recovery of bone marrow and immune function. HSCT is not a ‘licensed therapy’ for MS, but it is offered as a treatment for more active disease in many countries – typically for MS that has not responded to standard DMTs. HSCT is on the list of essential off-label DMTs because it is a generic procedure available in many countries. In other words, it can also be used for treating MS where access to high-cost licensed DMTs is limited. 

What is HSCT?

HSCT is simply a ‘rebranding’ of bone marrow transplantation (BMT). BMT refers to the harvesting of stem cells using a bone marrow aspirate, whereby a thick needle is inserted into the bone and the marrow is sucked out under pressure. This procedure is painful and is done under sedation. Haematologists have now developed an effective way of mobilising and harvesting stem cells from the blood without tapping the bone marrow. A small dose of chemotherapy is given, followed by growth factors so the stem cells spill over from the bone marrow into the blood. These stem cells are harvested and frozen and can then be given after chemotherapy (immunoablation therapy) has depleted your immune cells.

The introduction of the harvested stem cells speeds up bone marrow recovery after immune system ablation (depletion). More rapid bone marrow recovery makes BMT safer because you have less chance of getting a life-threatening infection or bleeding.

The stem cells in HSCT don’t go to the brain and spinal cord to repair the damage. This is a common misconception. Recovery of neurological function seen after HSCT is spontaneous endogenous repair, which we see with all the DMTs, particularly the highly effective treatments. Like other DMTs, HSCT is most effective when used early, before MS causes too much damage, or in younger people with MS (as we age, the nervous system’s ability to repair itself decreases).

Types of HSCT

There are different intensities of bone marrow ablation. So-called myeloablative therapy aims to wipe out your immune system entirely and replace it with a new immune system. Non-myeloablative therapy is less intense: it partially depletes your immune system and allows it to be rebooted (partially). Non-myeloablative therapy is less toxic and less risky than myeloablative therapy, but also less effective. A recurrence of disease activity is therefore more likely after non-myeloablative HSCT than after myeloablative–HSCT. 

Many in the field maintain that if you treat MS with HSCT you should use the more toxic and riskier myeloablative–HSCT. They argue that non-myeloablative–HSCT is no better than the high-efficacy drugs we already use, such as alemtuzumab, natalizumab and/or ocrelizumab. Trials are currently ongoing to compare alemtuzumab with non-myeloablative–HSCT and see if the potential benefits of non-myeloablative–HSCT warrant the risks.1,2,3

Non-myeloablative HSCT – risks

The chance of dying from non-myeloablative–HSCT is in the order of 0.3% ̶ 2%; i.e., a 1-in-330 risk to as high as 1-in-50. The toxicity associated with the chemotherapy is severe, including nausea, vomiting, diarrhoea, hair loss, bleeding, infections, infertility and neurotoxicity. It seems that the more disabled you are, the worse the neurotoxicity. If you have lost a lot of nerve fibres and have reduced brain reserve, the chemotherapy worsens neurological function. This is why many BMT units stopped using this therapy in people with more advanced MS and why most units have an upper Expanded Disability Status Scale (EDSS) score limit as part of their inclusion and exclusion criteria.

Does your immune system return to normal post-HSCT? There is evidence that HSCT may rejuvenate the immune system and change the so-called ‘repertoire’ (memory) of your B and T cells. We don’t yet know what it means for MS, but we do know that HSCT may destroy memory cells from your previous vaccinations. So, you may need to be revaccinated with all your childhood vaccines at ~2 years after HSCT to restore your immune responses to these common infections. 

What about secondary autoimmunity?

There are data to suggest that people with MS treated with both myeloablative–HSCT and non-myeloablative–HSCT are at risk of developing secondary autoimmune diseases similar to those that occur after alemtuzumab treatment. This risk is lower than that seen with alemtuzumab, but there is a definite signal. At present I find it challenging to recommend non-myeloablative–HSCT over alemtuzumab, unless it is part of a controlled trial or the patient has already failed alemtuzumab.

Myeloablative HSCT – risks

The short-term risks from the intense chemotherapy needed to ablate the immune system with myeloablative–HSCT are much worse than with non-myeloablative–HSCT. Everything is worse: the diarrhoea tends to be bloody and protracted; mucositis is the norm (the lining of your mouth, throat and intestine slough); infections are more severe and are potentially life-threatening; there is the potential for solid organ toxicity (liver, lungs, kidneys and heart); your bone marrow takes longer to recover, and as a result you are more likely to need platelet and blood transfusions. Myeloablative–HSCT is not for the faint-hearted. Many HSCT enthusiasts in the autoimmune field assert that myeloablative–HSCT is the way to go; the failure rate from non-myeloablative–HSCT is too high. They argue that if you are going to take the risk of having HSCT, you might as well go for maximum efficacy with myeloablative–HSCT.

The Lazarus effect

The seemingly miraculous treatment effects of people with MS in wheelchairs getting up and walking are not unique to HSCT. We see these ‘Lazarus effects’ with other highly effective DMTs. Provided you have sufficient reserve capacity in the brain (brain reserve) and spinal cord (neurological reserve) you will see spontaneous recovery from relapse-related disability once inflammation is switched off and recovery mechanisms can proceed. Tragically these Lazarus-like examples create unrealistic expectations for people with more advanced disease. Once you have a fixed or progressive disability, you have most likely lost your neurological reserve. Even if you switch off inflammation with HSCT or another anti-inflammatory DMT, any significant recovery of function is unlikely. Many progressive MS trials have failed because the benefit:risk ratio changes with more advanced disease. This is why most HSCT or BMT units have age and disability cut-offs for people with MS.

Would I refer patients for HSCT?

Yes, I do. HSCT is indicated as part of routine clinical care in the small number of patients with malignant MS who has already failed licensed treatment options. In such patients, the benefits of HSCT outweigh the risks of the disease. In practice, however, people with MS are concerned chiefly about the infertility risk from HSCT. The risk of premature ovarian failure, or early menopause, following chemotherapy is over 40%; this dissuades many women. Similarly, for men, cyclophosphamide (the chemotherapy) hits the testes hard, so if you want to start or extend your family after HSCT you will need to bank sperm.

Weighing the risks

Please remember the human brain is hard-wired to be optimistic. I like the analogy of the gambler’s dilemma. No gambler places a bet or goes into a casino to lose money; they believe they will win. No person will sign up to HSCT believing they will die or develop complications. However, inevitably some will be unlucky and have serious complications, delayed adverse events or even die from the procedure. If you decide to have HSCT as part of a trial or routine care, you need to ask yourself: What if I am the unlucky one? Am I ready to leave my family and loved ones prematurely? If you answer ‘yes’ to both questions, you are ready to take the risks. In the same way, I warn my patients who sign up for alemtuzumab treatment that they should expect to develop a secondary autoimmune complication; if they don’t, they should count themselves lucky. If they are not prepared to develop a second autoimmune disease, they shouldn’t be treated with alemtuzumab.

Mode of action

HSCT is an immune reconstitution therapy (IRT). It works by depleting your immune system and allowing it to reconstitute. The hope is that when the immune system has reconstituted, the autoimmune cells that cause MS are absent.

Efficacy

Very high.

Class

Non-selective IRT, short-term immunosuppression.

Immunosuppression

Yes, short-term, whilst the immune system is depleted. Once it reconstitutes itself, the immune system is competent.

Protocols

The following are some examples of HSCT protocols used to treat MS.

Low intensity (non-myeloablative)

  • Cyclophosphamide plus anti-thymocyte globulin.
  • Cyclophosphamide plus fludarabine phosphate.

Intermediate intensity (non-myeloablative)

  • BEAM – a combination of BiCNU/carmustine, etoposide, Ara-C/cytarabine and melphalan.
  • BEAM plus anti-thymocyte globulin.
  • Cyclophosphamide plus thiotepa.
  • Total lymphoid irradiation plus melphalan.
  • Carmustine plus cyclophosphamide plus anti-thymocyte globulin.

High intensity (myeloablative)

  • Cyclophosphamide plus total body irradiation plus anti-thymocyte globulin.
  • Busulfan plus cyclophosphamide plus anti-thymocyte globulin.
  • Busulfan plus anti-thymocyte globulin.

Adverse events and events of special interest

This is not a complete list of adverse events associated with HSCT. Please note some of the complications can be life-threatening.

Infection

During the first 6 weeks after HSCT, until the new stem cells start making white blood cells (engraftment), you can easily develop serious infections. Bacterial infections are most common, but viral infections that were controlled by your immune system can become active again. For example, cytomegalovirus (CMV) is a common cause of pneumonia in people who have had transplants and in people with MS who were already infected with CMV. Fungal infections can also be an issue. Even infections that cause only mild symptoms in people with normal immune systems can pose a danger. For instance, pneumocystis pneumonia (often called PCP) is easy to catch and can cause fever, cough, and serious breathing problems if your immune system is compromised. Antibiotics are often used to keep HSCT patients from getting this. You may be given antibiotics to try to prevent other infections until your blood counts reach a certain level.

While in the hospital, everyone who enters your room must wash their hands well. They may also wear gowns, shoe coverings, gloves, and masks. Since flowers and plants can carry bacteria and fungi, they are not allowed in your room. After engraftment, the risk of infection is lower, but it still can happen. It takes 3 months to one year after transplant for the immune system of most patients to work as well as it should. Because of the increased risk, you will continue to be watched closely for signs of infection, such as fever, cough, shortness of breath, or diarrhoea. Your doctor may check your blood often, and extra precautions will be needed to avoid exposure to germs. For the same reason, you may be told not to eat certain fresh fruits and vegetables. All your food must be well cooked and handled very carefully by you and family members. Certain foods may need to be avoided for a while. You will also be told to avoid contact with soil, faeces (both human and animal), aquariums, reptiles, and exotic pets. Your team may tell you to avoid being near disturbed soil, bird droppings, or mould. You need to wash your hands after touching pets. If you have a cat, you may need to remove the cat’s litter tray from where you eat or spend time.

Your transplant team will tell you and your family about the precautions you need to follow. Despite all these precautions, many patients develop fevers, one of the first signs of infection. If you do get a fever or other signs of infection, contact your doctor right away. Tests will be done to determine the cause of the infection (chest X-rays, urine tests, and blood cultures), and antibiotics will be started.

Nausea and vomiting

A common side effect from the chemotherapy given with HSCT, nausea and vomiting, is treated with antiemetics. No one drug can fully prevent or control chemotherapy-related nausea and vomiting; hence, combination therapies are often required.

Mouth and throat pain

Mucositis (inflammation or sores in the mouth) is a short-term side effect that happens with high-intensity chemotherapy. It usually gets better within a few weeks of treatment, but it can make eating and drinking painful.

Hair loss

Hair loss is likely during HSCT, typically beginning within 2 ̶ 3 weeks of treatment. However, hair growth will return to normal once the treatment is finished.

Bleeding and transfusions

After HSCT, you are at risk for bleeding because the conditioning treatment destroys your body’s ability to make platelets (the blood cells that help blood to clot.) While you wait for your transplanted stem cells to start working, you must take special precautions to avoid injury and bleeding. Platelet counts are typically low for at least 3 weeks after HSCT. During this time, you might notice easy bruising and bleeding, such as nosebleeds and bleeding gums. A platelet transfusion may be required if your platelet count drops below a certain level. It also takes time for your bone marrow to start making red blood cells. If you become too anaemic, you might require red blood cell transfusions.

Cardiotoxicity

High doses of chemotherapy used as part of HSCT can cause cardiotoxicity. This is most common in older people with MS and people who have received prior cardiotoxic drugs, for example, mitoxantrone.

Neurotoxicity

Both the central and peripheral nervous systems are susceptible to the toxic effects of chemotherapy used as part of the conditioning regimen in HSCT. People with more advanced MS and significant disability are particularly sensitive to chemotherapy-induced worsening of disability. The effects on the peripheral nervous system are mainly due to length-dependent neuropathy, with loss of feeling in the ends of the extremities. Neurotoxicity is rarely a problem with low- and intermediate-intensity chemotherapy regimens.

Interstitial pneumonitis and other lung problems

Pneumonitis is a type of lung inflammation most common in the first 100 days after HSCT. Pneumonia caused by infection happens more often, but pneumonitis may be caused by chemotherapy rather than germs. It results from damage to the areas between the cells of the lungs (the so-called interstitial spaces). Pneumonitis tends to occur only with more intensive conditioning regimens.

Hepatic veno-occlusive disease

Hepatic veno-occlusive disease is a serious problem in which tiny veins and other blood vessels inside the liver become blocked. It is very uncommon, and only happens in individuals who received the drugs busulfan or melphalan as part of their conditioning regimen and as part of allogeneic HSCT (from a donor) rather than autologous HSCT (AHSCT, i.e. from the patient).

Infertility

Many people with MS who have HSCT become infertile and cannot have children. This is not caused by the transplanted stem cells but rather by the high doses of chemotherapy and/or radiation therapy used to ablate the immune system. These treatments affect normal and abnormal cells and damage the reproductive organs. If having children is important to you, or if it might be important in the future, there are ways to protect your fertility. If indicated, women should be offered GnRH agonists as ovarian protection throughout therapy or the possibility of egg harvesting and storage. The risk of infertility depends on the specific conditioning regimen. After chemotherapy, women find their menstrual periods become irregular or stop completely (amenorrhea). This doesn’t always mean you cannot get pregnant, so birth control should still be used before and after HSCT.

The drugs used during HSCT can also damage sperm, so men should use birth control to avoid starting a pregnancy during and for some time after the HSCT process. HSCT may cause temporary or permanent infertility for men as well; it is worth considering storing sperm before having a transplant (this process can take several days). Fertility returns in some men, but the timing is unpredictable.

Secondary autoimmunity

People with MS treated with HSCT are at risk of developing secondary autoimmune diseases similar to those that occur after alemtuzumab treatment. The risk of secondary autoimmunity after HSCT is about 10%, which is lower than after alemtuzumab. Does this mean that you must participate in the same type of pharmacovigilance required by patients treated with alemtuzumab? I am not sure about this, but all the patients I have referred for HSCT who have come through the procedure successfully are not enrolled in an intensive pharmacovigilance programme. All study subjects in our current trial of alemtuzumab versus non-myeloablative–HSCT are undergoing monthly blood and urine monitoring, which should allow us to assess the current pharmacovigilance requirement.

Graft-versus-host disease (GVHD)

This adverse event is commonly reported on HSCT and BMT unit websites. It typically happens with allogeneic (donor) transplants when the immune cells from the donor see your body as foreign. Allogeneic transplants are not used to treat MS. Despite this, GVHD may occur with autologous HSCT if you receive a blood transfusion that contains live lymphocytes from the donor. The latter is prevented by irradiating all fresh blood products before administering them to HSCT patients. 

HSCT graft failure

Grafts fail when you have too few stem cells, either because the body does not accept them or they did not survive the mobilisation and storage procedure. In this case, we must wait for your bone marrow to recover spontaneously. Depending on the intensity of the conditioning regimen, this can take many weeks. During this period, you are very susceptible to infections and bleeding. Grafts rarely fail, but graft failure can result in death.

Secondary cancers caused by HSCT

There is a small chance of developing a secondary cancer after HSCT, which is caused by the chemotherapy damaging your cell’s DNA or the associated immunosuppression.

  • Lymphomas are most often associated with HSCT, especially the B cell types, which tend to be caused by Epstein-Barr virus (EBV). When the immune system is suppressed after HSCT, EBV may result in proliferation of B cells and post-transplant lymphoproliferative disease (typically in patients receiving allogeneic HSCT).
  • Acute leukaemia is a type of cancer that can develop a few years after HSCT.
  • Myelodysplasia or myelodysplastic syndrome is a bone marrow disorder that may develop a few years after HSCT in which the bone marrow makes defective blood cells.
  • Solid tumours that develop many years later may include the skin, mouth, brain, liver, cervix, thyroid, breast or bone.

Risk factors for developing a secondary cancer include:

  • total lymphoid irradiation (though it is seldom used as part of HSCT regimens for MS)
  • the type of high-dose chemotherapy used in the conditioning treatment
  • age (older than 40 years at the time of transplant)
  • infection with certain viruses, i.e. EBV, CMV, hepatitis B or hepatitis C.

Pharmacovigilance monitoring requirements and derisking strategies

Baseline

Full blood count, urea and electrolytes, liver function tests, thyroid function tests, serum protein electrophoresis, serum immunoglobulin levels, serology (varicella zoster virus [VZV], human immunodeficiency virus-1 and -2, hepatitis B and C, syphilis, EBV and CMV), tuberculosis enzyme-linked immune absorbent spot (TB ELISpot), up-to-date cervical smear and/or human papillomavirus testing and a pregnancy test. If indicated, some centres may assess the baseline function of the heart (ECG and cardiac ejection fraction) and lungs (lung function tests).

Follow-up

  • During HSCT, blood tests are frequently done to monitor for bone marrow recovery. If indicated, most units monitor peripheral blood EBV and CMV viral loads for EBV and CMV reactivation.
  • Once bone marrow function has recovered, blood tests are typically done 3 monthly for the first 2 years.
  • Endocrine work-up for women with persistent amenorrhea.

Infection prophylaxis

  • If you are VZV seronegative, you should receive the VZV vaccine at least 6 weeks before treatment with HSCT to allow sufficient time to develop immunity and protective antibodies.
  • To reduce your risk of developing listeriosis, which is a rare infection transmitted via food, you should receive advice about starting a listeriosis diet and a behavioural programme to minimise your chances of exposure to the infectious agent.

Depending on where you have your HSCT, you may also be offered antibiotic prophylaxis to reduce your chances of developing bacterial, fungal and parasitic infections.

Rebaselining

A rebaseline MRI needs to be done after HSCT. Most units do this after bone marrow recovery once patients have had time to recover from the HSCT procedure – typically at around 6 months.

Pregnancy

Pregnancy is contraindicated during HSCT as some chemotherapies are teratogenic and may harm the developing foetus. While having HSCT, women who might become pregnant should use effective birth control.

Breastfeeding

Some chemotherapy agents are excreted in human milk; therefore, breastfeeding should be discontinued before starting HSCT.

Vaccination

Immunisation is likely to be ineffective when given during or after HSCT. Immunisation with live virus vaccines is generally not recommended until after the immune system has reconstituted. Some units recommend a routine revaccination programme approximately 2 years after HSCT. The need for revaccination depends on the intensity of the chemotherapy regimen used during conditioning; the more intensive the regimen, the more likely you are to be revaccinated.

Switching-2-HSCT

HSCT repeat course

HSCT is not a typical IRT in that it is usually given as a single one-off treatment. Therefore, breakthrough MS disease activity after HSCT usually triggers the introduction of another licensed DMT. However, there are case reports of patients with MS and other autoimmune diseases having repeat HSCT.

DMTs

HSCT is indicated as part of routine clinical care in the occasional patient with malignant MS who has already failed licensed treatment options. In such patients, the benefits of HSCT outweigh the risks of the disease. Provided the baseline screening tests are acceptable and there are no specific contraindications in an individual patient, I see no reason why HSCT can’t be used after any licensed DMTs. However, there are some specific caveats highlighted below.

Interferon-beta and glatiramer acetate

HSCT is indicated as part of routine clinical care in the occasional patient with malignant MS who has already failed licensed treatment options. In such patients, the benefits of HSCT outweigh the risks of the disease. No contraindications or specific issues.

Alemtuzumab and mitoxantrone (non-selective cell depleting DMTs)

A persistently low peripheral white cell count post-alemtuzumab or post-mitoxantrone, i.e. a neutrophil count <1000/mm³ or a total lymphocyte count <800/mm³, is a relative contraindication to HSCT. Another hit on the bone marrow and the primary and secondary lymphoid organs may worsen your leukopaenia and render you more immunosuppressed. The decision to use HSCT in this situation must be based on the potential benefits of HSCT versus its risks and the risks of untreated active MS. 

Cladribine (selective cell-depleting DMT)

A persistently low peripheral lymphocyte cell count post-cladribine, i.e. a total lymphocyte count <800/mm³, is a relative contraindication to HSCT. The effect of HSCT on primary and secondary lymphoid organs may worsen lymphopaenia. However, the decision to use HSCT after cladribine must be based on the potential benefits of HSCT versus the risks of lymphopaenia and the risks of untreated active MS. 

Anti-CD20 therapies (selective cell depleting DMTs)

As ocrelizumab, ofatumumab, rituximab and ublituximab are selective B cell-depleting agents, it is theoretically much safer to use HSCT after one of these DMTs than after the other less selective and non-selective agents. An anti-CD20 is the safest cell depleting DMT to use before HSCT.

S1P modulators (fingolimod, siponimod, ozanimod and ponesimod)

Chemotherapy is used before HSCT to ‘mobilise’ the stem cells (that is, cause them to move from the bone marrow into the blood). Therefore, an adequate wash-out period is needed after stopping an S1P modulator before starting the HSCT procedure to allow recovery of peripheral lymphocyte counts. To prevent persistent lymphopaenia post-HSCT, the peripheral lymphocyte counts must return towards normal (>800/mm³) or be normal (>1,000/mm³) before starting HSCT.  

Natalizumab

As HSCT is a non-selective IRT that can’t be rapidly reversed, it is critical to ensure against asymptomatic PML. Carry-over PML from natalizumab to HSCT would potentially be fatal. A baseline MRI scan and possibly a CSF examination must therefore be done before starting HSCT, to exclude possible PML.

Fumarates

Fumarates reduce the lymphocyte count by approximately 30% in people with MS, or by even more in some individuals. Therefore, patients with lymphopaenia while taking a fumarate may be more susceptible to developing clinically significant prolonged lymphopaenia post-HSCT. 

Teriflunomide

Because teriflunomide is an antiproliferative agent, it may delay or prevent the recovery of the peripheral white cell count post-HSCT. One option is to do an accelerated teriflunomide washout to prevent this potential problem. Interestingly, rheumatologists who use leflunomide, a prodrug converted to teriflunomide, don’t use an accelerated washout when using antiproliferative agents post-leflunomide.

Special circumstances

Specific comorbidities and adverse events may make it difficult to start HSCT after certain DMTs, for example, the development of chemotherapy-related cardiomyopathy post- mitoxantrone. 

References

  1. RCT comparing autologous hematopoietic stem cell transplantation versus alemtuzumab, cladribine or ocrelizumab in MS (RAM-MS). ClinicalTrials.gov ID NCT03477500.
  2. Best available therapy versus autologous hematopoetic stem cell transplant for multiple sclerosis (BEAT-MS). ClinicalTrials.gov ID NCT04047628.
  3. StarMS HSCT trial opening at hospitals around the UK. MS Society, UK, October 2022.
Pregnancy and childbirth, Women's health

Planning for pregnancy

This article discusses the effects of MS on fertility, decisions about starting or stopping a DMT, the use and safety of oral contraceptives and the possible impact of in vitro fertilisation on MS disease course.

Does MS affect my fertility?

No, MS does not affect fertility. Women and men with MS are as fertile as people without MS. However, MS does not protect women and men from other causes of infertility. Fertility treatment may impact MS (see below). Please be aware that mitoxantrone, AHSCT (autologous haemopoietic stem cell treatment) and other chemotherapy treatments, such as cyclophosphamide used off-label to treat MS, may be toxic to ovarian and testicular function and require egg and sperm banking before treatment.

Should I go onto a DMT and get my MS under control before starting a family or first start my family?

In general, I recommend that women with active MS delay pregnancy until their disease is under control, optimise their general health and prepare properly for becoming a parent. There is no point in having active MS, not starting a DMT and having a catastrophic relapse in the period during which you are trying to fall pregnant.

However, a desire to start or extend your family should not change the way you want your MS managed. Early effective treatment, treating to a target of NEIDA, potentially flipping the pyramid, preventing end-organ damage and the holistic management of MS are all compatible with pregnancy. There are no rules for implementing this strategy in pregnancy because all decisions should be personalised. For example, a woman with rapidly evolving severe MS may choose natalizumab and stay on it throughout pregnancy and while breastfeeding because her MS was so active and potentially devastating. Another woman who is young, risk adverse and with a very good prognosis may choose to delay starting a DMT until she has had a child. Yet another woman, diagnosed at 40, may not want to delay falling pregnant and may opt for a DMT that is safe during pregnancy.

It is up to the person with MS, their partner and sometimes their extended family to make the final decisions about how to manage their MS during pregnancy. The healthcare professional (HCP) is there to provide information and guidance in this process.

Are oral contraceptives safe in people with MS?

To my knowledge, contraceptives are safe and effective in women with MS. The same contraindications and relative contraindications to specific contraceptives apply to women with MS as to the general population. Hormonal contraceptives are associated with an increased risk of thrombosis; women with MS who are immobile thus have a higher risk of deep vein thrombosis than those who are mobile.

Which contraceptive would you recommend?

MS should not be the deciding factor around the choice of contraceptive unless the degree of MS-related disability makes managing menstrual hygiene difficult. In this case, contraceptives that suppress menstruation have advantages, for example, continuous hormonal contraceptives or the progestin-tipped intrauterine contraceptive device (Mirena).

Inclusion criteria for participation in specific drug trials sometimes mandate double contraception, for example, a hormonal contraceptive and a barrier method. This is to try and avoid accidental pregnancies while taking an investigational compound without a safety track record in humans.

How long before I fall pregnant must I stop my DMT?

It depends on which DMT you are taking. Only the DMTs that are teratogenic or potentially teratogenic (i.e., may cause foetal malformations) need to be stopped before you fall pregnant. It is essential to allow sufficient time for these agents to be eliminated from the body.

Teriflunomide

Teriflunomide has the potential to cause birth defects; therefore, patients must have effective contraception whilst on this treatment. It has a very long half-life because it is reabsorbed in the intestine and is eliminated slowly from the plasma. Without an accelerated elimination procedure, it takes up to 8 months to reach plasma concentrations of less than 0.02 mg/l, which are considered safe. Remarkably, due to individual variations in teriflunomide clearance, it may take up to 2 years to fall to acceptable levels. An accelerated elimination procedure with cholestyramine or activated charcoal can be used at any time after the discontinuation of teriflunomide.

Teriflunomide accelerated elimination procedure

After stopping treatment with teriflunomide:

• Cholestyramine 8 g is administered three times daily for 11 days, or cholestyramine 4 g three times a day can be used if cholestyramine 8 g three times a day is not well tolerated.

• Alternatively, 50 g of activated powdered charcoal is administered every 12 hours for 11 days.

Following either of the accelerated elimination procedures, it is recommended to verify elimination by checking teriflunomide blood levels and allow a waiting period of 1.5 months between the first occurrence of a plasma concentration below 0.02 mg/l and planned fertilisation.

S1P modulators

S1P modulators are contraindicated during pregnancy, owing to the risk to the foetus. Before starting treatment in women of childbearing potential, we do a urine pregnancy test. Women taking an S1P modulator must use effective contraception during treatment and then continue for:

  • 2 months after stopping treatment with fingolimod (Gilenya)
  • 10 days after stopping treatment with siponimod (Mayzent)
  • 3 months after stopping treatment with ozanimod (Zeposia)
  • 7 days after stopping treatment with ponesimod (Ponvory).

Stopping the S1P modulators brings the potential for rebound disease activity, so most neurologists now prefer to transition women on one of these therapies to another class of DMT that is considered safer in pregnancy.

Safer options

Safer options during pregnancy include an injectable (interferon-beta or glatiramer acetate), a fumarate, an anti-CD20 therapy, natalizumab or an immune reconstitution therapy (cladribine or alemtuzumab). I cover some of the issues related to anti-CD20 therapies in the MS-Selfie case study ‘Wait to fall pregnant or start a DMT now?’.

The good news is that several DMT options are now available to women with MS wanting to fall pregnant.

Can I have IVF, and what will IVF do to my MS?

There is no reason why a person with MS cannot have IVF (in vitro fertilisation). However, there appears to be a slightly increased risk of relapse after IVF and egg harvesting. Whether this is due to stopping DMTs before undergoing IVF or due to the drugs used to stimulate ovulation is unknown. Studies reporting an increase in disease activity after IVF are more likely to be published than studies not showing such an increase so that publication bias may affect the findings. I recommend viewing IVF as a planned pregnancy and giving women with MS the option of receiving a DMT that is relatively safe in pregnancy or treating their MS with immune reconstitution therapy before IVF.

References

Krysko KM et al. Treatment of women with multiple sclerosis planning pregnancy. Curr Treat Options Neurol 2021;23:11.

Other articles in this series on Pregnancy and childbirth:
Managing MS during pregnancy
Preparing to give birth
Breastfeeding if you are on a DMT
Concerns about parenting

DMTsSafety, Monitoring MS

How can I reduce my chances of adverse events on specific DMTs?

The complications associated with immunosuppression vary from DMT to DMT. You will find it helpful to understand what investigations to expect before and during treatment and how these may vary depending on the DMT(s) you are considering.

Key points

  • Numerous tests are carried out at the start of your treatment (baseline); these include blood, urine and tests for a range of infections.
  • Some patients will need tests or procedures specific to their DMT that are inappropriate for everyone with MS – for example, vaccination against some infections; pregnancy and/or genetic counselling; prevention of cardiovascular complications; and management of infusion reactions.
  • Ongoing monitoring is required for many but not all of the above factors.
  • All licensed MS DMTs have had a thorough risk ̶ benefit assessment, and their benefits are considered to outweigh the potential risks.

Standard tests … and why we do them

If you have read the article on immunosuppression, you will know that immunosuppressive DMTs may reduce white blood cell counts and antibody responses to vaccines and increase the likelihood of some infections and cancers. However, we can reduce the risk of many complications associated with long-term immunosuppression (we use the shorthand ‘de-risk’). This article explains what needs to be done at the start of DMT administration (baseline) and during subsequent monitoring. The specifics, however, vary from DMT to DMT.

Baseline tests

Tests at baseline (before starting DMT administration) include full blood count, platelets, liver, kidney and thyroid function tests, and a urine screen. Recording baseline immunoglobulin levels is particularly important if you are about to start an anti-CD20 therapy (ocrelizumab, ofatumumab or rituximab) so that we have a reference level for future comparisons. 

Serum protein electrophoresis is done for patients considering starting interferon-beta; having a so-called monoclonal gammopathy (an abnormal immunoglobulin) is a contraindication to starting an interferon-beta formulation in people with MS. The drug has been associated with a form of capillary leak syndrome, leading in rare cases to death from an adult respiratory distress syndrome.

The table below summarises the routine investigations required at baseline; subsequent sections provide further detail.

Tests routinely carried out at the start of treatment (baseline).
AHSCT, autologous haematopoietic stem cell transplantation; CMV, cytomegalovirus; CSF, cerebrospinal fluid; DMT, disease-modifying therapy; EBV, Epstein ̶ Barr virus; ECG, electrocardiogram; FBC, full blood count; HIV, human immunodeficiency virus; HPV, human papillomavirus; JCV, JC virus; LFTs, liver function tests; MMR, measles/mumps/rubella; MRI, magnetic resonance imaging; PCP, pneumocystis pneumonia; PML, progressive multifocal leukoencephalopathy; TB ELISpot, tuberculosis enzyme-linked immune absorbent spot; TFTs, thyroid function tests; U&E, urea and electrolytes; VZV, varicella zoster virus.

Infection screening

At our centre, we screen for a relatively large number of infectious diseases so that we can treat any subclinical infection before starting a DMT. This is particularly relevant for HIV-1 and 2, hepatitis B and C, syphilis and tuberculosis (TB).  

Screening for the JC virus (JCV), which causes progressive multifocal leukoencephalopathy (PML), is only really needed for people with MS considering starting natalizumab. Even if you are JCV positive, you can be treated with natalizumab for 6 ̶ 12 months and sometimes longer if you are prepared to take on the risk of PML and the extra monitoring required to detect PML early. 

We only check measles/mumps/rubella (MMR) status in patients without documentation of full vaccination as children. We check varicella zoster virus (VZV) status before starting immunosuppression and vaccinate seronegative individuals. Currently, we are still using the live VZV vaccine. This will change, and we will likely be offering all people with MS in the UK the component inactive VZV vaccine (Shingrix, that has had its licence extended) to reduce the chances of zoster reactivation in all adults starting immunosuppression. This new Shingrix indication is similar to the pneumococcal vaccine (Pneumovax). Our centre is only recommending Pneumovax in patients about to start an anti-CD20. However, when Shingrix becomes available on the NHS, it will make sense to bundle this with the Pneumovax and make it routine for all people with MS before starting immunosuppressive therapy. Please check with your healthcare team which products are available locally.

Routine tests and monitoring for Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are only needed for subjects undergoing autologous haematopoietic stem cell transplantation (AHSCT), which causes profound short-term immunosuppression that can result in CMV and EBV reactivation. CMV reactivation also occurs with alemtuzumab, so this needs to be considered when investigating patients who develop complications after receiving alemtuzumab (please see Opportunistic infection in MS). 

For patients starting long-term immunosuppression, it is advisable to screen for active human papillomavirus (HPV) infection (by cervical smear or vaginal swab) and for warts or active infection with molluscum contagiosum. Warts are caused by HPV skin infection; molluscum contagiosum is due to a relatively benign pox virus that typically affects young children but occasionally affects adults. Warts and molluscum contagiosum can spread rapidly in patients receiving alemtuzumab, so I recommend treating these skin infections before starting immunosuppression for MS. 

Vaccinations

We encourage all patients to be vaccinated against COVID-19 and seasonal flu; outside the flu vaccine season, we remind people to get vaccinated during the next vaccine season. 

Hepatitis B, meningococcal and Haemophilus influenzae vaccines are considered only for people with MS who are at high risk of infection and have not had these vaccines as part of a national vaccine programme, i.e. healthcare and laboratory workers for hepatitis B, school and university students and military recruits for meningococcal vaccine and paediatric patients for Haemophilus influenzae. 

The issue around having the HPV vaccine as an adult is more complex. For example, in the UK, the NHS does not cover the cost of the vaccine for people over 25. In addition, most people have only had the quadrivalent vaccine (Gardasil-4), which covers about two-thirds of the strains that cause cancer. Some people with MS may want to upgrade their immunity with the polyvalent vaccine (Gardasil-9) that covers over 95% of the cancer-causing strains of HPV. For more information on HPV vaccination, please see Case study: cervical intraepithelial neoplasia (CIN) and ocrelizumab.

MMR is a live vaccine given in childhood (see MMR vaccine: to vaccinate or not? ). Owing to vaccine hesitancy, however, many people do not receive this vaccine as children. Therefore, if an adult with MS is about to start immunosuppressive therapy and has not been vaccinated against MMR, we advise them to do so. This is particularly important for people about to start natalizumab because these viruses are neurotropic and can infect the brain. Natalizumab blocks immune response within the brain; hence, exposure to a neurotropic virus could cause serious infection, similar to what we see with the JC virus – which causes PML.

Travel vaccines for people who travel as part of their work or plan to travel shortly need to be considered. In particular, the yellow fever vaccine is a live vaccine (made from a weakened yellow fever virus strain) and it should ideally be given before someone starts on immunosuppressive therapy. 

Cardiovascular screening

You may need an ECG (electrocardiogram), to rule out an abnormal heart rhythm or electrical conduction abnormality and to check your left ventricular function (ejection fraction). These abnormalities are a relative contraindication to using the S1P modulators (fingolimod, siponimod, ozanimod, ponesimod), which may affect the conduction of the heart. In patients treated with mitoxantrone, the left ventricular ejection fraction (LVEF) must be done at baseline and regularly monitored because mitoxantrone is toxic to the heart. If the LVEF drops significantly, further dosing of mitoxantrone is contraindicated. 

Pregnancy, family planning and genetic testing

Many chemotherapy agents used in AHSCT for ablating (extracting) the bone marrow are toxic to the ovaries and testes. Therefore, patients receive counselling before treatment and can have eggs (oocytes) or sperm banked for future use. Egg banking is also a consideration for women with MS being treated with mitoxantrone. Men receiving mitoxantrone do not need to bank sperm, however, because mitoxantrone does not cross the testes ̶ blood barrier. 

Genetic testing is only required at present if you wish to receive siponimod. Siponimod is metabolised by a specific liver enzyme (biological catalyst) with two functional variants – slow metabolising and fast metabolising. People who carry two slow-metabolising variants of the enzyme cannot receive siponimod. Intermediate metabolisers (those that carry one slow- and one fast-metabolising version of the enzyme) receive low-dose siponimod, while those with two fast-metabolising enzymes receive high-dose siponimod. 

Protecting against progressive multifocal leukoencephalopathy

I have included magnetic resonance imaging (MRI) and lumbar puncture with cerebrospinal fluid (CSF) testing for JCV among the baseline tests. This is specific to patients at high risk of developing PML who are switching from natalizumab to a depleting immune reconstitution therapy such as alemtuzumab or another therapy that depletes their immune system (e.g. cladribine or an anti-CD20 therapy). These tests are done to exclude asymptomatic PML, which will otherwise be carried over to the new treatment. The effects of these immunosuppressive therapies on your immune system cannot be rapidly reversed, which is a problem because immune reconstitution is needed to clear PML. Most MS centres do not mandate CSF testing in this situation because it does not always reveal the presence of PML. However, I still request this test on my patients to gain as much information as possible on which to base potentially life-changing decisions.

Prophylactic antivirals and antibiotics

Patients in our centre undergoing AHSCT or receiving alemtuzumab will be given antivirals and antibiotics to reduce the likelihood of certain infections. This is particularly relevant for listeriosis, which is a rare infection transmitted via food. We also encourage all our patients to start and maintain a specific diet to reduce the chances of listeriosis. The risk of listeriosis is only present for a short period when both the adaptive and innate immune systems are compromised, that is, for 4 weeks after receiving alemtuzumab, so we recommend antibiotic prophylaxis for 4 weeks. Our online resource provides more information about listeriosis. If you live in the UK, you can order our free listeriosis prevention kit, which contains a booklet (also downloadable) and various practical items to help keep you safe.

Strategies for limiting the risks from immune reconstitution therapies and infusion DMTs.

Infusion reactions

When you use agents that cause cell lysis (breakdown), such as alemtuzumab and intravenous anti-CD20 therapies, the contents of cells cause infusion reactions. To prevent such reactions or reduce their severity, we pretreat patients with corticosteroids, antihistamines and antipyretics. The exact protocols for each DMT differ; for example, ocrelizumab infusion reactions are generally only a problem with the first and second doses; therefore, many centres don’t give steroids with the third and subsequent infusions. The latter was particularly important during the COVID-19 pandemic when it was shown that the recent administration of high-dose steroids increased your chances of severe COVID-19. 

Ongoing monitoring

Once someone has been treated with a DMT, ongoing monitoring is required. What gets monitored and how frequently depends on the individual DMT. For a list of DMTs associated with important adverse events, please see our summary Table in ‘De-risking’ guide: monitoring requirements of individual DMTs.

The regulatory authorities usually put in place specific monitoring requirements, which can differ worldwide. It is important that you also enrol in your national cancer screening programmes. Being on chronic immunosuppression increases your chances of developing secondary malignancies, so please remain vigilant. 

Tests carried out regularly as part of ongoing monitoring.
FBC, full blood count; LFTs, liver function tests; MRI, magnetic resonance imaging; PML, progressive multifocal leukoencephalopathy; TFTs, thyroid function tests; U&E, urea and electrolytes.

I want to reassure you that all licensed MS DMTs have undergone a thorough risk ̶ benefit assessment by the drug regulators, and the benefits of these treatments are considered to outweigh the potential risks. On balance, the level of immunosuppression associated with MS DMTs is typically mild to moderate; hence, the complications are relatively uncommon. MS is a serious disease and, if left to run its natural course, would result in most patients becoming disabled. To learn more about the natural course of MS, please read the section entitled What are the consequences of not treating MS?

DMTsSafety, Monitoring MS

‘De-risking’ guide: monitoring requirements of individual DMTs

Before you start taking a disease-modifying therapy (DMT), your MS team will carry out routine tests and investigations, many of which are repeated during subsequent monitoring or before switching to another DMT. The regulatory authorities that license the drugs specify their monitoring requirements. What gets monitored and how frequently depends on the individual DMT.

All licensed MS DMTs have undergone a thorough risk ̶ benefit assessment by the drug regulators, and the benefits of these treatments are considered to outweigh the potential risks. The table below summarises the main monitoring requirements of individual DMTs or DMT classes. For more detailed information, see the post on reducing your chances of adverse events.

AHSCT, autologous haematopoietic stem cell transplantation; CMV, cytomegalovirus; CSF, cerebrospinal fluid; EBV, Epstein ̶ Barr virus; ECG, electrocardiogram; HPV, human papillomavirus; JCV, JC virus; LVEF, left ventricular ejection fraction; MRI, magnetic resonance imaging; PML, progressive multifocal leukoencephalopathy.

DMTs, Treatment strategy

How immunosuppressed am I?

Do you understand the difference between short-term intermittent and long-term continuous immunosuppression? Here we address another of the key questions to consider before deciding on a specific disease-modifying therapy (DMT).

Key points

  • Immunosuppressive disease-modifying therapies (DMTs) reduce the immune system’s effectiveness.
  • It is important to weigh up the benefits and risks of short-term versus continuous immunosuppression.
  • Non-selective DMTs suppress the adaptive and innate immune systems; selective DMTs do not affect the innate immune system and are thus associated with a low risk of bacterial infections.
  • The implications of immunosuppression need to be considered within the context of other health and lifestyle factors.

Which DMTs cause immunosuppression?

A useful way of thinking about DMTs is based on whether they are immunosuppressive. Broadly speaking, an immunosuppressive is any DMT that reduces the immune system’s activation or effectiveness. 

From a regulatory perspective, for a drug to be classified as immunosuppressive, it should: 

  • cause significant lymphopaenia or leukopenia (reduced white cell counts)
  • be associated with opportunistic infections (infections that don’t occur in people with a normal, healthy immune system)
  • reduce antibody and/or T-cell responses to vaccines 
  • increase the risk of secondary malignancies. 

Based on the above criteria, the interferon-beta preparations and glatiramer acetate are immunomodulatory rather than immunosuppressive. Teriflunomide is also an immunomodulatory therapy with the potential, albeit small, to cause immunosuppression. In real life, however, very few people with MS treated with teriflunomide develop significant lymphopaenia or leukopenia; if they do, we tend to stop the drug. The other licensed DMTs are immunosuppressive to a greater or lesser degree. 

Short-term versus continuous immunosuppression

The duration and intensity of immunosuppression further determine the risks. Short-term or intermittent immunosuppression associated with an immune reconstitution therapy (IRT) front-loads the risks, which decrease substantially once the immune system has reconstituted itself. In comparison, long-term continuous or persistent immunosuppression, which occurs with most maintenance DMTs, accumulates problems over time, particularly opportunistic infections and secondary malignancies.

Live vaccines are, in general, contraindicated in patients on continuous immunosuppressive therapies. However, someone with MS on an IRT who has reconstituted their immune system can tolerate and respond to live vaccines. The benefits of administering live vaccines always need to be balanced against the risks of the vaccine.

How immunosuppressed are you table updated format 180625 SS

The main characteristics of continuous persistent and short-term (intermittent) immunosuppression. Modified from Giovannoni, Curr Opin Neurol.1
AHSCT, autologous haematopoietic stem cell transplantation; PML, progressive multifocal leukoencephalopathy.

Selective versus non-selective immunosuppression

Immunosuppression that accompanies DMTs may be selective or non-selective. Non-selective therapies deplete and/or suppress both the adaptive immune system (T cells and B cells) and the innate immune system (monocytes, neutrophils and natural killer [NK] cells). Alemtuzumab, AHSCT (autologous haematopoietic stem cell transplantation) and mitoxantrone are non-selective and are therefore associated with acute bacterial infections such as listeriosis, nocardiosis and cytomegalovirus reactivation. In comparison, anti-CD20 agents (ocrelizumab and ofatumumab) and cladribine are selective, do not affect the innate immune system and are therefore associated with a low risk of acute bacterial infections. 

How immunosuppressed are you_MET vs IRT_2 Dec 2024

Classification of disease-modifying therapies for relapsing forms of MS. Modified from Giovannoni, Curr Opin Neurol.1
AHSCT, autologous haematopoietic stem cell transplantation.

Other considerations

Please note that the implications of immunosuppression are not black and white but interact with other factors such as:

These factors have been highlighted during the COVID-19 pandemic, particularly in relation to the risk of severe COVID-19 and the variations in vaccine responses among people with MS (including waning of the immune response).

It is important to realise that we can derisk (reduce the risk of) some complications associated with long-term immunosuppression and the use of DMTs. Please see the post entitled How can I reduce my chances of adverse events on specific DMTs?

References

  1. Giovannoni G. Disease-modifying treatments for early and advanced multiple sclerosis: a new treatment paradigm. Curr Opin Neurol 2018;31:233 ̶ 43.
DMTs, Treatment strategy

How do I want my MS to be treated?

What is the difference between a maintenance ̶ escalation DMT and an immune reconstitution therapy (IRT)? Why is it important to understand the distinction?

Key points

  • Maintenance–escalation and immune reconstitution therapy (IRT) are two approaches to MS treatment currently favoured.
  • IRT is a one-off, short course which acts on immune system cells in three stages: reduction, repopulation and reconstitution.
  • Maintenance–escalation is given continuously without interruption. If it does not work well, the treatment is changed to a more effective DMT (known as ‘escalation’).
  • Additional future approaches are likely to include induction ̶ maintenance and/or combination therapy.

If I had MS, how would I want to be treated? This is a difficult question, and one that many of my patients ask me. The answer depends on your life stage, what risks you are prepared to take, personal factors such as family planning considerations and the extent of your understanding of MS and how we approach its treatment.

Currently, there are two main philosophies regarding the treatment of MS with DMTs: maintenance/escalation versus immune reconstitution therapies (IRTs). 

What is an immune reconstitution therapy?

By definition, an IRT is given as a short course, i.e. as a one-off treatment in the case of autologous haematopoietic stem cell transplantation (AHSCT) or intermittently in the case of alemtuzumab, cladribine or mitoxantrone. IRTs are not given continuously, and additional courses of the therapy are given only if there is a recurrence of MS inflammatory activity. IRTs can induce long-term remission and, arguably, in some cases a potential cure.

IRTs have three phases to their mode of action, which I refer to as the ‘three Rs’.

  1. Reduction, or depletion, when we try to kill the autoimmune cells that cause MS.
  2. Repopulation, when the immune system recovers from stem cell transplantation and, hopefully, the autoimmune cells don’t return.
  3. Reconstitution, when the immune system is recovered and fully competent. The recovered immune system following treatment with an IRT is different from what was there before. Some people like to think of an IRT as a reboot of the immune system, but without MS.
Slide1

The three Rs of immune reconstitution therapy: reduction, repopulation and reconstitution. From Giovannoni, Curr Opin Neurol.1 

What is an MS ’cure’?

One attempt at a definition describes an MS cure as no evidence of disease activity (NEDA) 15 years after the administration of an IRT. I justify using 15 years because it is the time-point most accepted for defining ‘benign MS‘ and is also beyond the average time to onset of secondary progressive MS in natural history studies.

What is a maintenance therapy?

A maintenance therapy is given continuously without an interruption in dosing. Although maintenance therapies can induce long-term remission (i.e. NEDA), they cannot result in a cure. The recurrence or continuation of inflammatory disease activity with maintenance therapies is an indication of a suboptimal response to treatment and typically results in a treatment switch. Ideally, this switch should be to a more effective class of DMTs – hence the term ‘escalation’. 

What would I recommend?

I can’t choose for you. The debate is complex and depends on many factors. One important consideration is vaccine readiness: will I be able to mount an adequate immune response to a vaccine? IRTs have the advantage that they allow reconstitution of the immune system; once it recovers, vaccine responses are restored, and even live vaccines can be given.

The table below highlights key differentiators. Further, detailed information about most of the products listed in the Table can be accessed through the DMT comparison tool available at ClinicSpeak or via the Multiple Sclerosis Trust MS Decisions aid.

Similarities and differences between maintenance treatments and immune reconstitution therapies. Registered trade names (UK market) of the generic drugs listed are shown in brackets. *How to define a ‘cure’ in MS is controversial. Modified from Giovannoni, Curr Opin Neurol.1
DMT, disease-modifying therapy; HSCT, haematopoietic stem cell transplant; IRT, immune reconstitution therapy.

The future

I envisage two more treatment strategies emerging.

  • One approach is induction ̶ maintenance therapy, using an IRT followed by an immunomodulatory therapy rather than an immunosuppressive DMT (which is a safer option) the aim is to keep MS in long-term remission. This approach is used in oncology, where the cancer is hit hard with induction chemotherapy and then kept at bay with a well-tolerated maintenance therapy (e.g. antihormonal therapies in breast cancer).
  • Another approach is combination maintenance therapy; the aim would be to combine an anti-inflammatory therapy with, say, neuroprotective therapies to target smouldering MS.

The diagram below illustrates the scheduling of the four approaches discussed in this section. You may like to try out the DMT comparison tool to find out how some of the drugs listed in the comparison Table above align with your personal life choices and priorities.

Slide5

Four approaches discussed in this section. The white panels illustrate the two approaches currently available; the shaded panels illustrate two strategies that may emerge in the future. Modified from Giovannoni, Curr Opin Neurol.1

References

  1. Giovannoni G. Disease-modifying treatments for early and advanced multiple sclerosis: a new treatment paradigm. Curr Opin Neurol 2018;31:233 ̶ 43.