Bone Marrow Transplant Most Useful for Younger Patients, MS Society Experts Suggest

Joana Carvalho, PhD avatar

by Joana Carvalho, PhD |

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A bone marrow transplant may be particularly useful for those with relapsing forms of multiple sclerosis (MS) who, despite treatment with high-efficacy disease-modifying therapies (DMTs), continue to experience relapses or show signs of new lesions, experts say.

According to new recommendations from the National Multiple Sclerosis Society, those under 50 who were diagnosed with MS within the last 10 years are likely the best candidates for the procedure. Society MS experts also emphasized that the transplant should only be carried out at specialized centers by experts in the field.

The Society’s new recommendations for bone marrow transplant in MS patients were recently published in a special communication, titled “Autologous Hematopoietic Stem Cell Transplant in Multiple Sclerosis Recommendations of the National Multiple Sclerosis Society,” in the journal JAMA Neurology.

An autologous hematopoietic stem cell transplant (AHSCT) is a type of bone marrow transplant in which healthy blood cell progenitors, known as hematopoietic stem cells, are collected from patients before they undergo a procedure called immunoablation to have their immune system partially or fully destroyed. In effect, immunoablation is a first step in resetting the body’s immune system. This procedure is usually done by treating patients with a variety of chemotherapy agents.

Once immunoablation is complete, the blood cell precursors collected earlier are re-infused back into the patient’s body to reconstitute and re-activate their immune system.

The end goal of this procedure is to fully “reboot” the patients’ immune system, so that they are left with less reactive immune cells that no longer attack and destroy the nerves’ protective myelin sheath.

Although AHSCT has been gaining popularity over the years, the way the procedure has been performed has varied from study to study. That makes it difficult for clinicians and researchers to assess and compare patient clinical outcomes.

These differences include not only the clinical features of those undergoing the procedure, but also a series of methodological aspects of the transplant itself, such as the agents used during immunoablation and the way blood cell progenitors have been stored and then given to patients.

In an attempt to help standardize the procedure, members of the Society’s National Medical Advisory Committee reviewed data from published studies to create a series of consensus recommendations on how and in whom AHSCT should be performed.

While reviewing the evidence, the experts noticed that AHSCT tended to be more effective and to be associated with greater durable long-term effects when performed in people with relapsing forms of MS. In contrast, based on available evidence, the experts suggested that individuals with progressive forms of the disease who showed no signs of recent MS activity were unlikely to benefit from the procedure.

“In addition, patients who are older and have greater disability have greater risk for serious complications or death associated with the procedure,” the experts wrote.

Based on these observations, the experts propose that the best candidates for AHSCT would likely be younger patients — those under age 50 — with relapsing forms of MS, who have had the disease for a decade or less, and who continued having relapses or new MS lesions despite treatment with highly effective DMTs. Those individuals for whom a treatment course with high-efficacy DMTs is unadvised also should be included in the “best candidates” group, the advisory committee members said.

Regarding treatment location, the experts recommend that, apart from clinical trials like the Phase 3 BEAT-MS study (NCT04047628) — which is currently recruiting participants in the U.S. — individuals considering undergoing AHSCT should do so at specialized centers. The patients’ healthcare team should be medical professionals who have experience with both AHSCT and MS.

The advisory committee members also noted that patients should seek out specialists certified by the Foundation for the Accreditation of Cellular Therapies, for those living in the U.S., or by the European Society for Blood and Marrow Transplantation, in the case of those living in European countries.

As for the protocol that should be adopted for AHSCT, the experts emphasized that additional research is needed to establish the optimal chemotherapy regimen for immunoablation, as well as the best conditions to harvest, store, and reintroduce hematopoietic stem cells back into patients.

“Larger randomized clinical trials [like BEAT-MS] are [also] needed to address the question of whether AHSCT has advantages over the most efficacious disease-modifying agents currently available,” the experts wrote.

It’s also recommended that clinical data from those undergoing the procedure be stored in a single registry database to make it easier to track patients’ outcomes and assess the treatment’s long-term safety and efficacy.

Treatment cost is likely another important factor for patients to consider when deciding between having a bone marrow transplant or continuing treatment with DMTs, the experts added.

“The estimated cost for AHSCT today is approximately $150,000, whereas treatment with DMTs currently entails a mean annual wholesale price of $80,000 or more, continuing indefinitely,” they wrote.

Regarding the current COVID-19 pandemic, the MS International Federation (MSIF) recently posted an advisory on its website for patients who underwent AHSCT during the pandemic, and whose immune system was severely weakened following immunoablation. Patients in these circumstances should consider prolonging the period they remain in isolation to a minimum of six months, the MSIF said.

Additionally, the MSIF noted that, in the case of those who are currently undergoing AHSCT and receiving intensive chemotherapy, treatment should be given in rooms separate from other hospitalized patients.