Using biologic therapies may lead to better outcomes in myasthenic crises
Treatments tied to greater muscle strength, fewer steroids than standard MG care
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- Using biologic therapies to treat crises in myasthenia gravis may lead to better outcomes than the use of standard care, a new study found.
- While little difference was seen in effectiveness, treatment with such therapies led to improved muscle strength and reduced steroid use after six months.
- Still, the researchers called for larger studies to "further define the long-term use of biologic therapies" in MG.
Biologic therapies were associated with less steroid use and greater muscle strength than treatment with standard care among people recovering from a myasthenic crisis, a potentially life-threatening complication of myasthenia gravis (MG), a new study from China suggests.
Data showed that six months after leaving the hospital, individuals with MG who were treated with biologic therapies had better scores on a muscle strength measure — and needed lower doses of corticosteroids — than those receiving other treatments, including plasma exchange and intravenous immunoglobulin (IVIG). Still, MG patients in both groups continued to experience residual symptoms, the team noted.
“These findings suggest that the potential benefit of biologic therapies after myasthenic crisis may lie primarily in reducing subsequent treatment burden rather than achieving superior patient-reported functional recovery,” the researchers wrote, noting that “no significant between-group difference was observed” in patient-reported scores on an assessment of symptom severity and impact on daily function.
Among the biologic therapies used by patients in the prospective study were drugs such as Vyvgart (efgartigimod alfa-fcab) and Soliris (eculizumab), both approved in the U.S., the European Union, and elsewhere for people with MG.
The study, “Targeted biologics in muscle strength restoration and corticosteroid sparing for patients post-myasthenic crisis,” was published in the journal BMC Neurology.
In MG, the immune system mistakenly produces self-reactive antibodies that target proteins involved in nerve-muscle communication, resulting in symptoms of muscle weakness and fatigue. Weakness in the muscles people need to breathe may lead to a myasthenic crisis, which typically requires hospitalization and may lead to intensive care and mechanical ventilation.
Standard treatments such as corticosteroids, plasma exchange — a procedure in which the liquid part of blood is replaced — and IVIG, an antibody therapy, can help control crises. Still, recovery may be prolonged, and patients may experience persistent muscle weakness.
Scant data on use of biologic therapies for MG crises
Targeted biological therapies, including Vyvgart, Soliris, and rituximab — which work through different mechanisms to suppress the immune attack underlying MG — may also help patients recover from a myasthenic crisis. However, evidence on their use remains limited, particularly data on their longer-term effects.
This study, conducted by researchers in Shanghai, aimed to determine whether treatment with biological therapies could improve clinical outcomes compared with standard of care following a myasthenic crisis. It followed 112 MG patients recovering from a crisis for six months after being discharged from the hospital.
Among the patients, half received biologic therapies while the other half were given standard care during hospitalization and/or after discharge. The two groups were similar in terms of age —about 53 at the time of discharge — and sex, with nearly 60% women. Disease duration in both groups was approximately four years.
There were also no significant differences in duration of ventilatory support or length of stay in the intensive care unit or hospital, the researchers noted.
However, the groups differed in the rescue treatments used to manage the acute phase of the MG crisis. The use of IVIG alone was more common in patients receiving standard of care than in those receiving biological therapies (70% vs. 30%). Conversely, the use of plasma exchange alone or together with IVIG was more common in patients receiving biological therapies.
Less steroid use noted as key outcome
Six months after discharge, those in the biologic therapy group had a significantly lower MG Foundation of America-quantitative MG (MGFA-QMG) score than those receiving standard care (4.5 vs. 6.3). Because lower MGFA-QMG scores indicate better muscle strength, the finding suggests greater improvement in muscle function, according to the researchers.
Participants receiving biologic therapies also required lower doses of corticosteroids (14.7 vs. 22.0 mg/day), had lower cumulative corticosteroid exposure over six months (158.1 vs. 209.2 mg/day per month), and were less likely to use other immunosuppressive treatments (47% vs. 68%), the data showed.
The researchers noted that lower corticosteroid exposure may be particularly important given that the risks associated with these medicines increase with cumulative and prolonged use.
Still, the groups had similar patient-reported disease burden, with no significant differences in scores on the MG Activities of Daily Living (MG-ADL) scale at six months. Data also indicated that about a fifth of patients in the two groups continued to have MG-ADL scores of four or higher after the six-month follow-up, “indicating that a meaningful proportion of patients continued to experience clinically relevant functional impairment after discharge.”
Targeted biologics were associated with better objective muscle strength and reduced corticosteroid and immunosuppressant use after [myasthenic crisis].
During the six-month follow-up, respiratory infections were the most common adverse event in both groups, affecting three patients receiving biologic therapies and five on standard care. Herpes zoster (shingles) occurred in one patient in the biologic group compared with five in the standard-of-care group. Other adverse events were uncommon and occurred mainly among participants receiving standard care, the team noted.
Overall, “targeted biologics were associated with better objective muscle strength and reduced corticosteroid and immunosuppressant use after [myasthenic crisis],” the researchers concluded.
However, the team cautioned that the findings should be interpreted in light of the study’s observational design, use of different biologic treatments, the small number of patients, and the short six-month follow-up.
“Larger prospective studies with longer follow-up, comprehensive safety assessment, and health economic evaluation are warranted to further define the long-term role of biologic therapies after myasthenic crisis,” the researchers wrote.
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