Plasma Exchange May Be Safe, Effective as Short-term MG Therapy

A new type of plasma exchange treatment, called double-filtration plasmapheresis (DFPP), may be effective and safe for short-term relief of myasthenia gravis (MG) symptoms, a review study has found.

These findings may have important clinical implications, especially for patients with severe or critical MG, the researchers noted.

The review, “Efficacy and safety of double-filtration plasmapheresis treatment of myasthenia gravis,” was published in the journal Medicine.

Plasmapheresis, a type of treatment that involves exchanging the plasma — the liquid component of blood — with fresh plasma, can ease the symptoms of autoimmune diseases like MG by filtering out self-reactive antibodies from the bloodstream. Such self-reactive antibodies drive the immune system to attack the body’s own tissues.

However, these plasma exchange therapies have been found in some cases to cause a series of complications, including allergic reactions and transfusion-related infections.

To overcome these complications, new plasma exchange methods have been developed. One such method is DFPP, which uses a two-step purification strategy to eliminate disease-causing autoantibodies.

“The use of DFPP to treat MG has increased over the past few decades; however, the choice of DFPP use is empirical and lacks consensus among doctors,” researchers wrote.

To provide a basis for informed decision-making, researchers in China set out to assess the efficacy and safety of DFPP for MG in a systematic, objective manner.

Using a method of analysis called meta-analysis, which combines the results of multiple studies, they collected information from a total of 329 patients with clinically confirmed MG who had been treated with DFPP in nine different clinical trials.

Controls were either healthy volunteers who had been treated with DFPP, or MG patients who had been treated with other therapeutic options.

The main study measure was to determine the rate of clinical efficacy, or how well DFPP succeeded in easing MG symptoms.

Analyses revealed that patients treated with DFPP were more than four times more likely to experience symptom relief and enter clinical remission compared with controls.

Researchers also analyzed other outcome measures, including changes in the levels of self-reactive antibodies directed against two proteins — acetylcholine receptor and titin — involved in MG development. Acetylcholine receptor is a protein that plays a key role in nerve-muscle communication, whereas titin is a structural protein of muscle cells.

DFPP was found in the analyses to effectively clear both antibodies from plasma. Moreover, the quantitative MG score, a clinical scale commonly used to assess MG severity, was lower in patients treated with DFPP than in controls, suggesting that treatment effectively reduced symptom severity.

Three of the studies included in the meta-analysis also had data on the duration of hospital stay and time to symptom remission for 136 patients.

Data from these studies showed the hospital stay of patients treated with DFPP was shortened by a mean of almost six days compared with controls. In addition, patients treated with DFPP achieved symptom remission a mean of three and a half days earlier than did the controls.

Only one study reported on side effects. Among 15 MG patients, two experienced low blood pressure and one developed a hematoma, or a pooling of blood within tissues.

According to the researchers, this “meta-analysis and systematic review supply evidence that DFPP treatment can effectively eliminate autoantibodies and has a definite clinical effect on MG patients.”

While DFPP appeared to be effective and safe for treating MG, the findings were heterogenous, meaning that they differed widely across studies. Therefore, as noted by researchers, they should be interpreted with caution.

“Because our review was limited by the quantity and quality of the included studies, the above conclusions should be verified by additional high-quality studies,” the researchers wrote.