Deena Bearsley

(Reuters) – A Biogen Inc (NASDAQ) trial for an experimental treatment of an inherited amytrophic lateral sclerosis, (ALS), failed to achieve its primary goal. However, secondary measures and biomarkers revealed favorable trends, according to the company on Sunday.

Toby Ferguson from Biogen’s neuromuscular unit, said that Biogen would engage regulators and others “to understand how this data is meaningful and possible paths forward.” Biogen is currently treating patients from the trial in a follow up study. It recently opened a Phase 3 trial for tofersen in patients not suffering from ALS.

Tofersen is administered monthly directly to the spinal canal. It suppresses the production of SOD1, a protein which can build up to toxic levels in ALS sufferers with specific mutations. The genetic mutation is believed to cause around 2% of ALS cases.

Following 28 weeks, the 108 patient trial revealed a 1.2-point improvement in functional status of patients with fast progressing ALS. The difference was not statistically significant. The difference in patients with slower-progressing ALS was 1.4 points.

Guggenheim Partners recently reported that clinically, a decrease of at most 2 points is acceptable.

Biogen provided details from secondary trial results, which included breathing capacity and muscle strength. Patients treated with tofersen did better than patients receiving placebo, and patients who switched to tofersen in the extension phase experienced comparable gains.

According to Dr. Timothy Miller (the study’s principal investigator, and ALS Center Director at Washington University School of Medicine in St. Louis), “Despite there being no statistically significant differences in the primary endpoint,” there is a clinical sign here. At the American Neurological Association annual meeting, he presented tofersen results.

Also, patients who were given tofersen experienced lower levels SOD1 protein and lower levels plasma neurofilament lighter chain (a possible marker for nerve cell loss).

Dr. Miller stated that this suggests there may be an impact on the clinical functioning of the individual.

The majority of side effects experienced by trial patients included headaches and back pain. However, two patients suffered from spinal cord inflammation and 5.6% of patients who were enrolled in the tofersen study dropped out.

Globally, around 168,000 people have ALS, a fatal neurological disorder also known as Lou Gehrig’s disease. About 10% of cases can be attributed to genetic mutations.

Biogen has licensed tofersen to Ionis Pharmaceuticals Inc (NASDAQ:) Inc. Now, the company plans to provide early access for all SOD1-associated ALS patients. If a country allows such programs, patients have free access to the medicine before commercial licensing.

Biogen shares fell by around a third following the controversial U.S. Food and Drug Administration approval for Aduhelm in June. The decision by the FDA to approve Aduhelm was not based on proof it reduces brain-wasting protein plaques, but rather evidence of its cognitive enhancement.