The FDA plans to hold an Advisory Committee (AdCom) meeting to discuss BrainStorm Cell Therapeutics’s NurOwn for amyotrophic lateral sclerosis (ALS), the company reported Monday.

The AdCom announcement marks another surprising twist in NurOwn’s complicated drug development journey. In 2019, NurOwn failed to meet the primary endpoint of a Phase III trial (NCT03280056), raising expert doubts over the treatment’s efficacy.

The FDA then rejected NurOwn’s approval application in November 2022 before Monday’s unexpected reversal.

In the meantime, patient advocates have pushed for NurOwn’s consideration given the high unmet need in ALS, and the agency appears to have taken note. Though the AdCom meeting does not mean NurOwn will receive FDA approval, it does mean patient advocates, company representatives, and outside experts will have a public forum to weigh in on the treatment. BrainStorm and the FDA have not yet announced the date of the planned meeting.

NurOwn uses patient’s bone marrow-derived mesenchymal stem cells, which are treated in the lab and delivered via intrathecal injection. The treatment is intended to provide neuroprotection, promote new motor neuron growth, and improve nerve-muscle interactions. BrainStorm is also using its stem cell platform to develop potential new biomarkers for ALS.

NurOwn AdCom follows recent ALS meetings

The news of NurOwn’s AdCom comes on the heels of a high-profile AdCom meeting in the ALS space just last week. On March 22, AdCom panelists overwhelmingly supported accelerated approval for Biogen’s tofersen in a rare form of ALS.

Though tofersen missed its primary efficacy endpoint in a Phase III study (NCT02623699), panelists agreed the drug’s effect on the surrogate marker of plasma neurofilament was “reasonably likely” to predict clinical benefit in ALS. The FDA will make its final approval decision by April 25.

Though the FDA generally follows the recommendation of its AdCom, it occasionally makes differing approval decisions. In one notable example, the FDA approved Amylyx’s Relyvrio (sodium phenylbutyrate and taurursodiol) for ALS in September 2022 despite a negative AdCom meeting earlier that year.

In a time of uncertainty for rare disease approvals, the newly announced AdCom could set the stage for another potential ALS approval this year. Meanwhile, the ALS drug development pipeline continues to progress as a slate of therapies look to capitalize on key trial readouts last year.

Correction: This article originally stated that the FDA rejected NurOwn’s approval application twice, referencing a March 2021 statement from the FDA in response to an ALS patient advocacy campaign for NurOwn. The article has been updated to reflect FDA’s official communication in the November 2022 refusal to file letter.