Brainstorm’s NurOwn fails Phase III trial, demonstrating the struggle to develop effective ALS treatment

On 17 November, Brainstorm Cell Therapeutics announced topline results for its anticipated amyotrophic lateral sclerosis (ALS) stem cell therapy, NurOwn, as its Phase III trial did not reach statistically significant efficacy endpoints. NurOwn is the second pipeline drug to fail a clinical trial for ALS this year, following the failure of Orion’s ODM-109 (levosimendan) in a Phase III trial in July. This demonstrates the historical struggle to develop disease-modifying treatments for this rare disease, which has an aggressive nature. The high failure rate in ALS clinical trials may be attributed to the disease’s unclear etiology and complex pathophysiology.

NurOwn now faces a setback that might affect its approval and launch plans in this market, which has high unmet needs. This news is a disappointment to ALS patients, who currently only have two approved treatment options with limited efficacy. Therefore, there is still a high unmet need for efficacious disease-modifying treatments.

With NurOwn, a patient’s bone marrow-derived mesenchymal stem cells (MSCs) are treated in the lab to produce neurotrophic factors (NTFs), which are then delivered via intrathecal injection into the ALS patient to stimulate neuron regeneration and nerve-muscle interaction. However, key opinion leaders (KOLs) interviewed by GlobalData were uncertain if this approach was ready to be used in ALS patients given the lack of efficacy data and its challenging route of administration. Moreover, some KOLs noted that NurOwn’s social media advertising campaigns targeting ALS patients may deliver false hope and misconceptions to the patients and their families. As such, GlobalData previously estimated that, if successful, NurOwn would only generate average global sales of $82m by 2029 despite its expected high cost.

In this double-blind, placebo-controlled, Phase III trial, patients who received NurOwn achieved higher treatment response rate and ALS functional rating score (ALSFRS-R) compared to those who received placebo, yet the results of NurOwn could not outperform those of placebo. The primary endpoint was achieving assumed treatment response rates of 35% for NurOwn and 15% for placebo. The primary endpoint was achieved in 34.7% of participants receiving NurOwn, compared to 27.7% of participants receiving placebo.

However, the company highlighted that this clinical trial included a more severely affected ALS population compared to other recent ALS trials, and that NurOwn demonstrated meaningful improvement in a pre-specified subgroup of patients with early and less advanced disease across the primary and key secondary endpoints. NurOwn was also found to be well tolerated in rapidly progressing ALS patients. As such, NurOwn’s future is still in doubt, as the company is planning further discussions with regulators to evaluate the drug’s approval potential based on the current positive data in early ALS patients and the heterogeneity of this disease given its very limited treatment options.

Despite these pipeline failures, promising announcements were still made in the ALS space this year, with positive results from Biogen’s Phase II study of its gene therapy BIIB067 (tofersen) and Amylyx’s Phase II/III study of AMX0035.