AB Science jumps 40% as optimism trumps skepticism in wake of PhIII ALS data

AB Science (EPA:AB) is claiming a big win in its long-running attempt to bring masitinib to market. A Phase II/III trial of the drug in people with amyotrophic lateral sclerosis (ALS) met its primary endpoint, sparking a 40% jump in AB Science's stock while simultaneously raising questions about whether this will prove to be another false dawn for the company.

The double-blind Phase II/III clinical trial gave participants Sanofi's ($SNY) ALS drug Rilutek plus either AB Science's tyrosine-kinase inhibitor masitinib or a placebo. In an interim analysis of the first 191 patients to undergo 48 weeks of treatment, masitinib was associated with superior performance on the revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R). The result, which by AB Science's predefined criteria amounted to a success, sent shares in the company up 40%, a rise that continued into the next day.

Paris-based AB Science now has its eye on regulatory approvals. "We plan to share the data with EMA and FDA to discuss the possibility of filing an application for marketing authorization for masitinib in ALS," AB Science CEO Alain Moussy said in a statement.

AB Science has reached this point before with masitinib in other indications. In recent years, EMA has knocked back applications to approve masitinib in gastrointestinal and pancreatic cancer. On both occasions, the regulator took issue with aspects of the clinical trial design, safety and production of masitinib. In 2014, AB Science sought to quell concerns about its production practices by stating that impurities were adequately controlled and its operation was compliant with ICH guidelines.

While the latest study may well be free of the issues that led to the earlier rejections, the cycle of positive press releases followed by regulatory knockbacks that characterized the development of masitinib in gastrointestinal and pancreatic cancer has contributed to AB Science's pronouncements facing particular scrutiny. In the case of the release to unveil ALS data, a lack of detailed information about the efficacy of masitinib--or its safety, a factor regulators have questioned in the past--leaves it open to skeptical responses.

This week, many investors were willing to overlook such concerns. If the ALS data stand up to the scrutiny of regulators, they could provide vindication of AB Science's relatively scattergun approach to drug development. Clinical trials of masitinib in a laundry list of indications have, to date, failed to deliver data capable of winning approval for use in humans. Now, with the ALS release following on from Phase III data in severe systemic mastocytosis, AB Science is once again on the cusp of finding out what regulators make of masitinib. 

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