BioPharma

Clinical trials of Allergan’s antidepressant rapastinel fail

An analyst said the news could negatively affect shares of a successor to the company that developed rapastinel - which Allergan bought in 2015 - given that its drugs belong to the same class.

Sad face depression

An investment by Allergan of more than half a billion dollars appears not to have paid off.

The Dublin-based drugmaker said Wednesday that the three clinical trials of rapastinel, as an adjunctive treatment for major depressive disorder, did not show superiority over placebo. Shares of the company fell throughout the day, opening down 3.3 percent Thursday morning on the New York Stock Exchange before sharply rising 5.3 percent. The company had announced before markets opened Thursday morning that the Food and Drug Administration accepted its supplemental approval application for Botox as a treatment for children with upper and lower limb spasticity.

The three studies – RAP-MD-01, -02 and -03 – measured change over a three-week period in baseline measurements on the Montgomery-Asberg Depression Rating Scale, or MADRS, at the end of the study as their primary endpoints, according to ClinicalTrials.gov. Change in baseline in the MADRS total score was used as the secondary endpoint. The three trials had similar designs – being double-blind and placebo controlled – except one had an additional treatment arm that evaluated a different dose level of the drug.

The announcement coincided and contrasted with better news from Johnson & Johnson’s Janssen subsidiary, which announced the approval of Spravato (esketamine), a ketamine-derived drug that is the first antidepressant with a novel mechanism of action in decades.

In a note to investors Thursday, SVB Leerink analyst Geoffrey Porges and colleagues pointed out also that the failure of the drug may not bode well for another company, Aptinyx. They explained that Aptinyx’s shares could be adversely affected because the role in rapastinel’s discovery and development played by predecessor company Naurex before that company’s 2015 acquisition by Allergan for $560 million. Many investors, they wrote, viewed Allergan’s acquisition of rapastinel as an important validation of the company, and the drug’s failure could lead investors to discount the potential of Aptinyx’s clinical programs despite differences in indications.

Aptinyx’s pipeline includes three drugs in clinical development that are NMDA receptor modulators, with the same mechanism of action as rapastinel. They are NYX-2925, in Phase II studies for diabetic peripheral neuropathy and fibromyalgia; NYX-783, in Phase II development for post-traumatic stress disorder; and NYX-458, in Phase I development for cognitive impairment related to Parkinson’s disease.

Following Allergan’s announcement, Aptinyx’s shares had fallen 17 percent on the Nasdaq as of early afternoon Friday.

Photo: Phototechno, Getty Images

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