Novel Antidepressant Shines in Phase 2 Trial, but FDA Has Issues With Its NDA

Megan Brooks

August 11, 2021

Although a novel investigational drug that combines dextromethorphan and bupropion (AXS-05, Axsome Therapeutics) met its primary and key secondary endpoints in a phase 2 trial of patients with treatment-resistant depression (TRD), the US Food and Drug Administration (FDA) has voiced some concerns.

In the MERIT study, AXS-05 significantly delayed time to depression relapse compared with placebo (primary endpoint) — with no relapses observed for at least 6 months. It also significantly prevented depression relapse (secondary endpoint), the company said in a news release announcing the topline results.

The drug has been granted breakthrough therapy designations by the FDA for the treatment of major depressive disorder (MDD) and agitation associated with Alzheimer's disease.

In addition, the agency is currently reviewing a new drug application (NDA) for AXS-05 for the treatment of MDD, with a target action date of August 22.

However, Axsome said earlier this week that the FDA has identified "deficiencies that preclude labeling discussions at this time."

The company is "attempting to learn the nature of these deficiencies with the goal of addressing them," Herriot Tabuteau, MD, chief executive officer of Axsome, said in a statement.

However, Tabuteau acknowledged that this development "may lead to a delay in the potential approval of AXS-05."

"Well Tolerated"

A total of 44 adults with TRD were enrolled into the MERIT study from the long-term, open-label phase 3 trial of AXS-05.

All patients were in stable remission after treatment with AXS-05 and were randomly assigned to continued treatment with AXS-05 (45 mg dextromethorphan/105 mg bupropion twice daily) or to switch to placebo.

Compared with placebo, AXS-05 significantly delayed time to depression relapse (P = .002) and prevented depression relapse (P = .004).

The novel drug was also well tolerated, with no treatment-emergent adverse events reported in more than one participant in the AXS-05 group, the company said.

One patient treated with AXS-05 did experience gout and bacteremia, but these incidents were deemed unrelated to the medication.

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