Axsome’s oral drug AXS-05 provided statistically significant improvements in patients with major depressive disorder (MDD).

Anti-depression medications can be difficult to evaluate in clinical trials owing to their placebo effect. In its mid-stage ASCEND clinical study, Axsome got around this difficulty by comparing its candidate AXS-05, the formulation of which includes dextromethorphan (DM) and bupropion, to changes in 80 MDD patients taking bupropion alone. The patients received treatment for 6 weeks, and their scores on the Montgomery–Åsberg depression rating scale were determined throughout the treatment period.

Early results are very encouraging. Patients on the combination drug experienced a statistically significant reduction on the Montgomery–Åsberg depression rating scale averaged over the 6-week treatment period, compared with those taking bupropion alone. Notably, patients were observed to begin to experience improvements from the first week, with statistically significant improvement beginning in week 2. AXS-05 was also shown to be superior across all secondary endpoints with a similar rate of adverse events and without any weight gain or sexual dysfunction side effects, which are common with many antidepressants.

The oral candidate is also being evaluated in a phase III study (STRIDE-1) for treatment-resistant depression (TRD).