Intra-Cellular's unstoppable Caplyta nails another trial

Intra-Cellular Therapies’ atypical antipsychotic medication Caplyta has been on a roll, delivering fast commercial growth and coming up triumphant in yet another late-stage trial.

In a statistically significant showing, treatment with Caplyta led to a longer time to relapse than placebo in schizophrenia patients, Intra-Cellular said Tuesday, citing top-line results from a phase 3 trial.

Caplyta showed a 63% reduction in the risk of relapse versus placebo during a 26-week double-blind treatment phase, according to the company. Eighteen relapses (a rate of 16.4%) occurred in the Caplyta group versus 44 incidents (38.6%) in the placebo group.

Besides meeting its primary endpoint of time to relapse, the trial, dubbed Study 304, also met a key secondary endpoint, linking Caplyta to better treatment discontinuation rates during the double-blind phase.

The data “support the continued long-term treatment with” Caplyta, Suresh Durgam, M.D., chief medical officer of Intra-Cellular, said in a statement Tuesday.

Caplyta won its initial FDA approval to treat schizophrenia in late 2019. Before the nod, Caplyta had shown statistically significant reductions on the Positive and Negative Syndrome Scale—a clinician-administered rating scale of schizophrenia symptoms—versus placebo in two separate trials.

Study 304, known as a “withdrawal trial,” is part of Intra-Cellular’s post-marketing commitment to the FDA, which is typical for antipsychotics. During the double-blind phase, patients whose disease was already stabilized after treatment with Caplyta were randomized to either continue on the active drug or switch to placebo for up to 26 weeks.

With approvals in schizophrenia and bipolar depression, Caplyta sales grew 39% year over year to $175 million in the third quarter, slightly ahead of analysts’ expectations. The growth rate outpaced the 4% increase by the entire branded antipsychotic market, Intra-Cellular Chief Commercial Officer Mark Neumann noted during a conference call last week.

Meanwhile, Intra-Cellular investors are highly focused on a potential expansion of Caplyta into major depressive disorder (MDD). After two positive phase 3 trials, Study 501 and Study 502, Intra-Cellular is preparing to file for an FDA approval in adjunctive MDD this year.

There are more than 30 million adults in the U.S. with either bipolar depression or MDD, according to the company. An adjunctive MDD indication would increase Caplyta’s total addressable market from nearly 50% of antipsychotic prescriptions for those disorders to nearly 80%, Neumann said on the call.

Given the momentum of Caplyta, Intra-Celllular during the third quarter added 150 new sales reps to better target primary care physicians. A second wave of sales force expansion is planned for 2025 in connection with the potential MDD nod, according to Neumann.

To further bolster Caplyta’s clinical profile in MDD, Intra-Cellular is running Study 503, an open-label rollover study to assess long-term safety in MDD.

Following the two recent successful phase 3 studies, Intra-Cellular a few days ago amended the eligibility criteria for yet another study, Study 505, to gather more data in patients who’ve had an inadequate response to a greater number of antidepressants. The objective is “to further expand the large body of evidence supporting [Caplyta] antidepressant efficacy across different patient populations,” the company explained in its quarterly filing.