A phase 2 trial of Indivior Pharmaceuticals’ opioid use disorder (OUD) candidate has missed its primary endpoint. Indivior ended internal development of the molecule and dropped another asset, actions that the company’s chief scientific officer said may have a “significant impact” on the R&D organization.
The phase 2 trial compared three doses of an orexin-1 receptor antagonist, which Indivior acquired for about $20 million in 2023, to placebo. On an earnings call Thursday, Indivior CSO Christian Heidbreder, Ph.D., said the study of INDV-2000 missed its prespecified primary endpoint of no treatment failure over 12 weeks when evaluated across the full dose range.
Indivior responded to the data by ending plans to develop INDV-2000 internally. Yet Heidbreder said the asset is “a credible business development opportunity,” reflecting signals detected in the phase 2 study.
Interpretation of the overall dose response was confounded by the “unanticipated underperformance” of the top, 400-mg, dose and a higher-than-anticipated placebo response, Heidbreder said.
Other cohorts were more encouraging. A prospectively planned sensitivity analysis, plus supportive findings, revealed “a credible and biologically coherent signal” at the 200-mg dose, the CSO added.
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At that dose, Heidbreder said Indivior saw higher abstinence rates versus placebo across cocaine and polysubstance use. The findings are exploratory, the CSO said, but “they are directionally consistent with the underlying orexin-1 mechanism and its potential role in cue-driven drug seeking, stress reactivity and relapse vulnerability.”
Indivior plans to strengthen the data package through additional analysis, including exposure-response work and further evaluation of supportive clinical and mechanistic findings. Beyond that, the company will pull the plug on INDV-2000 and look for a partner willing to invest to further explore the signal.
The company disclosed the decision alongside news that it has dropped plans to advance INDV-6001, a sustained-release prodrug of buprenorphine, into phase 3 in OUD. Indivior is returning the rights to the asset to Alar Pharmaceuticals, which outlicensed the candidate for $10 million upfront in 2023.
Heidbreder said the decisions about the two programs “are expected to have a significant impact on the R&D organization.” Indivior has yet to share details of the impact, but CEO Joe Ciaffoni discussed the potential for the company to “derive savings from the restructuring in R&D” in response to an analyst’s question.
