Actinogen Medical’s cortisol blocker has missed the primary endpoint of a phase 2 study in depression, leaving the Australian biotech to focus on its potential in Alzheimer’s disease.
The drug, called xanamem, blocks the 11β-HSD1 enzyme in order to halt the excess production of the stress hormone cortisol in brain cells. Today’s results came from a phase 2 study of 167 patients with cognitive dysfunction and major depressive disorder who received xanamem 10 mg or placebo over six weeks.
The XanaCIDD study’s primary endpoint was a composite of computerized tests of attention and memory. Investigators recorded similar 0.3-point and 0.4-point improvements in the xanamem and placebo groups, respectively.
The company speculated that this “unexpectedly large placebo mean improvement may have impaired the ability of the trial to observe any short-term pro-cognitive effects of xanamem.”
Actinogen’s stock plummeted 60% on Monday in the wake of the news, although the biotech’s previously low share price meant the difference was negligible. The company’s stock ended trading on the Australian Securities Exchange today at 3 Australian cents compared to a Friday trading price of 7 cents.
Rather than focus on the failure, Actinogen’s leadership tried to find the positives in the data, including a “clinically significant” 1.5-point improvement in the MADRS depression score at six weeks for patients who received xanamem compared to placebo. The 2.7-point improvement seen at just four weeks was “statistically significant,” the company pointed out.
The biotech also zoomed in on a subgroup of 81 patients with less severe depression, who saw a 3.6-point improvement in their MADRS score after the end of treatment.
“This encouraging result on depression is very positive to the whole xanamem program and confirms 10 mg daily is an active clinical dose with the ability to potentially modify underlying biological processes in the brain,” Actinogen Chief Medical Officer Dana Hilt, M.D., said in the release.
“We will continue to examine these topline data in detail and the larger dataset to better understand the complete results and determine next steps for the depression program,” Hilt added. “The unexpected cognition placebo effect appears to have impaired the ability of xanamem to show the pro-cognitive effects that we have observed in three previous studies.”
CEO Steven Gourlay stressed in the same release that the company’s “primary objective” remains an ongoing phase 2b trial assessing xanamem’s ability to slow or halt Alzheimer’s progression over 36 weeks.
The biotech noted that the Alzheimer’s trial will not be using the same cognitive measurements that sunk today’s depression study, instead focusing on a “broader range of tests.”
“I believe the results on acute symptomatic cognitive enhancement in XanaCIDD do not alter the chances of success for xanamem in Alzheimer’s disease where cortisol is implicated in the underlying biology of long-term disease progression reflected as functional and cognitive decline,” Hilt added in the release.