AEON focuses on cash preservation after Phase II migraine drug setback

AEON Biopharma faced a significant setback on Friday as its stock plummeted due to disappointing interim results from a Phase II study of its lead candidate, ABP-450 (prabotulinumtoxinA), designed to prevent chronic migraines. The clinical trial failed to achieve its primary goal, resulting in a massive 55% drop in AEON's share price.

The central aim of the study was to measure the average reduction in monthly migraine days (MMD) over weeks 13 to 24. The study included 325 patients divided into three groups: a placebo group, a 150U ABP-450 group, and a 195U ABP-450 group. The results showed that the 150U and 195U ABP-450 groups achieved MMD reductions of 8.5 and 7.7 days, respectively, aligning with expectations. However, the placebo group unexpectedly saw an 8.4-day reduction, leading to no statistically significant difference between the active treatment and placebo groups.

None of the secondary endpoints met statistical significance either. AEON described the placebo response as "much higher than expected based on previous studies." CEO Marc Forth expressed the company’s surprise and disappointment, stating, "We are conducting additional analyses of the interim data to understand the highly abnormal and unexpected placebo effect and further evaluate the results of this study to determine the best path forward in the development of ABP-450 for the preventive treatment of migraine."

In response to these results, AEON has initiated immediate cash preservation measures and plans to review all strategic options moving forward. Analysts at H.C. Wainwright noted that AEON had previously aligned with the FDA on pivotal Phase III trials for ABP-450 aimed at both episodic and chronic migraines following a successful end-of-Phase I meeting.

This isn't the first time AEON has encountered issues with a high placebo response affecting the outcomes of an ABP-450 study. Last October, the company reported Phase II data for ABP-450 in treating episodic migraines. In that study, doses of 150 units and 195 units showed treatment effects of 4.8 days and 5 days, respectively, in the mean change from baseline in MMD at weeks 21 to 24. However, these results were not significantly better than the 4.2-day reduction observed with a placebo. Despite this, H.C. Wainwright analysts had suggested the treatment effect was substantial enough to justify continuing development beyond the placebo rate.

Besides its use in migraine prevention, ABP-450 is also undergoing Phase II testing for cervical dystonia, with plans for a Phase III trial later this year. Additionally, ABP-450 is in early-stage trials for gastroparesis.

The unexpected high placebo response observed in the current and previous trials raises questions about the viability of ABP-450 as a reliable treatment for migraines. AEON Biopharma must now conduct further analyses to fully understand the anomaly and decide the future course of action for ABP-450. The company's immediate steps toward cash preservation and strategic review indicate a cautious approach as it navigates this challenging situation.