French biotech's pain treatment fails Phase 2 study due to effective placebo

AlgoTherapeutix, a biotech company based in Paris, recently faced a setback with its topical non-opioid drug, ATX01, which did not perform as expected in a mid-stage trial. The trial, known as the Phase 2 ACT study, involved 276 patients experiencing chemotherapy-induced peripheral neuropathy. Unfortunately, the drug failed to show a significant reduction in pain compared to a placebo. Both the treatment and placebo groups demonstrated an improvement of approximately 1.5 points on the numerical pain rating scale, according to CEO Stéphane Thiroloix, who discussed the results in an interview.

The company aimed for a difference of around one point between the treatment and placebo groups. However, an unexpectedly strong response from the placebo group prevented this target from being achieved. The reasons behind the high placebo effect remain unclear, although Thiroloix speculated it could relate to patient interactions at the trial sites or random occurrences. Nonetheless, he noted the absence of a consistent pattern across poorly and well-performing placebo sites.

Despite these challenges, AlgoTherapeutix remains optimistic about further developing ATX01. A post hoc analysis of the data from trial sites with lower placebo performance revealed that the 15% concentration of ATX01 demonstrated statistically significant superiority over placebo in several primary and secondary endpoints. Moreover, the drug was generally well tolerated, with most side effects being temporary and related to the skin.

Looking ahead, the company plans to conduct another double-blind study targeting the same patient population, focusing on the 15% concentration of ATX01. This new trial will incorporate strategies to minimize the placebo effect, such as a placebo run-in phase or an enrichment design. Thiroloix indicated that the decision of whether this trial will be classified as Phase 2 or Phase 3 will be made in consultation with the FDA.

Two years ago, AlgoTherapeutix secured €20 million in a Series B funding round to support the Phase 2 study. Moving forward, the company intends to discuss the recent trial results with potential partners with whom they have been in contact for the past two years. The outcome of these discussions will determine whether AlgoTherapeutix will collaborate with a partner for further development or seek additional funding to pursue the project independently.

ATX01 is a topical formulation derived from the tricyclic antidepressant amitriptyline, which functions by inhibiting sodium channels. Notably, in January, another drug targeting sodium channels, Vertex’s Journavx, received FDA approval for treating moderate-to-severe acute pain.

In conclusion, while the recent trial of ATX01 did not meet expectations, AlgoTherapeutix remains committed to exploring the potential of their drug. With plans for further studies and strategic discussions with potential partners, the company is actively seeking a path forward in the development of this promising treatment for chemotherapy-induced pain.