Addex-J&J Epilepsy Drug Flops in Phase II, Considers Next Steps

Addex Therapeutics and Johnson & Johnson's (J&J) Janssen Pharmaceuticals have reported that ADX71149, a compound being studied for its potential in treating epilepsy, failed to meet its main goal in a Phase II clinical trial. The drug, which is an investigational modulator of the metabolic glutamate subtype 2 receptor, did not demonstrate a statistically significant improvement in the time it took for patients to return to their baseline seizure frequency when used alongside standard treatments.

The study, which was randomized, double-blinded, and placebo-controlled, involved 110 participants with focal onset seizures who had not responded well to levetiracetam or brivaracetam. The primary endpoint was the time to reach baseline seizure count, but the trial did not show a significant difference between ADX71149 and the placebo.

While the drug did not outperform the placebo in terms of efficacy, both companies noted that ADX71149 was safe and well-tolerated by the patients in the study. The compound is designed to regulate the neurotransmitter balance in the brain, which could potentially decrease the occurrence of seizures in epilepsy patients.

Despite the setback, Addex will continue to analyze the trial data and is expected to release more detailed findings once the analysis is complete. The company is also working with Janssen to determine the next steps for the ADX71149 program.

The partnership with J&J has been crucial for the development of ADX71149, with Janssen taking on the responsibility for the drug's development. The trial was initiated in June 2021, and the final patient was enrolled in September 2023. According to the agreement, Addex is eligible to receive up to approximately $117 million in milestone payments based on the success of the development and regulatory process, as well as royalties on net sales.

In light of the Phase II study's results, Addex CEO Tim Dyer has indicated that the company will now concentrate on advancing its other drug programs, such as the GABAB PAM program in partnership with Indivior, which is aimed at treating substance use disorder and chronic cough. The company is also focused on the development of dipraglurant, a negative allosteric modulator of the metabotropic glutamate receptor subtype 5, for post-stroke sensorimotor recovery.

The failure of ADX71149 in the Phase II trial underscores the challenges faced in drug development, particularly in the complex field of epilepsy treatment. It highlights the importance of continued research and development efforts to find effective treatments for this condition.