Histogen seeks to tear up COVID-19 R&D pact and go solo, accuses Amerimmune of failing to push on into phase 2

The collaboration between Histogen and Amerimmune has soured. Believing Amerimmune has failed to meet its R&D responsibilities, Histogen is seeking to terminate the collaboration agreement and retake control of the COVID-19 development program.

Amerimmune signed up to work with Histogen, which merged with Conatus Pharma two years ago, on the development of pan-caspase inhibitor emricasan in COVID-19 in October 2020. In summarizing the deal, Histogen said Amerimmune is “required to use commercially reasonable efforts to lead the development activities for emricasan” in COVID-19. Histogen has accused Amerimmune of failing to hold up its end of the bargain.

“We believe that, for numerous reasons set forth in our arbitration demand, Amerimmune has failed to undertake commercially reasonable efforts towards the development of emricasan as required by the Collaborative Agreement. Therefore, we are currently seeking to terminate the Collaborative Agreement and independently proceed with the development of emricasan for the treatment of COVID-19 and other infectious and inflammatory diseases,” Histogen wrote in a financial filing.

Histogen provided a notice of material breach in relation to its claims in January before going on to file an arbitration demand earlier this month. In the demand, Histogen is seeking a declaratory judgment that Amerimmune has materially breached the agreement and, as such, it can terminate the deal. If that happens, Histogen plans to develop emricasan independently.

Whatever happens in arbitration, Histogen expects a phase 2 clinical trial to start in the second half of 2022. Amerimmune and Histogen presented top-line data from a phase 1 clinical trial of emricasan in mild symptomatic COVID-19 patients in June. The study found emricasan to be safe and well tolerated.

Since then, Merck and Pfizer have brought oral COVID-19 antivirals to market, providing new options for patients with mild to moderate symptoms. The authorizations and results supporting them, particularly the data generated by Pfizer, have reshaped the market and set the bar for subsequent candidates.