Liver tox cases force Daiichi Sankyo to curtail recruitment for PhIII trial of a ‘breakthrough’ drug

Two cases of serious liver toxicity forced investigators to suspend enrollment on Daiichi Sankyo’s Phase III program for its “breakthrough” drug pexidartinib (PLX3397). But both cases were non-fatal, a company spokesperson tells Endpoints News, and the trial is headed to completion after the company decided to wrap enrollment a few subjects short of their goal.
Daiichi Sankyo is testing the drug on rare cases of tenosynovial giant cell tumor (TGCT) among patients who couldn’t qualify for surgical removal of the tumor. By the time the liver tox issues appeared, the company had already enrolled 121 of the planned 126 patients and the data monitoring committee suggested cutting enrollment short and taking measures so they could preserve the study as a double-blinded test.
“As a result,” Daiichi said in a statement to Endpoints, “ENLIVEN will continue to completion in order to evaluate its efficacy and safety endpoints. These measures were reviewed and agreed on by the U.S. Food and Drug Administration (FDA), and all regulatory authorities involved in the ENLIVEN study have been notified. All patients currently enrolled in ENLIVEN are in the process of being informed about this updated safety information and will undergo re-consent for continued participation in the study.”
Daiichi Sankyo won the FDA’s breakthrough therapy designation for the oral CSF-1R inhibitor based on its Phase I results posted last summer. The same trial persuaded the Japanese pharma company to move straight into Phase III. That’s an increasingly common clinical trial strategy.
“Surgery is the primary treatment for TGCT, but for patients with a diffuse form of the condition, the tumor is more difficult to remove and has a high rate of recurrence, resulting in multiple complicated surgeries and even amputation in some patients,” noted Mahmoud Ghazzi, Daiichi Sankyo’s former R&D chief, last summer. Ghazzi left the company last month.