Canadian biotech narrows trial population to lift solid tumor drug out of FDA hold

The FDA has signed off on an amended trial protocol for Theratechnologies’ solid tumors medicine, lifting its clinical hold and setting the Canadian biotech free to proceed.

The phase 1 study for TH1902, also known as sudocetaxel zendusortide, has been on pause since December 2022, when Theratechnologies got a glimpse at initial data that showed the drug's efficacy did not outweigh its risks. The company reported adverse events, mainly neuropathy and eye toxicity, and halted enrollment on its own. The FDA later placed a hold on the study.

Now, the trial can proceed, according to a Friday press release from Theratechnologies. Last month, the company provided the FDA with its plans for the amended protocol, which aims to improve the therapeutic window of sudocetaxel zendusortide and extend its duration.

The patient population has been narrowed to just those patients with high-grade serous ovarian cancer with a particular focus on those who have not been heavily pretreated. Patients should not have had more than one taxane failure and a maximum of eight prior lines of treatment. The company said that sudocetaxel zendusortide has shown preliminary efficacy in this population already.

Previously, the early-stage study was enrolling 70 participants with a range of solid tumors and cancers. Theratechnologies creates cancer therapies targeting receptors of the SORT1 protein, which are expressed in 40% to 90% of endometrial, ovarian, colorectal, triple-negative breast and pancreatic cancers.

In February 2021, the FDA granted fast-track designation to sudocetaxel zendusortide as a single agent for the treatment of all sortilin-positive recurrent advanced solid tumors that are refractory to standard therapy.

Dosing has also been changed to weekly to provide a more precise measurement and minimize adverse events, Theratechnologies Chief Medical Officer Christian Marsolais, Ph.D., said in the release.

“Based on our pharmacokinetic and pharmacodynamic analyses, we decided to switch from body surface area dosing to an equivalent weight-based dosing so we could provide a more precise dose and minimize toxicity for each trial participant,” Marsolais said.

Early results from part 1 and 2 of the phase 1 study were presented in a poster session at the American Society of Clinical Oncology on Saturday.