Saturday, June 03, 2023
Theratechnologies Inc. (TSX: TH) (NASDAQ: THTX), a biopharmaceutical company focused on innovative treatments, announced today that the U.S. Food and Drug Administration (FDA) has approved a protocol amendment for its Phase I clinical trial of sudocetaxel zendusortide. Sudocetaxel zendusortide is an investigational peptide-drug conjugate (PDC) designed to target the Sortilin receptor (SORT1) and enhance the delivery of a cytotoxic payload to cancer cells.
The FDA's acceptance of the protocol amendment also signifies the removal of the partial hold that was placed on the Phase I trial following a voluntary pause in patient enrollment by Theratechnologies in December 2022.
The revised trial protocol, submitted to the FDA in May 2023, aims to clarify the therapeutic window of sudocetaxel zendusortide and extend the treatment duration. Changes include adjusting the dosing frequency to once weekly and focusing on a specific patient population with high-grade serous ovarian cancer, high-grade peritoneum or fallopian tube cancer, and high-grade endometrioid cancer. The refinement in patient selection will prioritize individuals with fewer prior treatments.
Dr. Christian Marsolais, Senior Vice President and Chief Medical Officer of Theratechnologies, expressed satisfaction with the FDA's approval of the protocol update. He highlighted the collaborative efforts between the Scientific Advisory Board and the FDA in reaching an agreement on the protocol modifications. The company believes that these changes will expedite the development of sudocetaxel zendusortide, providing a targeted and effective treatment option for advanced cancer patients while minimizing toxicity.
The amended study will follow a modified type 6 + 6 design, with two different dosing regimens falling within the established efficacy range for sudocetaxel zendusortide. The trial will initially enroll at least six patients to receive a weekly dose of 1.75 mg/kg on days 1, 8, and 15 of a 28-day cycle. Subsequently, an additional six patients will be enrolled to receive a dose of 2.5 mg/kg on the same schedule. The study will evaluate dose-limiting toxicities (TLDs) during a three-month observation period for the initial dose. If the trial demonstrates safety (0 or 1 TLD), six more patients will be enrolled to receive the higher dose. After a second three-month observation period, four additional patients will be recruited, bringing the total number of patients in Part 3 of the trial to 16. The protocol amendments also allow for an expansion phase, which will include patients with certain types of difficult-to-treat tumors that have shown antitumor activity with sudocetaxel zendusortide.
Importantly, the revised protocol introduces a switch from body surface area dosing to weight-based dosing, providing more precise dosing and reducing toxicity for each participant.
Preliminary safety and efficacy data from Part 1 (increased dose) and Part 2 (dose expansion) of the phase I trial will be presented in a poster session at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago on June 3. Additionally, on June 13, Theratechnologies will hold a videoconference with investors and analysts, during which investigators from the phase I trial will provide further details about the ASCO data and the protocol modifications.
Theratechnologies' SORT1+™ technology platform serves as the basis for developing peptide-drug conjugates (PMCs) that target the Sortilin receptor (SORT1). SORT1 is expressed in various tumor types and is associated with aggressive disease and poor prognosis, making it an attractive target for anticancer therapies. Sudocetaxel zendusortide, one of the first PDCs developed using this platform, utilizes a cleavable linker to conjugate a proprietary peptide to docetaxel, a well-established cytotoxic chemotherapeutic agent. Sudocetaxel zendusortide has received Fast Track Designation from the FDA for the treatment of relapsed advanced solid tumors expressing Sortilin that are refractory to standard therapy. The compound is currently being evaluated in a phase I clinical trial.