On June 3, 2022 Sapience Therapeutics, Inc., a clinical-stage biotechnology company focused on the discovery and development of peptide therapeutics to address difficult-to-treat cancers, reported data from a Phase 1 study demonstrating efficacy proof-of-concept of the Company’s lead program, ST101, in patients with refractory solid tumors (Press release, Sapience Therapeutics, JUN 3, 2022, View Source [SID1234615517]). The data will be presented in a poster discussion session at the American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting in Chicago, IL on June 5, 2022.

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ST101, a first-in-class peptide antagonist of C/EBPβ, is currently being evaluated in the Phase 2 portion of an ongoing Phase 1-2 clinical study in patients with advanced unresectable and metastatic solid tumors (NCT04478279). The primary objectives of the Phase 1 clinical study were to evaluate the safety and tolerability of ST101 and to determine the recommended Phase 2 dose. Secondary and exploratory objectives included pharmacokinetics (PK), preliminary efficacy (RECIST 1.1), and pharmacodynamic (PD) evaluation. The study used a 3+3 dose-escalation design, with once-weekly IV infusion dosing of ST101 at 0.5, 1, 2, 4, 6, 9 mg/kg or a flat dose of 500 mg.

Phase 1 Study Results:

As of May 5, 2022, 25 patients with multi-metastatic disease that were refractory to standard therapy received a median of 8 weeks of treatment
Three patients show ongoing clinical benefit:
One confirmed PR lasting more than 51 weeks in a patient with cutaneous melanoma
Eight patients with varying histologies had stable disease lasting 9-81+ weeks (2 ongoing)
No DLTs, dose modifications, or serious adverse events (SAEs) related to ST101
Pharmacokinetics and pharmacodynamics support the selection of a 500 mg flat dose as the recommended Phase 2 dose
Dr. Alice Bexon, Sapience’s Chief Medical Officer, commented, "We remain extremely pleased with the safety and efficacy ST101 has demonstrated in Phase 1, with evidence of clinical benefit across the whole dose range explored, particularly at higher doses and in patients with melanoma. The Phase 2 expansion portion of the study is going very well, with all cohorts enrolling, and a confirmed partial response in a patient with recurrent glioblastoma, which is very exciting. We believe that ST101’s unique mechanism of action targeting C/EBPß represents a potentially transformative approach to treating cancer."

+indicates ongoing treatment

SD=stable disease
PR=partial response

Details of the poster presentation at ASCO (Free ASCO Whitepaper) 2022 are as follows:

Abstract Number: 3014
Title: Efficacy proof-of-concept from a phase 1 study of a novel therapeutic peptide, ST101, targeting the oncogenic transcription factor C/EBPβ in patients with refractory solid tumors
Session Title/Track: Developmental Therapeutics – Molecularly Targeted Agents and Tumor Biology
Session Type: Poster Discussion Session
Date/Time: June 5, 2022, 2:30 PM CDT

Abstracts and full session details can be accessed through the ASCO (Free ASCO Whitepaper) meeting planner: Abstracts | ASCO (Free ASCO Whitepaper) Annual Meeting

About ST101 and the Phase 1-2 Study
ST101, a first-in-class antagonist of C/EBPβ, is currently being evaluated in the Phase 2 portion of an ongoing Phase 1-2 clinical study in patients with advanced unresectable and metastatic solid tumors (NCT04478279). ST101-101 is an open-label, two-part, Phase 1-2 dose-finding study designed to determine the safety, tolerability, PK, PD, and proof-of-concept efficacy of ST101 in patients with advanced solid tumors. The study consists of two phases: Phase 1 dose escalation/regimen exploration and Phase 2 expansion. In the ongoing dose escalation study, ST101 has demonstrated clinical proof-of-concept with a durable RECIST 1.1-confirmed partial response (PR) in a patient with cutaneous melanoma and evidence of long-lasting stable disease in several additional patients. In the ongoing Phase 2 dose expansion part of the study, ST101 has demonstrated clinical proof-of-concept with a confirmed partial response in a patient with recurrent GBM. Sapience is actively enrolling patients with GBM, metastatic cutaneous melanoma, locally advanced or metastatic hormone-receptor positive breast cancer and castration-resistant prostate cancer. ST101 has been granted Fast Track designation for recurrent GBM and advanced cutaneous melanoma in patients who have disease progression on or after anti-PD-1/anti-PD-L1 therapy, as well as orphan designations from the FDA for advanced melanoma, glioma and AML, and from the European Commission for the treatment of glioma.