KSQ Therapeutics Announces First Patient Dosed in Clinical Development Program for KSQ-001EX, a CRISPR/Cas9 Engineered Tumor Infiltrating Lymphocyte (eTIL®) Therapy

Lexington, Mass., June 12, 2024 — KSQ Therapeutics, Inc. (KSQ), a clinical-stage biotechnology company developing treatments for solid tumors, today announced the first patient dosed in the Phase 1/2 clinical study of KSQ-001EX, a novel edited TIL therapy. KSQ-001EX consists of TIL in which the SOCS1 gene is inactivated by CRISPR/Cas9 gene editing, giving it the potential to be a best-in-class treatment for a variety of solid tumor indications. KSQ's CRISPRomics^® platform identified SOCS1 as a key gene inhibiting T cell growth, survival, and differentiation by negatively regulating cytokine signaling in the tumor microenvironment.

"TIL have emerged as a powerful new treatment modality, and we believe both of our eTIL® programs, KSQ-001EX and KSQ-004EX, have the potential to significantly advance the field by improving the potency of TIL therapy for the treatment of a variety of solid tumor types. In preclinical studies, KSQ-001EX demonstrated enhanced anti-tumor activity, polyclonality, persistence, and memory formation in multiple solid tumor models compared to unmodified TIL. We also saw robust anti-tumor activity in models insensitive to PD-1 inhibition,” said Qasim Rizvi, Chief Executive Officer of KSQ. “We look forward to evaluating KSQ-001EX in patients with difficult-to-treat solid tumors, including melanoma, head and neck squamous cell carcinoma, and non-small cell lung cancer.”

The first patient treated with KSQ-001EX was enrolled by Rodabe Amaria, M.D., professor of Melanoma Medical Oncology and principal investigator of the study at The University of Texas MD Anderson Cancer Center.

Phase 1/2 Trial Design

The Phase 1/2 clinical trial is an open-label, safety lead-in study for patients with melanoma, head and neck squamous cell carcinoma (HNSCC), and non-small cell lung cancer (NSCLC). The primary objective of the Phase 1 portion of the trial is to evaluate the safety and tolerability of KSQ-001EX. In the safety lead-in portion, a cohort of patients will be initially dosed without IL-2. The primary objective of Phase 2 is to evaluate antitumor activity in indication-specific cohorts.

About KSQ-001EX

KSQ’s lead eTIL^® cell therapy program, KSQ-001EX, in which TIL are edited to inactivate the SOCS1 gene, has the potential to revolutionize the treatment of solid tumors. In preclinical studies, KSQ-001EX demonstrated enhanced anti-tumor function in solid tumor models refractory to PD-1 inhibition, as well as enhanced persistence and memory formation.

About KSQ Therapeutics

KSQ Therapeutics is advancing a pipeline of novel drug candidates to treat cancer across multiple drug modalities, including targeted therapies, adoptive cell therapies, and immunotherapies. KSQ's proprietary CRISPRomics^® discovery engine enables genome-scale insights driving novel therapeutic discovery. For more information, please visit the company's website at www.ksqtx.com.