F-star Therapeutics to Present FS222 Trial-in-Progress Update at ESMO Immuno-Oncology Congress 2021

First-in-Human Study of Company’s CD137/PD-L1 Tetravalent Bispecific Antibody Expands into Tumor Specific Indications

CAMBRIDGE, United Kingdom and CAMBRIDGE, Mass., Dec. 07, 2021 (GLOBE NEWSWIRE) -- F-star Therapeutics, Inc. (NASDAQ: FSTX), a clinical-stage biopharmaceutical company dedicated to developing next generation bispecific immunotherapies to transform the lives of patients with cancer, today announced that the Company will present a trial-in-progress update on FS222, a CD137/PD-L1 mAb² bispecific antibody, at the European Society of Medical Oncology Immuno-Oncology (ESMO-IO) Congress 2021, taking place online only, December 8-11, 2021.

The poster, entitled “A First-in-Human Study of FS222, a CD137/PD-L1 tetravalent bispecific antibody, in patients with advanced malignancies” is presented by Dr. Elena Garralda of the Vall D’Hebron Institute of Oncology, Barcelona, Spain, and describes the design of a first-in-human Phase 1 multi-center, multi-part, open label study to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity and clinical activity of FS222 in adult subjects with advanced malignancies (NCT04740424). The poster may be viewed on the F-star website here.

FS222 targets PD-L1, the immune checkpoint protein that regulates the balance of activated T cells in the immune system and is overexpressed on many solid tumors, and CD137, a co-stimulatory molecule from the tumor necrosis factor receptor superfamily (TNFRSF), which is widely known to be upregulated on tumor-reactive CD8⁺ T cells or “killer T cells”. Currently, only a minority of patients have been observed to have long-lasting clinical benefit from therapies that block only the PD-(L)1 pathway.

The clinical study comprises an Accelerated Dose Titration (ADT) component followed by a 3+3 dose escalation design and dose expansion cohorts (Part A). Part B consists of tumor specific efficacy expansion cohorts. Enrollment is ongoing at four sites including Vall D’Hebron Institute of Oncology (VHIO), Barcelona, Hospital Universitario 12 de Octubre (Madrid); South Texas Accelerated Therapeutics (START), Hospital Universitario Fundación Jimenéz Díaz, Madrid; and Clinica Universidad de Navarra (CUN), Pamplona. The accelerated dose titration component of Part A was completed successfully, and identification of optimal patient groups, dose and schedule is on-going.