SEATTLE – January 5, 2024 - ProfoundBio, a clinical-stage biotechnology company developing novel antibody-drug conjugate (ADC) therapeutics for cancer, today announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation for rinatabart sesutecan (Rina-S; PRO1184), a folate receptor alpha (FRα) targeted ADC, for the treatment of patients with FRα-expressing high-grade serous or endometrioid platinum-resistant ovarian cancer.  Fast Track designation is intended to facilitate the development and expedited review of drugs with demonstrated potential to improve over available therapy for serious conditions with unmet medical need.

“Our receipt of Fast Track designation from the FDA underscores our belief in the tremendous promise of Rina-S as a potential best-in-class FRα ADC to address the significant need for improved treatment options for advanced ovarian cancer,” said Naomi Hunder, Chief Medical Officer of ProfoundBio. “FRα is a highly prevalent antigen in ovarian cancer and Rina-S has shown encouraging antitumor activity and tolerability in our Phase 1 dose escalation study in ovarian and endometrial cancer patients across the full spectrum of FRα expression. We look forward to working closely with the FDA as we progress further clinical development and registrational studies for Rina-S.”

About Rinatabart Sesutecan (Rina-S, PRO1184)

Rina-S is a folate receptor-alpha (FRα) targeted ADC being developed as a novel treatment option for patients with ovarian and endometrial cancer, and potentially other FRα-expressing cancers. Rina-S is comprised of a FRα-directed antibody conjugated to sesutecan, ProfoundBio’s novel, proprietary hydrophilic exatecan-based linker-drug, at a homogeneous drug-to-antibody ratio (DAR) of 8. Exatecan is a highly potent, membrane permeable topoisomerase-1 inhibitor with strong bystander effect. Sesutecan is a highly hydrophilic, stable, cleavable linker designed to mask the hydrophobicity of conjugated exatecan on the ADC, enabling high DAR and efficient delivery of the exatecan payload to tumors while maintaining favorable physicochemical and pharmacokinetic properties of the ADC.

Status of PRO1184-001 Phase 1/2 Study (NCT05579366)

PRO1184-001 is a Phase 1/2 study of rinatabart sesutecan to evaluate the safety, tolerability, PK, and antitumor activity of PRO1184 in patients with selected locally advanced and/or metastatic solid tumors, including epithelial ovarian cancer, endometrial cancer, breast cancer, non-small cell lung cancer, and mesothelioma. The study consists of two parts, Part A: Dose Escalation and Part B: Dose Expansion.  Initial results from Part A were reported in November 2023, demonstrating encouraging antitumor activity at well tolerated doses in heavily pretreated ovarian and endometrial cancer patients unselected for FRα expression.  Part B is currently enrolling patients at multiple sites in the U.S. and China.

About ProfoundBio

ProfoundBio is a clinical-stage biotechnology company focused on the development of novel antibody-based therapeutics with curative potential for patients with cancer. Built on internally developed, innovative, and proprietary technology platforms, ProfoundBio has developed a pipeline consisting of multiple antibody-drug conjugate (ADC) drug candidates targeting solid tumors and hematological malignancies. The company’s disclosed development pipeline consists of rinatabart sesutecan (Rina-S; PRO1184), an ADC targeting folate receptor-alpha; PRO1160, an ADC targeting CD70; PRO1107, an ADC targeting PTK7; and PRO1286, a bispecific ADC targeting two clinically validated, broadly expressed solid tumor antigens. ProfoundBio is headquartered in Seattle, Washington.

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