Senhwa Biosciences has filed several Investigational New Drug (IND) applications with the US Food and Drug Administration (FDA) and Health Canada, for its investigational drug CX-5461 to treat BRCA2 or PALB2 mutation positive solid tumours.

The clinical-stage biopharmaceutical firm is focused on developing next-generation DNA Damage Response (DDR) therapeutics for the treatment of cancer.

Its CX-5461 is designed to stabilise DNA G-quadruplexes of cancer cells and facilitates disruption of the replication fork in cancer cells.

Senhwa Biosciences chief medical officer John Soong said: “This IND submission is a key milestone in the clinical development of CX-5461. In a phase I study conducted by Senhwa’s clinical partner, Canadian Cancer Trial Group (CCTG), CX-5461 demonstrated clinically meaningful and lasting benefits in patients with specific tumour biomarkers that were resistant to platinum and other chemotherapeutics. The US and Canada clinical trials are being designed to further confirm the efficacy seen.”

CX-5461 works together with Homologous Recombination (HR) pathway deficiency

CX-5461 works together with Homologous Recombination (HR) pathway deficiency, including BRCA1/2 mutations, resulting in replication forks stall, DNA breaks and death of cancer cells.

Because of the defect in DNA repair, BRCA1/2 deficient tumour cells are said to show enhanced sensitivity to the PARP inhibitor (PARPi) through the mechanism of synthetic lethality, where more than 40% of BRCA1/2-deficient patients do not respond to PARPi.

In combination with HRD tumours, CX-5461 can be used through a synthetic lethality approach, to target DNA repair defects in HRD tumours, stated the company.

The company said that its drug has recently received PCF-Pfizer Global Challenge Award, and will be used in combination with Pfizer’s PARPi Talazoparib to specifically explore the therapeutic potential in prostate cancer.

In 2016, a winner of the Stand Up to Cancer’s Dream Team Grant studied CX-5461 in its Phase 1 study, and presented the study results at the 2019 annual San Antonio Breast Cancer Symposium.

Senhwa Biosciences CEO Tai-Sen Soong said: “CX-5461 is a first-in-class G-quadruplex stabilizer within a novel class of therapy that accelerates dsDNA breaks and has proven human efficacy across certain tumour types.

“We believe CX-5461 has great potential as a therapeutic for patients who have developed resistance to PARPi or other chemotherapies. This continues to be an unmet medical need in cancer treatment.”