Senhwa Biosciences, Inc., a clinical-stage biopharmaceutical company focused on next-generation DNA Damage Response (DDR) therapeutics for the treatment of cancer, recently announced that it has submitted multiple Investigational New Drug (IND) applications to the U.S. Food and Drug Administration (FDA) and Health Canada evaluating its investigational drug, CX-5461, for the treatment of patients with solid tumours with BRCA2 or PALB2 mutations.

"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 tumor biomarkers that were resistant to platinum and other chemotherapeutics. The US and Canada clinical trials are being designed to further confirm the efficacy seen," said Dr John Soong, Chief Medical Officer of Senhwa Biosciences.

CX-5461 was recently named as a PCF-Pfizer Global Challenge Award recipient. Specifically, it will be used in combination with Pfizer's PARP inhibitor (PARPi), Talazoparib, to explore the therapeutic potential in prostate cancer, which is the second-leading cause of cancer death for men in the United States. In 2016, a recipient of the Stand Up to Cancer's Dream Team Grant selected CX-5461 to study in their Phase I trial. This study's clinical findings were featured in a spotlighted presentation at the 2019 annual San Antonio Breast Cancer Symposium. Due to the DNA repair defect, BRCA1/2 deficient tumour cells are more sensitive to PARPi through the mechanism of synthetic lethality. However, PARPi resistance is ubiquitous in clinic. More than 40% of BRCA1/2-deficient patients fail to respond to PARPi.

"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 PAPRi or other chemotherapies. This continues to be an unmet medical need in cancer treatment," said Dr Tai-Sen Soong, CEO of Senhwa Biosciences.

CX-5461 is designed to stabilize DNA G-quadruplexes of cancer cells and leads to disruption of the cell's replication fork. While acting in concert with Homologous Recombination (HR) pathway deficiency, such as BRCA1/2 mutations, replication forks stall and cause DNA breaks, resulting in cancer cell death. CX-5461 in combination with Homologous Recombination Deficiency (HRD) tumours may be exploited through a synthetic lethality approach, targeting DNA repair defects in HRD tumours.