Zentalis Pharmaceuticals and Pfizer have announced plans to commence a Phase I/II clinical trial of ZN-c3 to treat BRAF V600E-mutated metastatic colorectal cancer (mCRC) patients.

This trial is part of a strategic partnership between the companies announced earlier, along with a $25m equity investment from Pfizer in Zentalis.

The dose escalation study will analyse ZN-c3, along with the standard of care comprising encorafenib and cetuximab in mCRC patients.

Called the BEACON regimen, the standard of care treatment is approved by the US Food and Drug Administration (FDA).

A product candidate of Zentalis, ZN-c3 is a selective Wee1 inhibitor which could elicit synthetic lethality in cancer cells.

According to preclinical research, there exists evidence that supports the rationale for combining BRAF, Wee1, and EGFR inhibitors. 

In mutationally driven cancers, inhibition of Wee1 demonstrated synergy with various targeted agents. 

In a cell-line-derived xenograft (CDX) model, adding ZN-c3 to encorafenib and cetuximab boosted anti-tumour activity. 

The company plans to begin subject enrolment in the trial in the first quarter of next year.

Zentalis chief medical officer Carrie Brownstein said: “Combining ZN-c3 with the BEACON agents in this study represents an opportunity in our ZN-c3 clinical development programme, alongside ongoing studies in both the monotherapy and chemotherapy combination settings in multiple tumour types. 

“If successful in clinical trials and approved, the combination of ZN-c3 with targeted/DNA damage response (DDR) agents could be another potential treatment option to help improve the lives of people living with BRAF-mutated metastatic colorectal cancer.”

In April last year, the company entered a clinical partnership agreement to assess the combination of ZN-c3 with GlaxoSmithKline’s (GSK) Zejula (niraparib) for advanced epithelial ovarian cancer.