Carrick Therapeutics has entered a clinical trial collaboration and supply agreement with Arvinas and Pfizer to evaluate samuraciclib (CT7001) along with vepdegestrant (ARV-471) for the treatment of advanced breast cancer.

The potential of the combined therapy will be evaluated in a Phase Ib/II clinical trial anticipated to begin in the second half of this year.

The study will assess Carrick’s oral CDK7 inhibitor samuraciclib combined with Arvinas’ vepdegestrant, an investigational oral PROteolysis Targeting Chimera (PROTAC) estrogen receptor protein degrader being developed in partnership with Pfizer.

Patients with estrogen receptor-positive (ER+) or human epidermal growth factor receptor 2 negative (HER2-) metastatic breast cancer and who have previously received CDK4/6i will be enrolled.

Arvinas will act as the regulatory sponsor of the trial in the US while Pfizer will be the acting sponsor. Outside the US, Pfizer will act as both a regulatory and acting sponsor.

Carrick Therapeutics CEO Tim Pearson said: “Despite the significant progress made in oncology in recent years, the treatment of HR+ breast cancer continues to have considerable unmet needs.

“We are encouraged by the initial clinical trial data from vepdegestrant and believe there could be potential synergies when combining it with samuraciclib.”

Vepdegestrant, when dosed as a single agent in several ER-driven xenograft models, induced tumour shrinkage, in pre-clinical trials. It also demonstrated up to 97% ER degradation in tumour cells.

Arvinas and Pfizer signed a global collaboration in July 2021 to co-develop and co-commercialise vepdegestrant.

Both will equally share global commercialisation expenses, profits, and development costs.