Pfizer and Arvinas to Develop and Commercialize Estrogen Receptor Targeting Breast Cancer

Pfizer and Arvinas announced in a July 22, 2021 press release a global collaboration to develop and commercialize ARV-471, an investigational oral PROTAC (proteolysis targeting chimeras) estrogen receptor (ER) protein degrader.

Pfizer will pay Arvinas $650 million upfront under the agreement and will make a $350 million equity investment in Arvinas. Worldwide development costs, commercialization expenses, and profits will be shared equally between the two companies.

In an ongoing Phase II dose expansion clinical trial, ARV-471 is being assessed for the treatment of patients with ER positive/human epidermal growth factor receptor 2 (HER2) negative (ER+/HER2-) locally advanced or metastatic breast cancer.

ER is the primary driver of hormone receptor positive breast cancer—the most common breast cancer subtype, according to the company. Endocrine therapy is used as monotherapy or as combination therapy across treatment settings as a standard form of care.

In December 2020, interim data indicated its potential as a novel oral ER targeted therapy from the ongoing Phase I dose escalation clinical trial of ARV-471 in patients with locally advanced or metastatic ER+/HER2- breast cancer. In addition, ARV-471 is being evaluated as a treatment for metastatic breast cancer in a Phase I dose escalation study, a Phase 1b combination study with Pfizer’s IBRANCE (palbociclib), and a Phase 2 monotherapy dose expansion study (VERITAC).

The companies expect to initiate two additional trials of ARV-471 in 2021.

Source: Pfizer