An experimental breast cancer treatment co-developed by Pfizer and Arvinas significantly improved the time some patients lived without the disease worsening, but failed to achieve statistically significant results in others in a late-stage study.

Pharma giant Pfizer and Arvinas’s human epidermal growth factor receptor 2 (HER2) negative breast cancer therapy, vepdegestrant, has seen mixed results after it was only able to extend progression-free survival (PFS) in certain patients in a Phase III trial.