A new experimental breast cancer drug from Arvinas and Pfizer has modestly slowed disease progression in patients with tumors that have changes to a specific gene, but its use will likely remain narrow if it wins approval.
The study results, set to be presented at the American Society of Clinical Oncology’s annual meeting, provide more clarity on the drug’s potential benefits and limitations. The drug, vepdegestrant, is an oral pill that works differently from existing treatments by breaking down estrogen receptors and cutting off signals that promote tumor growth.
In a Phase 3 trial, vepdegestrant was tested against the injectable drug fulvestrant in 624 people with advanced breast cancer. While the findings suggest that vepdegestrant may be a new option for patients with specific mutations, its use will likely remain limited to those with ESR1 gene changes.
The study showed that vepdegestrant extended progression-free survival by five months for patients with ESR1 mutations, compared to two months for those on fulvestrant. However, among all participants, median progression-free survival was similar: 3.8 months on vepdegestrant versus 3.6 months on fulvestrant.
Pfizer and Arvinas plan to submit an approval application for vepdegestrant to the FDA in the second half of this year, but have scaled back their development plans for two other Phase 3 trials. The companies also removed one-third of its staff in May.
The study’s results highlight the need for combination therapies and continued development in this space. Researchers believe that treating ESR1-mutated breast cancer remains challenging, and vepdegestrant could be a valuable option for patients with this specific mutation.
Source: https://www.biopharmadive.com/news/arvinas-pfizer-veritac-asco-full-results-breast-cancer/749488