Can Tumor Mutational Burden Guide Treatment in Metastatic Breast Cancer?

A study presented at the San Antonio Breast Cancer Symposium examined whether tumor mutational burden (TMB) was associated with outcomes in hormone receptor-positive, HER2-negative metastatic breast cancer patients treated with either pembrolizumab (Keytruda) or chemotherapy.

Findings showed that patients with high TMB had numerically more favorable survival when treated with the immune checkpoint inhibitor.

In this video, investigator Mariya Rozenblit, MD, of Yale School of Medicine in New Haven, Connecticut, discusses the importance of pembrolizumab as a less-toxic alternative to chemotherapy for patients with high TMB — and the need for consistent testing to identify patients who may benefit.

The following is a transcript of her remarks:

The exciting findings that we’re presenting in the poster is that when we looked at the data, the patients who were getting pembrolizumab were doing a little bit better, if not the same, as the patients who were getting chemotherapy. And so this is very exciting.

So this was in the population that had the tumor mutation burden above 10. The ones below 10, we didn’t see a benefit, which is expected. But I think it’s really important to remind people that this is a treatment option that’s out there that’s less toxic, that’s going to be easier for patients to tolerate than chemotherapy, and is probably a good option third or later lines for these patients.

And so it’s a reminder to kind of get that repeat testing, look for the tumor mutation burden, which we sometimes even forget to test for in the hormone-positive patient population.