Could TILs Serve as a Marker of Immunotherapy Benefit in Early TNBC?

At the American Society of Clinical Oncology (ASCO) meeting, long-term follow-up from the KEYNOTE-522 trial reinforced the survival benefit of pembrolizumab (Keytruda)-based therapy in early-stage triple-negative breast cancer (TNBC), but questions remain about how broadly immunotherapy should be used and whether biomarkers can help identify the patients most likely to benefit.

In this MedPage Today “Future Focus” video, Paolo Tarantino, MD, PhD, of Dana-Farber Cancer Institute in Boston, discusses the potential role of tumor-infiltrating lymphocytes (TILs) in guiding immunotherapy use and the challenge of balancing benefit with toxicity in early triple-negative breast cancer.

Following is a transcript of his remarks:

Reassuring and striking is not [something] that we see every day, such a remarkable survival benefit. Now, it comes with a cost and we all see it in real-world practice. The KEYNOTE-522 regimen is not easy and it’s a lot, but it really saves lives. And so I think it’s worth considering it for any patient with stage II and III triple-negative disease.

That said, there was a loud absence in the presentation and I do hope that at some point we’ll get to see the TILs subanalysis because there’s been some data, for instance, from the A-BRAVE trial of avelumab [Bavencio], suggesting that TILs may help identify patients that benefit from immunotherapy. It’s a hypothesis right now. So, for our audience, don’t use TILs to decide if to give immunotherapy, but I think we need the data and I do believe at some point it will be presented.

And I do hope the benefit of pembro is seen in all patients, but if actually we are able to select better patients, I would love to spare immune-related toxicity from patients that do not benefit from immunotherapy.

I do think there is something in between that we can do and we are starting to do, to give more neoadjuvant chemotherapy to stage I, especially T1c. So, knowing that you can understand better the prognosis for these patients, adapt adjuvant therapy with capecitabine and maybe in the near future with TROP-2 ADCs [antibody-drug conjugates], I think, will help. But I would not use immunotherapy in stage I. We are not there yet.