sTILs Warrant Research as Response Biomarker in Metastatic Breast Cancer

At the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, Daniel G. Stover, MD, spoke with CancerNetwork® about findings from the phase 3 CALGB 40502 (Alliance) trial (NCT00785291). In particular, he discussed how immune activation measured by stromal tumor infiltrating lymphocytes (TILs) may correlate with responses to microtubule-targeting agents among patients with metastatic breast cancer.¹

Stover, associate professor of medicine and director of Translational Breast Cancer Research at The Ohio State University Comprehensive Cancer Center, stated that results from the AURORA study may also suggest a relationship between stromal TILs and patient outcomes in the metastatic setting, especially in those with triple-negative breast cancer (TNBC).² However, he emphasized that additional trials are necessary for validating this association in other settings.

Transcript:

We performed multivariable analyses with additional factors and stromal TILs continued [to] trend towards association with outcomes. But there are multiple factors that influence a patient's response to these targeted therapies. Stromal TILs as a marker of immune activation should be one biomarker that could be incorporated as we think about optimizing therapy for patients. The [benefit] of stromal TILs is that it's such an accessible biomarker easily enumerated off routine slides.

This study certainly warrants further validation among additional samples in the metastatic setting. As we saw from the AURORA study presented in the same session, there is evidence that stromal TILs may have an association with outcomes in the metastatic setting, particularly among [TNBCs]. But the next step, beyond validating this in additional settings or situations, is to design those trials that can impact therapy decisions based on the stromal TIL number.

References

1. Stover DG, Salgado R, Savenkov O, et al. Association of tumor infiltrating lymphocyte quantity with survival in patients (pts) with metastatic breast cancer (MBC) receiving microtubule-targeting agents: post hoc analysis CALGB 40502 (Alliance). J Clin Oncol. 2023;41(suppl 16):1010. doi:10.1200/JCO.2023.41.16_suppl.1010
2. Hilbers F, Venet D, Agostinetto E, et al. Characterization of the immune microenvironment in matched primary and metastatic breast cancer lesions from the AURORA study: BIG 14-01. J Clin Oncol. 2023;41(suppl 16):1009. doi:10.1200/JCO.2023.41.16_suppl.1009