Dr Mayadev on Using PD-L1 TAP as a Predictive Biomarker for Locally Advanced Cervical Cancer

“We found that patients with [PD-L1] TAP [levels] greater than or equal to 20% had a significant benefit with the addition of durvalumab to chemoradiation.”

Jyoti Mayadev, MD, FASTRO, a professor of radiation medicine and applied sciences at the University of California (UC) San Diego, as well as a radiation oncologist at the UC San Diego Moores Cancer Center, highlighted the clinical significance of using tumor area positivity (TAP) for PD-L1 as a predictive biomarker for patients with locally advanced cervical cancer treated with chemoradiotherapy (CRT) with or without durvalumab (Imfinzi) in the phase 3 CALLA trial (NCT03830866).

Traditionally, biomarker work in cervical cancer has focused on PD-L1 expression and its role in modulating immune response, Mayadev began. She explained that TAP offers a more nuanced measure of PD-L1 tumor burden that may better stratify patients for benefit from immunotherapy. An exploratory analysis of CALLA demonstrated that patients with TAP levels of at least 20% (n = 186) experienced improved clinical outcomes with the addition of durvalumab to CRT, particularly in relation to molecular clearance of circulating tumor DNA (ctDNA). Careful, the strikethrough part doesn’t seem to be mentioned anywhere in the clip or in the interview overall, according to the QA

Mayadev emphasized that patients with TAP levels of at least 20% were more likely to achieve normalized ctDNA levels during treatment, which correlated with improved responses and favorable outcomes compared with patients whose TAP expression levels remained below 20%. She noted that this association between TAP expression, ctDNA clearance, and treatment efficacy highlights the biological plausibility of TAP as a marker for immunotherapy sensitivity. These findings suggest that TAP may be an important tool for identifying subgroups of patients with locally advanced cervical cancer who derive the greatest benefit from immune checkpoint inhibition when combined with CRT.

In cervical cancer research, the integration of biomarker-driven analyses has become an essential part of clinical trial design to evaluate efficacy signals and inform future strategies for treatment optimization, according to Mayadev. She underscored that TAP in combination with ctDNA monitoring could serve as a dual biomarker approach that refines patient selection and ensures that immunotherapy is targeted toward those most likely to respond.

Mayadev explained that by identifying patients with higher likelihood of immunotherapy benefit, oncologists can optimize therapeutic strategies, reduce unnecessary exposure to immune checkpoint inhibitors, and improve long-term outcomes in this population. Mayadev concluded that the ongoing evaluation of TAP and ctDNA in cervical cancer trials represents a critical step toward personalized, biomarker-directed integration of immunotherapy in locally advanced cervical cancer.