FDA Approves VENTANA PD-L1 Assay as a Cemiplimab CDx in NSCLC

The VENTANA PD-L1 Assay can now be used to detect PD-L1 expression in patients with non–small cell lung cancer to determine eligibility for treatment with cemiplimab.

The FDA has expanded the label for the VENTANA PD-L1 (SP263) Assay. The test is now an approved companion diagnostic to identify patients with non-small cell lung cancer (NSCLC) who are eligible for treatment with the PD-1 inhibitor, cemiplimab (Libtayo).1

"Diagnostics, like our high medical value PD-L1 assay portfolio, enable personalized medicine to help improve patient outcomes," said Jill German, head of Pathology Lab, Roche Diagnostics, in a press release. "This approval helps physicians make more confident treatment decisions by identifying patients with tumors that may respond to the immunotherapy Libtayo."

The sensitivity of the VENTANA PD-L1 assay was evaluated in a head-to-head study against the PD-L1 IHC 22C3 pharmDx assay. To determine the superior test, investigators looked at 431 NSCLC samples that were analyzed with either the VENTANA PD-L1 Assay or PD-L1 IHC 22C3 pharmDx assay in routine clinical practice.2

Testing with both assays was performed on 314 portions of archived tissue of surgically resected NSCLC samples to assess PD-L1 expression. The investigators looked at each assay and its relationship to formalin-fixed paraffin-embedded (FFPE) block age and section storage condition.

Results from the study showed that the higher tumor proportion score shown with PD-L1 IHC 22C3 pharmDx assay compared with the VENTANA PD-L1 assay correlated with more recent block (P = 0.007 and P = 0.009, respectively). Overall, the PD-L1 IHC 22C3 pharmDx assay was less sensitive depending on the conditions of the laboratory whereas the VENTANA PD-L1 assay maintained its sensitivity.

As a companion diagnostic for cemiplimab, the VENTANA PD-L1 assay will be able to identify patients with NSCLC who have no EGFRALK, or ROS1 aberrations and can receive highly effective treatment. Cemiplimab in combination with chemotherapy was shown to significantly improve overall survival (OS), progression-free survival and objective response rate in this patient population. According to results from Study 16113 (NCT03409614), the median OS was 21.9 months (95% CI, 15.5 to not evaluable) in the cemiplimab plus chemotherapy arm compared with 13.0 months (95% CI, 11.9-16.1) in the placebo plus chemotherapy arm (HR, 0.71; 95% CI, 0.53-0.93], two-sided P = 0.0140).1,3

The median PFS was 8.2 months (95% CI: 6.4-9.3 months) in the cemiplimab plus chemotherapy arm vs 5.0 months (95% CI: 4.3-6.2 months) in the placebo plus chemotherapy arm (HR, 0.56; 95% CI, 0.44-0.70, P <0.0001).3

The confirmed ORR in the cemiplimab arm was 43% (95% CI: 38-49) compared with 23% (95% CI: 16-30) in the placebo arm.

In Study 16113, there were 466 patients in the cemiplimab plus chemotherapy arm who received treatment every 3 weeks for 4 cycles followed by cemiplimab and maintenance chemotherapy. Patients in the placebo arm were given placebo plus platinum-based chemotherapy every 3 weeks for 4 cycles, also followed by placebo and maintenance chemotherapy.

The most common adverse events (AEs) observed with these treatments were alopecia, musculoskeletal pain, nausea, fatigue, peripheral neuropathy, and decreased appetite. These AEs occurred in more than 15% of patients in the study.


1. Roche receives FDA approval of label expansion for VENTANA PD-L1 (SP263) Assay to identify patients with locally advanced and metastatic non-small cell lung cancer eligible for Libtayo. News release. Roche. March 6, 2023. Accessed March 6, 2023.

2. Kim SY, Kim T, Park CK, et al. Comprehensive comparison of 22C3 and SP263 PD-L1 expression in non-small-cell lung cancer using routine clinical and conditioned archives. Cancers (Basel). 2022;14(13): 3138. doi: 10.3390/cancers14133138

3. FDA approves cemiplimab-rwlc in combination with platinum-based chemotherapy for non-small cell lung cancer. News release. FDA.gov. November 8, 2022. Accessed March 6, 2023. https://bit.ly/3zZZie0

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