February 23, 2021 - The FDA has approved the PD-L1 IHC 22C3 pharmDx assay, developed by Agilent Technologies Inc, for expanded use in patients with non–small cell lung cancer.
The FDA has approved the PD-L1 IHC 22C3 pharmDx assay, developed by Agilent Technologies Inc, for expanded use in patients with non–small cell lung cancer (NSCLC).1
The assay can now be utilized to help identify patients who may be candidates for treatment with cemiplimab-rwlc (Libtayo), which was granted FDA approval on February 22, 2021, for use as a single agent in the first-line treatment of patients with advanced NSCLC who have a PD-L1 tumor proportion score of 50% or higher.
The regulatory decision was based on findings from an analysis of 710 patients with a PD-L1 expression of 50% or higher who were randomized to receive cemiplimab in the phase 3 EMPOWER-Lung 1 trial (NCT033088540). Here, the agent resulted in a 32% reduction in the risk of death compared with chemotherapy. Specifically, the median overall survival (OS) in the investigative arm was 22 months versus 14 months with chemotherapy (HR, 0.68; 95% CI, 0.53-0.87; P = .0022).2
Moreover, the median progression-free survival (PFS) with cemiplimab was 6.2 months per blinded independent central review compared with 5.6 months with chemotherapy (HR, 0.59; 95% CI, 0.49-0.72; P <.0001).
The survival benefit associated with cemiplimab was reported across all subgroups evaluated in the trial, with the exception of OS in female patients.
“Anti–PD-1 therapies, including [cemiplimab], continue to broaden the potential for the treatment of patients across different cancer types,” Sam Raha, president of Agilent’s Diagnostics and Genomics Group, stated in a press release. “With the FDA approval of PD-L1 IHC 22C3 pharmDx as a companion diagnostic for treatment with [cemiplimab] monotherapy in advanced NSCLC, Agilent further strengthens its ability to elevate pathologist confidence in reporting results to oncologists and bolsters our role as a global pioneer in developing companion diagnostics for targeted treatments.”
The multicenter, open-label, phase 3 trial evaluated cemiplimab monotherapy compared with investigator’s choice of platinum-doublet chemotherapy in the frontline treatment of patients with advanced NSCLC whose tumors had a PD-L1 expression of at least 50%. The PD-L1 IHC 22C3 pharmDx was used to examine PD-L1 status in those enrolled to the trial. PD-L1 expression was evaluated in formalin-fixed, paraffin-embedded tumor samples at a central laboratory.
To be eligible for inclusion, patients had to be aged 18 years or older, have histologically or cytologically confirmed stage IIIB or IIIC or stage IV squamous or nonsquamous NSCLC with a PD-L1 expression of at least 50%, and ECOG performance status of 0 or 1, adequate bone marrow and organ function, as well as at least 1 measurable lesion per RECIST v1.1 criteria.
Patients who were never smokers or who had active or untreated brain metastases were excluded. Moreover, if patients had tumors that harbored EGFR mutations, ALK translocations, or ROS1 fusions, they could not participate. Anyone with active, known, or suspected autoimmune disease that needed systemic treatment within the previous 2 years or who had uncontrolled hepatitis B or C infection or human immunodeficiency virus, did not participate.
The primary end points of the trial included OS and PFS, while secondary end points comprised objective response rate (ORR), duration of response, health-related quality of life, and safety with cemiplimab versus chemotherapy. The pharmacokinetics and immunogenicity of the agent is also under exploration.
A total of 3662 patients were screened for the trial and 720 patients met the eligibility criteria. Notably, 74% of patients who experienced disease progression on chemotherapy were given cemiplimab as a crossover treatment. Thirty-two percent of patients who had progressive disease on cemiplimab went on to receive extended treatment with the addition of chemotherapy.
A total of 563 patients comprised the population of patients who had a PD-L1 expression of 50% or higher. The median age of these patients was 63.5 years and just under half, or 46.5%, were aged 65 years or older. Moreover, 85.5% were male, 76.5% were from Europe, and 73% had an ECOG performance status of 1. Additionally, 65% of patients were past smokers, 57% had nonsquamous histology, and 12% had brain metastases.
In this population, the overall median duration of follow-up was 10.8 months for cemiplimab and 10.9 months for chemotherapy. Just under half, or 46%, of patients were still receiving cemiplimab and 16% of patients were still receiving chemotherapy at the time of data cutoff.
The intent-to-treat (ITT) population (n = 710) was comprised of the 563 patients with a PD-L1 of at least 50% and a total of 56 patients who definitively had a PD-L1 expression of less than 50%. The overall median duration of follow-up with cemiplimab and chemotherapy was 13.1 months each.
In the ITT population, cemiplimab also demonstrated an improvement in OS versus chemotherapy, at 22.1 months (95% CI, 17.7–not evaluable) and 14.3 months (95% CI, 11.7-19.2), respectively (HR, 0.68; 95% CI, 0.53-0.87; P = .0022). Cemiplimab was also found to improve PFS compared with chemotherapy, at a median of 6.2 months (95% CI, 4.5-8.3) versus 5.6 months (95% CI, 4.5-6.1), respectively (HR, 0.59; 95% CI, 0.49-0.72; P <.0001).
Twenty-eight percent of the 355 patients who received cemiplimab experienced grade 3/4 treatment-emergent adverse effects (TEAEs), and pneumonia (5%) was the most commonly reported effect, followed by anemia (3%), and hyponatremia (3%). Grade 3/4 TEAEs were observed in 39% of those who received chemotherapy; anemia was experienced by 16% of patients, neutropenia presented in 10%, and thrombocytopenia occurred in 8%.