On July 31, Merck announced that the FDA approved Keytruda monotherapy for patients with recurrent locally advanced or metastatic esophageal squamous cell carcinoma who had previously received at least one line of systemic PD-L1 expression (CPS ≥ 10).
This approval is based primarily on data from two studies. One is a multicenter, randomized, open-label, positive-drug-controlled KEYNOTE-181 study (NCT02564263) involving 628 patients with locally advanced or metastatic esophageal squamous cell carcinoma who had previously undergone at least one line of systemic therapy, with Her2 Positive patients are required to receive Her2 targeted therapy. Patients with a history of non-infectious pneumonia or who are currently associated with pneumonia, autoimmune disease, or requiring immunosuppressive therapy are excluded.
Patients enrolled will be classified according to tumor histology or regional stratification, such as esophageal squamous cell carcinoma (ESCC), esophageal adenocarcinoma (EAC), gastroesophageal junction carcinoma (GEJ) subgroup, and Asian patients and patients outside Asia. . Patients were randomized to a 1:1 randomized group of Keytruda 200 mg once every 3 weeks or the investigator’s choice of chemotherapy regimen (paclitaxel, docetaxel, irinotecan) until disease progression or intolerable toxicity.
The OSV risk ratio was 0.77 (95% CI: 0.63, 0.96) in the ESCC group, 0.70 (95% CI: 0.52, 0.94) in the PD-L1 positive patients, and 0.89 (95% CI: 0.75 in all patients). 1.05). The median OS of the Keytruda-treated group was significantly improved compared with the chemotherapy group (10.3 vs 6.7 months), with a median PFS of 3.2 and 2.3 months, respectively, with an ORR of 22% (including CR 5%) and 7% (CR 1%). ), the median response duration was 9.3 and 7.7 months, respectively.
Another trial was a multicenter, non-randomized, open-label KEYNOTE-180 study (NCT02559687) enrolling 121 patients with locally advanced or metastatic esophageal cancer who had previously undergone two systemic treatments for disease progression. The patient exclusion criteria were similar to the KEYNOTE-181 study. The results showed that patients with positive PD-L1 expression (n=35) had an ORR of 20%, and in 7 patients with a response, the DoR ranged from 4.2 to 25.1 months, and 5 patients had a DoR of more than 6 months.
Jonathan Cheng, vice president of clinical development for Merck’s Oncology, said that treatment options for patients with advanced esophageal cancer are very limited, especially after their disease has progressed. Keytruda is the first PD-1 therapy for patients with recurrent locally advanced or metastatic esophageal squamous cell carcinoma who have been treated with PD-L1 positive, providing an important treatment option for US patients and clinicians.
As of now, Keytruda is the only PD-1/PD-L1 drug approved for the treatment of esophageal cancer. In the first half of 2019, Keytruda’s global sales were $4.903 billion, which has already led Opdivo significantly.