SAN FRANCISCO – A combination of a targeted therapy and an immune checkpoint inhibitor showed promising activity against advanced urothelial cancer in early data from a phase 1b/2 study.
In a cohort of 20 patients with urothelial carcinoma who were enrolled in a larger clinical trial testing the combination of the tyrosine kinase inhibitor (TKI) lenvatinib () and the checkpoint inhibitor pembrolizumab ( ) against urinary tract and other solid malignancies, 5 had an objective response to the combination, including one complete and four partial responses, for an objective response rate of 25%, reported , from Comprehensive Cancers Centers of Nevada in Las Vegas.
“This response rate warrants further investigation. The lenvatinib plus pembrolizumab combination will be studied in a phase 3 trial in urothelial carcinoma,” he said at the American Society of Clinical Oncology (ASCO) - Society for Immunotherapy of Cancer (SITC): Clinical Immuno-Oncology Symposium.
Dr. Vogelzang noted that urothelial carcinomas account for more than 90% of all bladder cancers. Pembrolizumab monotherapy is approved for treatment of patients with urothelial carcinoma who are ineligible for cisplatin and whose tumors have a combined positive score (CPS) for programmed death-ligand 1 (PD-L1) of 10 or greater or who are ineligible for platinum-based chemotherapy regimens and, in the second line, for advanced or metastatic urothelial carcinoma.
Lenvatinib, a multikinase inhibitor, is approved as monotherapy for radioiodine-refractory differentiated thyroid cancer, unresectable hepatocellular carcinoma, and in combination with everolimus for advanced renal cell carcinoma (RCC) after one year of antiangiogenic therapy.
Dr. Vogelzang reported results of the urothelial cancer cohort from a multicohort study testing the combination.
Twenty patients with histologically confirmed metastatic urothelial cancer were enrolled. The patients all had no more than two prior systemic regimens, good performance status, and a life expectancy of at least 12 weeks. The patients received oral lenvatinib 20 mg daily and pembrolizumab 200 mg intravenously every 21 days. The median patient age was 72 years. The cohort included 14 men and six women.
The objective response rate (ORR) at 24 weeks, the primary endpoint, was 25%, comprising one complete and four partial responses. Nine patients had stable disease, two had disease progression, and four were not evaluable for efficacy. The results were identical according to immune-related Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and modified RECIST version 1.1. Of the 16 evaluable patients, 12 experienced tumor-size reductions from baseline.
“Although there were five objective responses, there were an additional seven patients or more who had minor regressions of disease – clearly an active regimen,” Dr. Vogelzang said. Four of the patients, including one with a PD-L1–positive tumor and three with PD-L1–negative tumors were still alive, with the longest survival past 80 weeks since the start of therapy. The majority of patients, however, had no objective response or disease progression within about 20 weeks.
After a median follow-up of 11.7 months, the median progression-free survival (PFS) was 5.4 months, and the 12-month PFS rate was 26%.
In all, 18 of the 20 patients (90%) experienced a treatment-related adverse event of any grade, 10 had grade 3 or 4 events, and 6 had serious adverse events including one death from gastrointestinal hemorrhage that Dr. Vogelzang said appeared to be related to lenvatinib. A total of four patients (20%) had a treatment-related event leading to withdrawal or discontinuation, seven had a dose reduction, and 12 had an interruption in therapy, primarily of lenvatinib. The most common toxicities were proteinuria, diarrhea, hypertension, fatigue, hypothyroidism, decreased appetite with nausea, pancreatitis with increased lipase, skin rash, vomiting, and dry mouth.
In addition to the planned phase 3 trial of the combination in urothelial carcinoma, lenvatinib/pembrolizumab is also being studied for the treatment of RCC.
The study was supported by Eisai and Merck Sharp & Dohme. Dr. Vogelzang disclosed financial relationships with Caris Life Sciences, Pfizer, Up to Date, AstraZeneca, MedImmune, and other companies. Five coauthors are employees of Merck or Esai.
SOURCE: Vogelzang NJ et al. ASCO-SITC, .