Merck announced the initial presentation of data on the investigational use of KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy, in PD-L1 positive, advanced urothelial cancer, otherwise known as bladder cancer. Results from the early findings indicated a confirmed overall 24 percent response rate using KEYTRUDA as monotherapy as measured by RECIST v1.1, central review (n= 7/29: 95% CI, 10.3-43.5) including a complete response rate of 10 percent (3/29).

During the analysis, response durations spanned from 16+ to 40+ weeks with six out of the seven responders continuing on therapy. In the continuing study, 64 percent (61/95) of patients who were screened had tumors that were positive for PD-L1 expression.

These data, from a portion of the ongoing Phase 1b KEYNOTE-012 study, were presented on September 29 by Dr. Elizabeth R. Plimack, Fox Chase Cancer Center, Philadelphia, at the European Society for Medical Oncology (ESMO) 2014 Congress in Madrid, Spain (ABSTRACT #LBA23, as part of a late-breaking oral session.

KEYTRUDA is suggested for use in the U.S. at a dose of 2 mg/kg every three weeks to help treat patients with unrespectable or metastatic melanoma and disease progression after ipilimumab and, if BRAF V600 mutation positive, a BRAF inhibitor.

Dr. Alise Reicin, vice president, oncology, Merck Research Laboratories, said in a statement, “Although at this stage the dataset is small, we are encouraged by the response rate, complete response rate, and the durability of the response in patients suffering from advanced bladder cancer.” She continued, “As communicated previously, based on these data Merck will initiate a Phase 3 study this year to better understand the potential of KEYTRUDA in advanced bladder cancer.”

According to the Urology Care Foundation, bladder cancer is the sixth most common cancer in the U.S. In 2014, an estimated 74,000 Americans will be diagnosed with the disease and over 15,000 will die from the cancer.