Eisai Co., Ltd. and Merck (MRK), known as MSD outside the United States and Canada, announced that they received Breakthrough Therapy Designation from the U.S. Food and Drug Administration (FDA) for Eisai's multiple receptor tyrosine kinase inhibitor LENVIMA® (lenvatinib) in combination with Merck's anti-PD-1 therapy KEYTRUDA® (pembrolizumab) for the potential treatment of patients with advanced and/or metastatic renal cell carcinoma (RCC). The LENVIMA and KEYTRUDA combination therapy is being jointly developed by Eisai and Merck. This is the second Breakthrough Therapy Designation for LENVIMA and the twelfth Breakthrough Therapy Designation granted to KEYTRUDA.

The Breakthrough Therapy Designation is an FDA program intended to expedite development and review of drugs for serious or life-threatening conditions. In order to qualify for this designation, preliminary clinical evidence must demonstrate that the drug may provide substantial improvement over currently available therapy on at least one clinically significant endpoint. The benefits of this Breakthrough Therapy Designation include more intensive guidance on an efficient drug development program, access to a regulatory liaison to help accelerate review time and eligibility for rolling review as well as priority review.

This Breakthrough Therapy Designation was based on the results of the RCC cohort in Study 111, a multicenter, open-label phase 1b/2 clinical study being carried out in the U.S. and the European Union (EU) to evaluate the efficacy and safety of LENVIMA in combination with KEYTRUDA in subjects with selected solid tumors.

Dr. Takashi Owa, Vice President, Chief Medicine Creation Officer, Oncology Business Group, Eisai, commented: "We are encouraged that the FDA has recognized the potential of LENVIMA plus KEYTRUDA for patients with advanced and/or metastatic renal cell carcinoma with the Breakthrough Therapy Designation. As a human health care company dedicated to giving our first thought to patients, we are committed to working closely with Merck and the FDA to expedite this clinical program with the hope that we may offer another important option for patients in need."

"The FDA's Breakthrough Therapy Designation for the LENVIMA and KEYTRUDA combination in advanced and/or metastatic renal cell carcinoma provides us with the opportunity to accelerate our effort to bring an important potential treatment option to these patients," said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. "We remain committed to understanding the full potential of KEYTRUDA across cancers and treatment settings, and our collaboration with Eisai is one of the many ways we are executing on this commitment to helping more patients."

The combination of LENVIMA (lenvatinib) and KEYTRUDA (pembrolizumab) is investigational. The efficacy and safety of this combination has not been established.

About Study 111

Study 111 is a multicenter, open-label phase 1b/2 clinical study being carried out in the U.S. and EU to evaluate the efficacy and safety of LENVIMA in combination with KEYTRUDA. The primary objective of the phase 1b part was to determine the maximum tolerated dose. Patients with unresectable solid tumors (renal cell carcinoma, endometrial cancer, non-small cell lung cancer, urothelial cancer, squamous cell head and neck cancer and melanoma) who had progressed after treatment with approved therapies or for which there are no standard effective therapies available were administered 24 mg of LENVIMA orally daily, as well as 200 mg of KEYTRUDA intravenously every three weeks. Dose reductions of LENVIMA were permitted based on observed toxicity. The phase 2 part was conducted with patients who had select solid tumors with 0-2 prior lines of systemic therapy (unless discussed with the sponsor), with a recommended dosage of 20 mg of LENVIMA daily and 200 mg of KEYTRUDA every three weeks as determined based on the results of the phase 1b part. The primary endpoint of the phase 2 part was objective response rate at 24 weeks after treatment began, with select secondary endpoints including objective response rate, disease control rate, progression-free survival and duration of response. Currently, the phase 2 part is underway, with enrollment expanded for the endometrial cancer cohort.