Merck receives complete response letter from U.S. FDA for investigational medicine ridaforolimusr

Merck (NYSE: MRK), known as MSD outside the United States and Canada, announced today that the U.S. Food and Drug Administration (FDA) has issued a complete response letter regarding the New Drug Application (NDA) for ridaforolimus. Ridaforolimus is an investigational oral mTOR inhibitor under development for maintenance therapy for patients with metastatic soft tissue or bone sarcoma who have stable disease or better after four or more cycles of chemotherapy.

The complete response letter states that FDA cannot approve the application in its present form, and that additional clinical trial(s) would need to be conducted to further assess safety and efficacy. Merck also is in ongoing discussions with health authorities in Europe and other countries as part of their application procedures for ridaforolimus for the treatment of metastatic soft-tissue or bone sarcomas in patients who had a favorable response to chemotherapy. Additionally, Merck is studying ridaforolimus in combination with other mechanisms in several tumor types.

“Merck remains confident in the potential of ridaforolimus,” said Eric Rubin, M.D., vice president, Clinical Research Oncology, Merck. “We will continue to work closely with the FDA to define potential paths forward for this investigational therapy.”

Sarcomas are a group of cancers of connective tissue of the body for which there are currently limited treatment options. Sarcomas can arise anywhere in the body and are divided into two main groups – bone tumors and soft-tissue sarcomas.

Ridaforolimus is an investigational small-molecule inhibitor of the protein mTOR, a protein that acts as a central regulator of protein synthesis, cell proliferation, cell cycle progression and cell survival, integrating signals from proteins, such as PI3K, AKT and PTEN, known to be important to malignancy.

As part of an exclusive license agreement with ARIAD Pharmaceuticals, Inc (Nasdaq: ARIA), Merck is responsible for the development and worldwide commercialization of ridaforolimus in oncology.