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."