--FDA rejects Merck treatment for bone sarcoma
--Rejection comes after FDA panel had voted against the treatment
--Merck continuing talks on treatment with European regulators
(Adds more context, beginning in paragraph three.)
By Tess Stynes
Merck & Co. (MRK) said the U.S. Food and Drug Administration rejected its new drug application for an investigational maintenance treatment for patients with metastatic soft tissue, or bone sarcoma.
The pharmaceutical giant received a complete response letter from the FDA, which said further clinical trials of the treatment, ridaforolimus, would be needed to assess its effectiveness and safety before any potential approval.
In March, an FDA advisory panel had rejected the drug on concerns it didn't work well enough to offset potentially serious side effects.
"Merck remains confident in the potential of ridaforolimus," said Eric Rubin, vice president, clinical research oncology, at Merck. "We will continue to work closely with the FDA to define potential paths forward for this investigational therapy."
Merck said it also is in continuing talks with health regulators in Europe and other countries regarding ridaforolimus and is studying the treatment in "combination with other mechanisms in several tumor types."
Ridaforolimus, which Merck is proposing to sell under the brand name Taltorvic, was initially developed by Ariad Pharmaceuticals Inc. (ARIA). Merck bought the rights to finish development of Taltorvic, which targets a protein called mTOR that is involved in cancer growth.
A Merck study showed patients on ridaforolimus had a median progression-free survival--or the time before cancer starts growing again--of 17.7 weeks, compared with 14.6 weeks for patients on the placebo. An FDA analysis of that study, however, suggested the difference was about two weeks.
The agency said in March that the progression-free survival difference in Merck's study was "small" and questioned whether that difference was meaningful given the drug's side effects, which include infection, rash and, in some cases kidney damage.
Merck shares gained a nickel to $37.55 in recent after-hours trading. Ariad shares slid nine cents to $16.11.
--Jennifer Corbett Dooren contributed to this article.
-Write to Tess Stynes at email@example.com