Enrollment was stopped in a phase 2 study of
ridaforolimus, an investigational mammalian target of rapamycin inhibitor,
after patients with metastatic or recurrent endometrial cancer demonstrated a
nearly doubled PFS rate, according to interim results from a company release.
The interim analysis showed a significant improvement in
the primary endpoint, PFS, with a 1.7-month difference in median PFS
(P=.007). PFS in patients treated with ridaforolimus was 3.6 months in
comparison to patients treated with standard-of-care treatment (1.9 months).
The data were presented at the 13th Biennial Meeting of
the International Gynecologic Cancer Society held in Prague, Czech Republic.
Merck, under an exclusive license and collaboration agreement with Ariad
Pharmaceuticals, is developing ridaforolimus in multiple cancer indications.
“We are very encouraged by the data with oral
ridaforolimus, which for the first time demonstrated improvement in PFS in
patients with advanced
endometrial cancer receiving a targeted therapy in a
well-controlled clinical trial,” Amit Oza, MD, professor of
medicine at the Princess Margaret Hospital, in Toronto, Ontario, Canada, said
in the press release.
“These results support a previous non-randomized
study of ridaforolimus in the same
patient population,” Oza added.
The interim analysis was based on patients enrolled at
39 sites in North America and Europe randomly assigned to oral ridaforolimus
(n=57), oral progestin (n=48) or chemotherapy (n=9).
The most common adverse events observed with
ridaforolimus were mucositis (38.2%), hyperglycemia (27.3%) and stomatitis
(21.8%). Patients assigned to ridaforolimus had significantly more serious
adverse events (23.6%) than patients treated with the standard treatment
This was an interesting study result, considering the limited treatment
options available in metastatic endometrial cancer. The data certainly justify
further investigative efforts with this agent. However, the study was quite
limited in size, the actual evidence of improved outcome was really very modest
(median improvement in progression-free survival less than 2 months), and the
drug did have a number of concerning and clinically relevant side effects
– Maurie Markman, MD
Section Editor, Gynecologic Cancers