Oncothyreon Inc. (Nasdaq: ONTY) today
announced the initiation of a Phase 1/2 trial of PX-866 in combination
with vemurafenib (Zelboraf®). PX-866 is Oncothyreon's investigational
small molecule compound designed to inhibit the activity of
phosphatidylinositol-3-kinase (PI-3K), a component of an important cell
survival signaling pathway. Vemurafenib is a kinase inhibitor
indicated for the treatment of unresectable or metastatic melanoma with
the BRAFV600E mutation.
The Phase 1 portion of this trial will evaluate the safety and
tolerability of PX-866 in combination with twice daily oral
administration of vemurafenib in up to 36 patients with any BRAF-mutant
cancer. The trial will use a dose-escalation design to evaluate up to
three dose levels of PX-866 with up to two dose levels of vemurafenib
to determine the maximally tolerated or recommended dose of both PX-866
and vemurafenib to be used in Phase 2. The Phase 2 portion of the
trial will compare the anti-tumor activity and safety of PX-866 and
vemurafenib at the doses recommended from Phase 1 with vemurafenib
alone administered at the approved dose. This randomized Phase 2 trial
is expected to enroll 110 patients with advanced BRAF-mutant melanoma
and has a primary endpoint of progression-free survival.