Oncothyreon it has initiated the phase II portion of its ongoing phase I/II trial of PX-866 in combination with the chemotherapeutic agent docetaxel (Taxotere) following successful completion of the phase I dose escalation portion of the study. PX-866 is a small molecule compound designed to inhibit the activity of phosphatidylinositol-3-kinase (PI-3K), a component of an important cell survival signaling pathway.
The primary objective of the phase I portion of the trial was to determine the maximum tolerated or recommended daily dose of PX-866 to be given in combination with the standard dose of docetaxel administered once every three weeks to patients with advanced cancers for which docetaxel is considered standard of care. The phase I portion enrolled a total of 43 patients treated at 3 different dose levels of PX-866 in combination with the standard dose of docetaxel. Preliminary results indicated that combination treatment was well tolerated and associated with an encouraging disease control rate. The recommended daily dose of PX-866 in combination with docetaxel was determined to be the same as the single agent daily maximum tolerated dose. Additional results from the phase I portion of the trial will be submitted for presentation at an upcoming scientific meeting.
The phase II portion of the trial is an open-label, randomized evaluation of the antitumor activity and safety of PX-866 administered at the recommended daily dose in combination with docetaxel, versus docetaxel alone, in two groups of patients. Group I will enroll patients with non-small lung cancer receiving second or third line treatment. Group II will enroll patients with locally advanced, recurrent or metastatic squamous cell carcinoma of the head and neck after failure of prior therapy. The two groups will be randomized and evaluated independently.
Up to 170 patients may be enrolled in the phase II portion of the study including 88 (44 per arm) in group I and 82 patients (41 per arm) in group II. The primary endpoint of the phase II portion is progression free survival. Secondary endpoints include objective response rate and overall survival.