Wedbush Securities anticipates more complete data of Oncothyreon Inc.'s (NASDAQ: ONTY) PX-866 in combination with docetaxel dosing at American Association for Cancer Research (AACR) Nov. 12.
Oncothyreon said it has initiated the Phase 2 portion of its ongoing Phase 1/2 trial of PX-866 in combination with the chemotherapeutic agent docetaxel (Taxotere) following successful completion of the Phase 1 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.
PX-866 is a pan inhibitor of the PI-3K/PTEN/AKT pathway, a critical cell signaling pathway that is activated in many types of human cancer. Aberrant activation and regulation of PI-3K is implicated in a large proportion of human cancers, where it leads to increased proliferation and inhibition of apoptosis (programmed cell death).
Oncothyreon said that in their 43 patient Phase 1 study, the recommended dose of PX-866 in combinations with docetaxel was the same as the single agent maximum tolerated dose suggesting an encouraging combination safety profile.
In the phase 1 trial, 43 patients with solid tumors were treated at 3 different dose levels of PX-866 in combination with 75 mg/m2 docetaxel, the standard when used as a single agent.
PX-866 was dosed orally on days 8-21 of cycle one and days 1-21 in subsequent cycles, in combination of 4 docetaxel dosed daily days 1-21 in each cycle until progression or unacceptable toxicity.
The combination was apparently well tolerated and was associated with an encouraging disease control rate (undisclosed) at higher dose levels; we anticipate more complete data at AACR Nov. 12-16, said Gregory Wade, an analyst at Wedbush Securities.
Recall that in previous studies PX-866 showed better results in the continuous dosing arm with 8/19 patients experiencing stable disease as the best response, 3 of whom continue on the treatment, while 7/45 patients on the interment dosing arm experienced SD.
Wade anticipates data from the several Phase 2 trials of PX-866 in multiple settings will be presented at American Society of Clinical Oncology (ASCO), Chicago, IL during June 1-5, 2012.
Given these results, Oncothyreon has initiated an open-label, randomized, Phase 2 study that will enroll up to 170 patients to evaluate PX-866 plus docetaxel versus docetaxel alone.
The two arm study will enroll 88 patients in Group 1 (44 per arm) with NSCLC receiving 2nd or 3rd line treatment. Group 2 (41 per arm) will enroll patients with locally advanced or squamous cell carcinoma of the head and neck after failure of prior therapy. The primary end point is PFS and secondary endpoints include ORR and OS.
Wade recalled that Oncothyreon is also investigating PX-866, their novel oral, irreversible pan-PI3 kinase inhibitor, in combination with cetuximab. The open-label, randomized, Phase 2 study will enroll up to 144 patients, to evaluate PX-866 plus cetuximab versus cetuximab alone in cetuximab naïve patients.
Patients will be assigned to one of two groups in a 1:1 ratio. Group 1 will include patients with metastatic CRC who have progressed or experienced recurrence following treatment with irinotecan (or intolerance to) and oxaliplatin. Group 2 will enroll patients with incurable progressive, recurrent or metastatic SCCHN.
The primary endpoint is objective response (OR), the secondary endpoints will include progression free and overall survival and duration of response and disease control rate. Data from the study is also anticipated at AACR Nov. 12-16, 2011.
In addition to the interim look at the STIMUVAX data potentially in Late 2011/Early 2012, the next major events for Oncothyreon include potential top-line Phase 2 PX-866 data from ongoing studies in the second half of 2011.
The brokerage reiterated its outperform rating on shares of Oncothyreon with a price target of $15.
Oncothyreon stock is trading up 1.12 percent at $6.34 on the NASDAQ Stock Market at 9:51 am EDT.