Bulls, Bears Gird for Fight Over Peregrine's Controversial Lung Cancer Drug

The phase II study enrolled 121 patients with non-small cell lung cancer that no longer responded following chemotherapy treatment. These second-line lung cancer patients were randomized to receive bavituximab (at two doses) plus docetaxel or docetaxel plus a placebo. The study was conducted at 24 centers in the U.S and 29 centers in Russia, Ukraine, the Republic of Georgia and India.

Peregrine reported initial results from the study last May. The overall response rate for the 1 mg bavituximab arm was 15% and 17.9% for the 3 mg bavituximab arm, approximately double the control arm response rate of 7.9%. Response rate was the study's primary endpoint but Peregrine has not said whether the benefit favoring bavituximab reached statistical significance.

Median progression-free survival (PFS) in the bavituximab arms were 4.2 months and 4.5 months, respectively, compared to 3 months for the control arm. Again, Peregrine has not said whether the PFS benefit reached statistical significance.

Randomized, controlled studies produce the strongest, most objective data, which is why Peregrine and its investors are so excited and confident in the bavituximab results. Furthermore, Peregrine says an independent review board conducted the analysis of the trial, which further eliminates the potential for bias.

"This rigorous phase II trial demonstrates that not only is bavituximab well tolerated when given with docetaxel but it improves response rates, progression-free survival and overall survival of second-line chemotherapy in patients with advanced non-small cell lung cancer," said oncologist Dr. David Gerber of University of Texas Southwest Medical Center and the lead investigator of the study, in a statement. "If a phase III trial confirms these findings, bavituximab could become a major component of standard treatment for patients with this challenging disease."

Not so fast, say Peregrine bears, immediately seizing on the lack of statistical significance across any of the study's endpoints to raise doubts about bavituximab's benefit. More than half of the patients enrolled in the study were recruited from Eastern Europe and India -- geographies with a reputation for producing overly positive results that cannot be reproduced in later, larger confirmatory trials.

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