Introgen's Data-Mining Misleads

Steering this back to Introgen, nearly three years ago the company issued a press release detailing results from a combined analysis of three phase II studies of Advexin in 217 patients with head and neck cancer. Here's how the company described the trial (emphasis added):

"The objective overall response rate of Advexin monotherapy was 10 percent (complete and partial response with greater than 50 percent reduction in tumor size). Tumor growth control (stable disease or better) was achieved in 59 percent of all treated lesions. The primary objective of the trials was to assess tumor growth control and safety following Advexin monotherapy in patients with recurrent head and neck cancer. All patients had failed previous conventional treatment."

Introgen's phase II study had as its primary endpoint, or objective, tumor response to Advexin. That was the prospectively defined analysis. A 10% overall response rate is not much to write home about.

But more than two years later, Introgen says it discovered something new from this phase II database. The following is from a press release issued on June 5, 2006:

"Researchers at Introgen Therapeutics and their clinical collaborators have identified a set of prognostic indicators associated with high response rates and increased survival in Phase 2 trials of ADVEXIN in patients with recurrent squamous cell carcinoma of the head and neck (SCCHN)."

The release went on to say (the italics are mine): "A molecular biomarker predictive of ADVEXIN activity is abnormal p53 function detected in tumor tissues by a routine laboratory test. In patients with the abnormal p53 marker, ADVEXIN therapy was correlated with a statistically significant increase in median survival of 11 months compared to only 3 months for patients without abnormal p53." [p53 is a gene believed to regulate cell growth.]