I've described in a prior post and many of my comments here how tarceva and iressa, oral targeted therapies against EGFR, have been pretty consistently impressive in never-smokers. Not infallibly great, but these agents have shown high response rates in the 25-50% range for never-smokers, and have also been pretty favorable for remote and minimal smokers. These groups have a high incidence of their tumor having an EGFR activating mutation. In the randomized trial that compared tarceva to placebo and showed a significant survival benefit, known as the NCI-Canada BR.21 study, tarceva more than doubled the survival of never-smokers compared with placebo. Among current or former smokers, the trend for tarceva was in the right direction, but it was much less dramatic, with an approximately 13% improvement in survival over the time course of the study. So far I've talked a lot about the favorable results for EGFR inhibitors in lifelong nonsmokers or minimal prior smokers, but the flipside of this is to focus on the less impressive results among smokers, who comprise more than 80% of the lung cancer population. One new trial is attempting to take advantage of that potential weakness and test a new standard chemotherapy against tarceva in smokers in hopes of proving that the standard chemo is superior (link here).

I'll cover the details and available history on the new drug, pralatrexate, in my next post. What's really interesting, adding a personal dimension to the story, is that this drug is being developed by Allos Therapeutics, where the Chief Medical Officer is Dr. Pablo Cagnoni. That doesn't mean anything to you yet, but the interesting part is that Dr. Cagnoni's prior job was as Vice President of Medical Affairs and Translational Research at OSI Pharmaceuticals, which developed tarceva and the BR.21 trial. So clearly he has an intimate knowledge of tarceva and some ideas about its strengths and weaknesses. And after leaving the old job, he and the folks at Allos are taking aim at a potential Achilles' heel for tarceva, figuring that beating it in the large population of current or ex-smokers may be easy pickings.

The trial will be a randomized phase IIb, which to me means that it will be basically like a phase III trial but with too few people to really be done exactly the way you'd do it with enough money. Enrolling second line advanced NSCLC patients who have previously received platinum-based chemo, the trial will accrue 160 patients from 50 sites internationally. This is too small to expect the FDA would approve it, but it could certainly boost interest in the new drug pralatrexate if the preliminary trial is positive. The trial is being run by Dr. Karen Kelly, who heads the oncology program at the University of Kansas and is a world leader in lung cancer, and also a very nice friend who gave us a sweet baby gift of a cool shirt that says "The Future of Rock & Roll":

(But I digress).

I must say that I think this is a smart and promising strategy for trying to get a new chemo drug approved for lung cancer. Most oncologists perceive that chemo is a little bit more active than EGFR inhibitors like Tarceva or Iressa, or they're at least more comfortable giving it, with the decades of experience with conventional chemotherapy. But some recent trials suggest that iressa performed comparably to single agent taxotere (prior post here) or navelbine (prior post here) in head to head comparisons. Interestingly, those trials didn't indicate that there are subsets that do much better with chemo or EGFR inhibitor, which countered our expectations (mine, at least). So it remains to be seen whether tarceva will be more or less comparable to pralatrexate, or a currently available standard chemo, in a smoking population. For now, I think this is a very interesting and new approach to drug development, with the added intrigue of a the backstory that Dr. Cagnoni left OSI and is now thinking about the potential weaknesses of a drug that he helped develop several years ago.

Of course, what is most important is that this line of research could very possibly lead to a new drug for lung cancer. I'll describe what we know about pralatrexate next.