Thursday, November 19, 2009

Plavix Label Change: Good For Effient Now, Bad For Brands in the Long Run?

The Food & Drug Administration's public health alert on Plavix is, as we point out in "The Pink Sheet" DAILY, a nice boost for Eli Lilly and Daiichi Sankyo, who market the competing platelet agent Effient.

But the back story to this regulatory action merits closer attention by all pharmaceutical sponsors. This is no ordinary labeling change, and the implications of how the regulatory response came about only underscore how difficult it will be for all sponsors who hope to sustain (or revive?) the blockbuster model in the years to come.

This labeling change suggests a model for application of pharmacogenomic research that biopharma companies will find very threatening: it sure looks like sponsors hoping to build blockbuster franchises are at a huge disadvantage against payors hoping to limit those opportunities.

And that's why this labeling change may end up being bad news for all brands in the long run--very much including Effient.

First, the news: FDA has revised Plavix labeling to emphasise that the Bristol-Myers Squibb/Sanofi Aventis blockbuster doesn't work too well in patients who are poor metabolizers of the drug. In particular, FDA is concerned about impairment of the CYP2C19 metabolic pathway, whether because of genetic variations or coadministration of other drugs, including the widely used proton pump inhibitor omeprazole (Prilosec).

Okay, none of that is actually news. FDA first issued the warning in January, and quietly modified Plavix labeling in May.

What is news is that FDA has decided that information is now a formal warning, rather than a milder precaution--and, more importantly, the agency chose to amplify that warning (especially regarding PPI use) via a media conference call.

It is easy to see why Lilly and Daiichi would be pleased: anything that complicates the decision to prescribe Plavix will help them make the case that doctors should prescribe Effient (and, as we've already pointed out, they need all the help they can get).

Okay, so this sounds almost reassuringly like a classic story of head-to-head competition in a blockbuster class, and how the regulatory process can play to one side's advantage. Plavix is dinged, Effient benefits.

But this is nowhere near that simple.

Because there are third parties involved: payors and pharmacy benefit managers. The interaction between PPIs and Plavix was first publicized by Aetna and by Medco, both of whom used claims data to suggest an association between PPI use and diminished outcomes for patients treated with Plavix.

Its not just that payors capitalized on a safety issue: they really drove the regulatory response and the application of a newly discovered pharmacogenomic marker. In Medco's case at least, Chief Medical Officer Robert Epstein told us, the whole idea was to find a way to test the emerging theory that CYP2C19 genotyping may predict Plavix response. Since Medco didn't have genotyping data on patients in its database, it looked at concomitant use of omeprazole instead, since the PPI is a known inhibitor of the 2C19 pathway.

FDA's first public health alert followed the Aetna and Medco claims studies; the latest one came after Bristol and Sanofi conducted a drug interaction study confirming the observational results. That's certainly not a regulatory model sponsors are eager to consider--especially since we would be willing to bet that the observational research that triggered the warning cost Medco much less than the clinical trial the sponsors were forced to conduct to confirm it.

Medco, at least, isn't done. As we reported here, the company is now taking the next step, conducting a large scale observational study to test the hypothesis that the superior efficacy demonstrated by Lilly in its head-to-head study of Effient vs. Plavix can be explained by the inclusion of poor metabolizers of Plavix in the comparator group.

And Medco's interest most definitely is NOT in helping either brand in this class.

Medco's interests include advancing the company's positioning as a leader in therapy management, particular as it comes to applying pharmacogenetic knowledge. And Medco certainly wants to work with its payor clients to make sure insured members receive the best possible care.

But what Medco wants above all is to carve out a long term market for generic clopidogrel--and in effect limit Effient's share (as well as the share of all future brands in the class)--to whatever slice can't be held for the generic.

The study design, as Epstein explained to us, is simple: Medco will (at its own cost) run a genetic screen on patients prescribed Plavix to identify those who properly metabolize the drugs. It will then compare 14,000 of those patients to 14,000 Medco members who receive Effient, and see if there is a difference in cardiovascular outcomes.

Medco clearly expects to demonstrate that there is no meaningful difference between the two.

Now this whole thing could backfire on Medco. Its data could end up suggesting superior outcomes even when the comparison arm is enriched for Plavix response. (And Medco has registered the trial on, so while we doubt they would trumpet that result, they can't just bury it either.)

And the study could by itself end up promoting the launch of Effient. Certainly, Lilly and Daiichi are only too happy to have Medco's support in spreading the message that their drug is active regardless of that specific genomic marker.

Indeed, as part of the screening effort, Medco is likely to drive some conversions from Plavix to Effient: patients who are genotyped as poor metabolizers will be informed of that status (as will their physician). Medco will not make any recommendations, but it is safe to bet that many identified as poor responders to Plavix will switch therapies. Given that 30% or so of the population has the genotype in question, Medco is likely to notify about 6,000 people that they may not be getting the full benefit of their antiplatelet therapy with Plavix.

But that only underscores the bigger point. Medco is willing to make a relatively big investment--and even to help grow a potential blockbuster franchise in the short term--in order to help limit the size of that market in the long run.

And it will cost Medco far less to do that than it costs for sponsors to bring potential blockbusters to the market in the first place.

Now, Epstein wasn't willing to disclose how much this undertaking will cost, but he did suggest it isn't terribly expensive. Medco collects the outcomes data already, so the only cost will be running the genotyping program. Medco will be doing the tests in house, via its own CLIA-certified lab test, so that expense will be kept as low as possible.

All in all, that is not a trivial expense for a pharmacy benefit management company to take on spec, but we're willing to bet it is less than 1% what it cost for Lilly to "prove" the superiority of Effient in a head to head trial.

Which is why, when it comes to trying to establish blockbusters in an era of high payor influence and ever advancing knowledge of the heterogeneity of drug response, it seems like the odds are stacked in favor of those who want to keep market sizes small.

Look for much more on this topic in an upcoming issue of The RPM Report.

image from flickr user mafleen used under creative commons.

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