quarta-feira, dezembro 15, 2004

Sobre ddI genérico e Zerit ER

Martin Delaney do Project Inform sobre o aparecimento do ddI (Videx) genérico e o fim do Zerit Extended Release (ER).

It now looks like there won’t be an extended release version of Zerit after all. Bristol’s in-house people were unable to come up with a successful large scale process for the extended release version.

They next brought in the outside consultants, but they too have so far failed to solve the production problem. At this stage, the only possible solution left is to simply start all over again, which apparently doesn’t make economic sense to the company. There would still be no guaranty that they could succeed. So, sometime soon, we can expect an announcement about this.

It sounds like BMS jumped the gun on extended release Zerit, announcing a product before they knew whether it could be produced in large quantities. I know some will suspect this was somehow deliberate, but that doesn’t make any sense. BMS has spent a very large chunk of change trying to come up with this product and running trials to please the FDA. How would it possibly be in their interests to now dump the product? If anything, given the sudden appearance of the generic ddI, it would seem they need all the nuke business they can get.

The official licensure date when ddI was legal transferred by the NIH to Bristol was in 1991 (yes, I know studies started earlier). This gave them patent coverage that would technically extend to 2007 (16 years), but there are other factors involved.

One was the exclusivity of “data” – this period lasts for 30 months, but it restarts each time a new version of a product hits the market. “Data exclusivity” prevents other companies from using the patent holder’s data to support other applications to the FDA, such as from generic companies. The last “new” version of ddI was sometime in 2001. Thus, Bristol’s hold on their data expired some time this year. That means that the generic company, Barr, could now use Bristol’s data for their own use, which they did.

Barr submitted an application to the FDA to sell a generic version of ddI. They submitted it under the new rules created for the PEPFAR program, which was something of a surprise to everyone. The PEPFAR process was designed to allow quick approval of generic drugs for use in developing nations, but perhaps there’s nothing stopping people from making such applications that way for US use. This point is unclear to me. All I know is that Barr submitted an application under the PEPFAR rules and the FDA accepted and processed it. Since Bristol’s patent formally extends to 2007, they could challenge Barr in court, and they’d probably win. But they would clearly not win in the court of public opinion. Thus, it is Bristol’s decision not to fight over it. I don’t think ddI is that important to them in their overall HIV portfolio, and the climate is one in which they probably don’t want to seem to be blocking the way for lower prices.

So, as far as I can tell, that’s what’s happened. The most interesting aspect of it is that FDA accepted a filing under the PEPFAR rules, which don’t require very much on the part of the generic manufacturer.

Some have wondered how much of a difference this will make on the cost of treating people with HIV. Overall, not very much. ddI is not that widely used and today is mostly picked up only in relative salvage settings. Also, the recent concerns about negative interactions between ddI and tenofovir haven’t helped the ddI market. So it seems like Bristol doesn’t feel it has a great deal to gain here by fighting, and perhaps a lot of lose in terms of public opinion.

Whether this approach will lead to other generic applications under the PEPFAR rules is uncertain, but it’s hard to see why it wouldn’t. But I don’t think we should assume that the sponsors of all the other HIV drugs are going to be so quick to let their remaining years of patent protection slip away. You can bet they won’t. But it might present a real public relations challenge for them.

As for pricing, the only figure I’ve heard is that the Barr generic ddI will cost about 19% less than Bristol ddI, at the wholesale level. This isn’t very much, and there are already discounts of this size or larger being given on ddI for ADAP, Medicaid, and the VA. We don’t know what kind of discounts will be offered to these government payers by Barr. This lack of big difference underlines a point about one of the differences between the US and much of the rest of world when it comes to generics. In most countries, generics cost quite a bit less than brand name drugs. For some reason, in the US the price difference is considerably smaller, and thus generics offer less of an advantage. No idea why...

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