Boehringer’s Blood Thinner Dabigatran (Pradaxa) Unanimously Endorsed
Sep22

Boehringer’s Blood Thinner Dabigatran (Pradaxa) Unanimously Endorsed

After last week's Meridia and Lorqess drama, I could've really used some good news from an FDA panel. And on Monday, I got it- in the form of a unanimous endorsement for a new blood thinner. The drug getting the love is dabigatran etexilate, which was developed by family-owned Boehringer Ingelheim and will be marketed as Pradaxa if approved. It's one of a cadre of drugs trying to replace warfarin (also known as coumadin), a medication that has been on the market for over 50 years and is among the most difficult to manage. Warfarin prevents formation of blood clots and can reduce ongoing clots. Doctors prescribe it to prevent painful leg clots in patients getting hip or knee replacements, to prevent stroke in patients with an abnormal heart rhythm called atrial fibrillation, and more. We recently wrote about how warfarin is a dirt cheap and effective medication, but it interacts with a plethora of foods, herbal supplements, and other drugs. Pradaxa is already approved in several countries outside the U.S. for short-term use, preventing leg clots in patients getting hip or knee replacements. The drug blocks thrombin, a protease enzyme that sits near the end of the complex biochemical pathway known as the coagulation cascade. Just about all of the drugs being developed to replace warfarin, at least the ones toward the end of the pipeline, target either thrombin or Factor Xa, the protein immediately before thrombin in the pathway. FDA's cardiovascular and renal drugs advisory committee voted 9-0 in favor of approving Pradaxa for preventing stroke in patients with atrial fibrillation. (Boehringer-Ingelheim press release) This will be a longer-term stint on Pradaxa than post-hip or knee surgery patients typically experience. So the most important part of the panel's discussion, to me, was their assessment of the drug's effects on the liver. That's because in 2006, another thrombin blocker called ximelagatran, developed by AstraZeneca, was pulled from the market because of liver toxicity. When you dig into the briefing documents that FDA provided to the panel, you find this blurb on page 103: Based on these data, the risk of severe drug induced liver injury from dabigatran appears to be low. Because the perceived risk is low and frequent liver monitoring may not prevent serious cases from occurring (even if an association did exist), regular monitoring of liver tests is not recommended. So it seems that ximelagatran's liver issues may not be a class-wide problem. Still to be determined is what doses of the drug might be approved- read this post by Pharmalot for an assessment of why doses matter. FDA is expected to make its call on...

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Obesity Musings On Alkermes, J&J News
May25

Obesity Musings On Alkermes, J&J News

I am always on the lookout for news in the obesity drug area. But lately two of the molecular components of experimental obesity drugs in late-stage clinical trials-naltrexone and topiramate- are in the news for other reasons. Alkermes announced this morning that it will receive priority review from FDA for VIVITROL, an injectable extended-release formulation of naltrexone, for treating opioid-dependent patients, with a PDUFA date of October 12, 2010. The idea is that a once-monthly injection of VIVITROL would be given to lower cravings in people with a dependence on opioids such as heroin, Vicodin, or Oxycontin. VIVITROL is already approved for treating alcohol dependence. It's Alkermes's formulation that's new. Naltrexone as a chemical entity has been around for some time. DuPont originally marketed it as Trexan in 1984 but that form is now off-patent, as C&EN's Ann Thayer wrote back in 2006. I also promised that there was an obesity connection here, and indeed there is. Naltrexone is one of the two components in Orexigen's experimental obesity medication, Contrave, as I explained last year. Orexigen has developed its own proprietary sustained-release formulation of naltrexone and the experimental drug's other active ingredient-bupropion, an antidepressant and smoking-cessation aid that boosts dopamine signaling. Ortho-McNeil Pharmaceutical, a subsidiary of Johnson & Johnson, has agreed to pay $81 million (that's $6.1 million in criminal fines and $75.37 million from civil suits) for promoting its epilepsy medication Topamax for several uses not approved by FDA. This story has been in the news for nearly a month now (see Pharmalot's entry about it here) but the company pled guilty to the illegal marketing just last Friday, placing this item back at the top of my Google News list. One of the off-label indications J&J was promoting turns out to be obesity, according to the whistleblower who brought the case. Read the legal documents here [pdf format]. Thanks to Jim Edwards at BNET for posting these. Topiramate (the active ingredient in Topamax) is one of the two active ingredients in Vivus's experimental obesity drug Qnexa. But Vivus's formulation uses topiramate at a much lower dose than would be taken as a standalone...

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