Tuesday, July 12, 2005

Ethnopharmacology I

A hypothetical spot on BET:

Voiceover: [smooth African-American female voice, straight from Lite Jazz 10X] Heart failure is a major problem and a leading cause of death among African-Americans. In fact, heart failure disproportionately affects African-Americans.

Dr.DeFACCto: No argument here.

V/O: Now there's a new treatment for heart failure made especially for African-Americans, that's clinically proven to decrease complications and death from heart failure.

Dr. D: Weeelll, I don't know about new. After all, VHEFT-I was published in what, 1986? Aside from that, though, does the drug really know your nationality, too?

V/O: All-new BiDil® is now approved for treatment of heart failure in African-Americans. BiDil® is not for everyone; possible side effects include, but are not limited to: rash, headache, constipation, diarrhea, depression, mania, hair loss, excessive hair growth, painful genital ulcers, lupus, dizziness, headache, insomnia, hypersomnia, polysomnia, and others too horrible to mention...*

Dr. D: Yadda yadda ya.

V/O: So if you or a loved one, who happens to be African-American, has heart failure, ask your doctor about BiDil®. Specifically, ask Dr. DeFACCto. Do it today.

Dr.D: Huhh? Whazza?
[stirs self, wipes cigar ash from tweed shooting jacket] Must've been in a revery there. Well, certainly, the release of this 'new' drug raises a host of questions. Let's see if I can tackle a few of them here.

A-HeFT survival curve
  • Is this really a new drug?
    It's a new, fixed-dose combination drug, but the two component drugs, hydralazine and isosorbide dinitrate, have been around for decades.

  • Does it work?
    Actually, the data from the A-HeFT trial, which is the basis for its approval, are impressive (click graph for humanly readable version). This benefit in survival is in addition to standard heart failure therapy, although one could quibble as to how aggressively 'standard heart failure therapy' was pursued in the two groups.

  • How does the drug know if you're African, or American?
    Clearly, people of African descent have different frequency distributions than Europeans for many genes besides those involved in expression of obvious external traits. The authors of the trial posit that there are ethnic differences in the body's physiological reponses to weakening of the heart muscle. This is based on 'hindsight' review of previous studies which seemed to show black patients responding to this therapy and not whites. In all people, these response mechanisms tend to be beneficial in the short term, but maladaptive over the long term, contributing to the progression of heart failure and ultimately death. And as for nationality, the drug is indicated for use in "self-identified black patients" without regard to nationality.

  • Will it work in white folks, too?
    Aye, there's the rub. Nobody knows. And if Nitro-Med (the manufacturer) has any say about it , we'll likely never find out. Their patent is based on this drug's usefulness in black populations only, and it's an open question (to me, anyway) as to whether the patent would hold up if the drug were proven to be beneficial in a more general population. But it's all moot, anyway. These two medications are already available generically, for about $24 a month retail, when BiDil will sell for $180 a month, wholesale. But this is based on a fiction, as they say they'll sell to patients without pharmacy coverage for $25 a month.

  • Economic shenanigans aside, is this a good thing or bad?
    As an applied scientist, I'm always looking for the mechanism. Give me a blood test I can check which will predict whether Mrs. Jones is going to respond to this drug, irrespective of her skin color, and I'm reasonably happy. In a way, the advent of this drug is a step in that direction, toward individually tailored therapy, so I'm saying it's a good thing, mostly.

  • Why the Roman numeral "I" in the title?
    Hey, you never know when inspiration will strike again. [settles back down to deep contemplation]
*
BTW, the lupus thing is real , but real uncommon. The others I made up. Except headache; nitrates make your head feel like it's gonna blow.

2 Comments:

At 2:01 AM, Anonymous Anonymous said...

Always enjoy reading what Dr. DeFACCto has to say. But what happened to Dr. Diastole? Is he on sabbatical?
Mistress Pneumoniker

 
At 9:28 PM, Blogger Dr. DeFACCto said...

Thanks, MP. Dr. Diastole went on, uh, a trip. Yeah, that's right. A fishin' trip. To the ocean. Wore his new shoes and everything. And I don't mean shoes in the abstract, if you get my drift.

 

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