Some interesting mail has come in after last week's post on comparative clinical trials. Reader C.B. that I spoke about here some time ago, but should have raised again:

"It seems to me that something else is being left out: not all patients respond the same way to any particular drug. . . Suppose that drugs X and Y are equally efficacious when given to the appropriate patient, but the population more responsive to X is smaller than that benefiting from Y. A simple comparative trial would suggest that Y was more effective because it assumes a single type of patient. On the basis of the results, people who should get X would only be allowed Y. . ."

It's true, there are a number of cases like this, and this is one of the traditional arguments for multiple drugs in a given class. I've made it myself. Given the state of the art, it's nearly impossible to untangle these things. In almost all cases, we have no idea why some people respond better to a particular therapy; it's trial and error. Clinically, these things are bottomless pits, so I think that comparative trials are going to be most useful in areas where a large number of patients respond to both drugs under study.

But we're in the process of inventing ourselves out of this situation. That's why all that money is being poured into pharmacogenomics - and quite rightly, although the end result is that many drugs are going to have their potential market size whacked into a rather more compact shape. The great thing about pharmacogenomics is that we're finally going to know who should take our latest drug, and we'll be able to find them and sell it to them. The terrifying thing, from the marketing standpoint, is that we're simultaneously going to find another group of patients, a potentially larger group with the same disease, who will never take that drug at all. It's going to be a better world, but one in which some business models (cancer therapy!) are going to have to change.

And in a similar vein, reader R. D. writes:

"I have yet to see someone make a rational case for why me-toos are bad. At most, the argument seems to be that if pharma would just stop spending all its time coming up with me-toos, we could get around to curing cancer and parkinsons and stuff. I think that's bunk. You and I both know that any pharma that could come up with cures for things like cancer or parkinsons could start their own mint. The reason they haven't is because it's HARD, not because they prefer to make less money by painting their old pills purple and trying to convince everyone that they're new and improved."

Purple? What on earth can you be talking about? No, the argument he's talking about is one that (in this form) I don't have too much time for, either. The me-too drugs are there to keep the coffers full to pay for the research that doesn't work out, and to tide companies over the dry spells. I can see the objections to the areas where there are six and eight therapies all piled up on top of each other (for example, does the world really need Crestor?) But if Crestor makes money, some of that's going to pay for something new.

And the reason for that touches on another favorite whipping boy: marketing and promotion costs. Keep in mind the inverse relationships between advertising costs, novelty, and the chances of success. A new drug that does something no one's ever seen for a major disease previously thought untreatable - isn't that what makes everyone happy? How much, comparatively, would have to be spent to market such a therapy? There's no competition - it would sell itself! But what are the chances that any of us are going to find and develop such a wonder?

(OK, some of you are saying "Viagra! First on the market, first in the category, promotion out the wazoo!" But keep in mind: no one was sure that men would actually go to their doctor and admit their symptoms - thus the advertising blitz. And Prizer knew, with all the other companies working on PDE subtypes, that competition would be coming soon. They needed all the brand recognition that they could buy.)

Meanwhile, contrast a first-ever wonder drug with, say, the umpteenth statin. It's a crowded field, and you have to spend like crazy to make headway. The thing was a bit lower-risk to develop, since you knew that the rationale was there. But your cost-of-sales figures are going to be uglier, and nothing's ever going to help them.

My point is that a company needs both of these kinds of drugs. You can't hope to live only on the first kind, because they happen so seldom and so unpredictably. And no one's trying to live only on the second kind, either, because you've traded higher costs their for relative security. Everybody developing one of the first class wishes they had some of the second to tide them over. And everyone with drugs in the second class is looking for one from the first.