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Behind the Byetta Crisis: Is This Drug Really All That and a Bag of (Fat-Free) Chips?

gila-monster-byetta.jpgThe current big headache for Eli Lilly and Amylin is their diabetes drug Byetta, which the FDA has linked to six cases of fatal pancreatitis.

The two companies, which jointly market the drug, held a conference call yesterday in which they hoped to calm nervous investors. (It had mixed results: Lilly's stock stayed relatively steady but Amylin's crashed from $27.24 on Tuesday to $20.53 at the closing bell Wednesday.)

The issue behind the controversy, however, is how this drug -- originally developed from the saliva of the Gila monster (pictured) -- became such a huge success in the first place. It currently sells about $197 million a quarter. That's amazing considering how limited the appeal of the drug seems to be on paper.

First, it was originally approved by the FDA as an adjunctive therapy, which means that it's an add-on drug for diabetics who are having difficulty controlling their diabetes with the usual treatments, such as metformin or insulin. Add-on drugs tend to be less lucrative than first-line drugs, for the obvious reason that they serve only a portion of the total available patient population.

Second, it's more expensive than the older therapies, costing up to $225 a month, about 10 times the price of generics.

Third, it has some pretty nasty side effects. Lilly's product web site warns:

The most common side effects with BYETTA include nausea, vomiting, diarrhea, dizziness, headache, feeling jittery, and acid stomach. Nausea is most common when first starting BYETTA, but decreases over time in most patients.
A quick check of the diabetes blogosphere shows that there are plenty of patients who don't like it. Type "Byetta" and "sucks" into Google and see for yourself.

Nausea, expense and add-on status are usually enough to confine a drug to also-ran status when it comes to sales, particularly if those qualities are couple with headlines involving fatalities. So how did Byetta avoid that fate?

Consider this article from The New York Times, published in 2006. The story hits all the bases but the overall impression it leaves is that Byetta is a diet drug. Here's a sample:

On blogs they rave over its uncanny ability to melt away pounds, although some are wary of its side effects, which can include nausea and strange welts.
"I went from despair to life -- no hope to lots of hope," said the Rev. John L. Dodson, a 73-year-old pastor in Felton, Calif. Mr. Dodson, 5 feet 6 inches tall, says he has lost almost 60 pounds since starting Byetta last June and now weighs 178, his lowest weight since college.
The drug seems so effective for weight loss that some nondiabetics have begun using Byetta as a diet drug - causing concern among doctors who say such use has not been medically tested and could be dangerous.
One of the docs singing Byetta's praises to the Times was Dr. Alan Garber:
"My patients have done strikingly well on the drug," said Dr. Alan J. Garber, a professor at Baylor College of Medicine in Houston and a former member of the national board of the American Diabetes Association. "It's a better choice for an overweight diabetic." Dr. Garber ... says he has not consulted for Amylin or Lilly.
OK, so he hasn't taken cash from Lilly or Amylin. But the ADA has taken plenty of cash. Both companies are listed as having given ADA more than $1 million. They're at the very top of its donors list. I'm not suggesting Garber was biased by that cash, just that it would be nice to know that information when former ADA board members endorse drugs. Such endorsements can be powerful.

Lilly hasn't promoted Byetta as a diet drug, but it has benefited from that positioning. Its own site has this to say about the weight loss issue:

Patients taking BYETTA may feel less hungry and eat less. In clinical trials, on average, people lost 5 pounds in 30 weeks, though BYETTA is not a weight loss product.* Some medicines for type 2 diabetes, such as sulfonylureas and insulin, can cause weight gain, while other drugs, such as metformin, do not affect weight ... BYETTA may reduce your appetite, the amount of food you eat, and your weight. No changes in your dose are needed for these side effects.
This, then, explains why Byetta is such a huge hit. People -- especially diabetics -- love to lose weight, and one suspects that it may be being prescribed as an initial therapy instead of an add-on for this reason.

One last question remains, though. Does Byetta really lead to weight loss? Lilly says this:

In clinical trials, on average, people lost 5 pounds in 30 weeks, though BYETTA is not a weight loss product.
The key words are "on average." If you look at page 8 of this document, it describes the trials that Lilly submitted to the FDA when the drug was approved. Only the people on the highest dose lost significant weight, 2.8kg (about 6.2 pounds). Everyone else lost 1.6kg (about 3.5 pounds) or less. And even the people on a placebo lost a little bit of weight.

It's the pancreatitis -- which is still extremely rare in Byetta users -- that's making the headlines, but it may be that crisis which causes doctors to start scrutinizing their use of Byetta a little bit more carefully than perhaps they have in the past.