Amgen Cancer Drug Getting Personal, Which May Be a Good Thing for Patients—and Sales

Xconomy Seattle — 

Amgen is preparing to make an unusual argument to an FDA advisory panel tomorrow. The world’s largest biotech company (NASDAQ: AMGN), with research operations in Seattle and Cambridge, MA, plans to make a case that one of its drugs should be used by just a subgroup of patients with colorectal cancer who appear to be most likely to benefit from it.

Normally, drugmakers spend a lot of time and money trying to prove their products should be used by the broadest number of patients possible. This meeting will be closely watched by hundreds of cancer drugmakers, since it could be an important test case for the movement toward creating more personalized cancer medicines.

The hearing will focus on two colorectal cancer drugs that hit the same target that’s a culprit in tumor proliferation, EGFR. The medicines, Amgen’s panitumumab (Vectibix) and Eli Lilly’s cetuximab (Erbitux), have both been shown in backward-looking statistical analyses to work much better for about 40 percent patients with a normal form of a gene called KRAS. If you’re one of the unlucky others with a mutant form of KRAS, which makes cancer more aggressive, the drugs won’t work. Since these treatments are hugely expensive, at $10,000 a month for the Lilly product and $8,000 a month for the Amgen version, there’s a societal interest in genetic testing of these patients before they get treatment. It also could spare a whole lot of people the nasty skin rash and other side effects that come with the drugs, if they have little chance of benefit.

“Amgen has concluded that the benefit/risk profile of panitumumab will be improved by restricting monotherapy use to those patients whose tumors have the wild-type (normal) KRAS gene,” the company said Friday in briefing document posted online.

I’m always skeptical when drug companies say they are eager to narrow down their potential pool of customers, but in Amgen’s case there is a back story of business and science that explains how it arrived at this position.

For starters, the Lilly product got to the market first in February 2004, when it was developed by ImClone Systems. The drug has built a commanding lead in market share, with $1.3 billion in sales last year.

Amgen paid a fortune-$2.2 billion-in 2006 to acquire Fremont, CA-based Abgenix to get full control over the second-in-class contender, panitumumab. But the drug has not emerged as the kind of $2 billion-a-year commercial success originally predicted by analysts. That’s partly because a study in March 2007 was halted when it showed the Amgen drug raised the risk of death in a clinical trial when used in tandem with Genentech’s bevacizumab (Avastin), another colorectal cancer drug that works differently.

That result wrecked Amgen’s marketing strategy, which had been to position panitumumab … Next Page »

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