Saturday, June 23, 2007

June 23, 2007 - A Smart Bomb That Could Be In My Future

Searching the Net today, I come across an Associated Press article from about two months ago, about two lymphoma drugs I've heard of, but don't know too much about: Zevalin and Bexxar. These are radioimmunotherapy drugs: a hybrid of radioactive material and genetically-engineered medicine. The gist of the article is that, while these treatments are highly effective against lymphoma, for some inscrutable reason they haven't caught on in a big way. Oncologists have been slow to recommend them to patients. The manufacturers of Zevalin, the article goes on to say, are so disappointed with the sluggish sales that they're seeking another pharmaceutical company to buy the patent from them.

Zevalin and Bexxar work much like Rituxan, in that they target a certain protein, called "CD-20," that's found on the surface of certain types of lymphoma cells (the same type I happen to have, fortunately). The difference is that, instead of chemically neutralizing those cells, Zevalin and Bexxar deliver a tiny particle of radioactive material that accomplishes the same thing. Furthermore, they often bring about longer remissions. The protocol is relatively easy on the patient: just two intravenous infusions, one week apart.

Here's an excerpt from the article:

"The issue: Despite research showing they work well, fewer than 10 percent of lymphoma patients who are candidates for Zevalin and Bexxar ever use them, says Dr. Mark Kaminski of the University of Michigan, a hematologist who co-invented Bexxar.

Why? Specialists cite a complex list of reasons, including that most oncologists aren't licensed to administer the radioactive infusion and must send their patients to a nuclear-medicine doctor. There's also confusion about the risks of radiation, which studies suggest are minimal, and when the drugs work best – early, not as a last-ditch therapy.

‘There's lots of reasons to use them, and there seems to be an inertia against them,' says Dr. Mitchell Smith, lymphoma chief at Fox Chase Cancer Center in Philadelphia. ‘I do see it as unfortunate.'....

‘Basically, [the drug companies] hit a home run' scientifically, says Kaminski. ‘The shock wave that goes through here is that if you can't get this to work in the marketplace, what's the sense of developing anything else along this line?'"

Part of the difficulty, evidently, is the hybrid nature of these drugs. Because they contain radioactive material, the Nuclear Regulatory Commission has to be involved in licensing oncologists to use them. Not many have received that permission, to date. The NRC is used to working with nuclear medicine doctors, not oncologists – yet, this material is delivered through a syringe, not through huge radiology machines in a hospital or clinical setting. And, without a lot of oncologists licensed to give the medications, it's hard for patients to gain access to them.

I remember asking Dr. Carol Portlock, of Memorial Sloan-Kettering, about Bexxar when I was consulting with her at the end of my chemo treatments. She didn't seem too much of a cheerleader for it, at least as a first-line treatment. I remember her saying something about the unknown effects of radiation, years down the road – suggesting that I probably wouldn't want to put radioactive material in my body unless I'd first exhausted all other options. (Of course, I already get radioactive material injected into my veins every time I go for a PET scan.)

For me, this raises questions about the marketing of cancer drugs. A big part of oncologists' profits come from the drugs they sell to patients. Unlike most other medical specialties, oncologists – at least those oncologists who own and operate their own infusion suites – are both physicians and pharmacists to their patients. If there's a drug they're not yet licensed to sell, it's understandably not going to be on their radar screens – at least, not the same way the medications sitting on their shelves are.

Anyway, it will be interesting to see how the thinking about drugs like these may change, in the next few years. If it turns out that my upcoming biopsy indicates a relapse, I wonder if I could be using oncological "smart bombs" like these sooner than I think?

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