Choosing poison

Ok, now for the all-consuming thing: treatment.

In the last week, I've read dozens of websites and probably fifty medical journal articles. Remember, I study science and technology. I founded the UM Science, Technology & Society Program, which also covers medicine. I write about climate modeling, global data networks, and information infrastructure (see my website for more.) So I'm totally at home with ultra-technical subjects I haven't been trained in, and I am a very quick study.

One good thing about having a rare disease is that the number of journal publications is small. Pubmed dredges up only 30 or so articles on hairy cell leukemia since 2000. The National Cancer Institute website offers both a patient version and a health professional version; I read the latter (thanks Mom), which links to dozens of articles.

So. The first-line treatment for HCL is cladribine, aka 2-CdA. Doctors like it because it leads to complete or partial remission in 80-90% of HCL cases. It's administered over 7 days by a pump through a PICC line, a catheter that will run through an artery in my arm all the way to my heart. As chemotherapy drugs go, this one has limited side effects. No vomiting. My hair won't even fall out. (Damn!) On the other hand, about half of all patients get a high fever, caused by blood cell death as the drug does its work.

Two other drugs, pentostatin and alpha-interferon, also work against HCL. Alpha-interferon is out of fashion now. Pentostatin requires a much longer course of treatment — 3-6 months instead of one week — and its success rate is no better than cladribine. So they hold these in reserve in case the cladribine doesn't work.

Two other drugs are in clinical trials now. Rituximab, a monoclonal antibody used widely against B-cell lymphomas, doesn't work very well by itself against HCL, but it's being tried in combination with cladribine to eradicate the dregs of the disease. It kills off all your B-cells; then they grow back from scratch, as it were (if you're lucky). Early results on this combination look extremely good. BL22, a recombinant immunotoxin, consists of an "edited" bacterial toxin attached to a protein that binds to CD22 on the cell surface. It's basically a little mail-bomb that delivers itself, then kills the cell. A newer version of this idea, HA22 — not the deluxe clown shoe, in case you were wondering — is more than twice as toxic to the B-cells without increasing toxicity to the rest of the organism. It's in Phase I.

Every doctor I've talked to is pushing cladribine alone as a first-line treatment. Since my anemia is getting really bad, and the clinical trials of ritux and BL22 are in Texas and Maryland respectively, I don't seem to have much choice — for the present. It's not as simple as it sounds. In another post I'll write about the advice of the Patient from Hell, who's doing rituximab as maintenance therapy for his lymphoma.