ZymoGenetics said today it has started a clinical trial of Interleukin-21 along with Rituxan, as a combination therapy against non-Hodgkin's lymphoma.
Combination cancer drugs are somewhat in vogue as a way companies can show the FDA their treatments offer an edge in efficacy. If it works, the combination is bound to give health insurers headaches -- Rituxan alone typically costs more than $14,000 per patient in a usual four-week course, according to Mosby's Drug Consult. Adding another complex, genetically engineered protein like IL-21 would surely dial up the price.
For its part, ZymoGenetics is still a long way from delivering IL-21 to the market, much less driving a hard bargain with insurers over price. It is starting the early-stage trial based on some intriguing results it saw in mice.
The company said in December at the American Society of Hematology's annual meeting that 70 percent of mice on the Interleukin-21 and Rituxan combo survived at least three months with aggressive lymphoma, compared to 10 percent of mice on the same dose of Rituxan alone.
ZymoGenetics thinks that the combination might work because IL-21's mechanism of action is complementary to Rituxan's. IL-21 is an engineered protein that stimulates two types of immune system cells, Killer T cells, and Natural Killer cells. It is believed those cells could essentially pile on, battering tumors while Rituxan does its job of latching onto the tumor cells, and recruiting other immune system cells to attack.
ZymoGenetics' chief scientific officer Doug Williams said the company is focused on how IL-21's mechanism of action complements Rituxan, not how the U.S. health system might pay for such a mix. "If you provide a marginal benefit, you might get some pushback (from insurers)," Williams said. "But if you could bring considerable improvement, then you've got an argument that can be made to justify whatever the price may be."
If the combo doesn't work, ZymoGenetics could keep trying IL-21 as a single agent in other diseases, like kidney cancer and melanoma, where trials already are underway. Or, Williams said, it could test IL-21 in some other combination with Nexavar or Sutent, two new drugs for kidney cancer.
Then again, those drugs aren't cheap either, at $7,800 for a 28-day supply of Sutent, and $5,400 for a 30-day supply of Nexavar, according to Mosby's.
Of course, if IL-21 can extend lives without any extra help, ZymoGenetics and insurers would both be happier.