at 100 percent through 12 months of follow-up. More than half (53 percent) of patients went into complete remission after the first month of therapy, and that figure kept rising to 79 percent after 12 months of follow-up, researchers said. All 19 patients who were followed through their 12 cycles of treatment have achieved what’s known as a “very good partial response,” in which their tumors have shrunk by at least 90 percent.
Side effects were predictable, and mostly mild, by cancer drug standards. About 18 percent of patients had moderate to severe anemia, another 12 percent had moderate to severe depletion of their infection-fighting white blood cells, and 10 percent had a significant drop in platelet cells that help the blood form clots. Six patients dropped out of the study, although only one quit because of toxicity, researchers said. About 24 percent of patients experienced tingling and numbness in fingers and toes (peripheral neuropathy), but those cases were rated only mild to moderate in intensity.
When doctors today use Millennium’s Velcade, patients often complain of nerve tingling and numbness, which prompts doctors to adjust the dosage, or the scheduling of doses, Jakubowiak says. Those tweaks have helped patients, but Jakubowiak says his preference is to keep the dosages high and consistent as long as they are tolerated, to give the patient the best chance at a complete and long-lasting remission.
“The dose manipulations have created some improvements, but nevertheless, it is the big limitation of the Velcade regimen,” Jakubowiak says.
Onyx is evaluating its options for how to build on this small study, by looking at carfilzomib as part of the three-drug combo strategy in a pivotal stage study for newly diagnosed patients, says company spokeswoman Lori Melancon. The company is also in the midst of conducting a pivotal clinical trial of the carfilzomib regimen in relapsed patients.
Jakubowiak says he’s eager to see what scientists can learn from the upcoming trials.
“In my opinion, it’s rare that such a good regimen comes along. The improvement is not a dramatic change, but it’s strong enough that the results are unquestionably better than what we’ve seen before,” Jakubowiak says. “I’d like to build on it.”
