with that disease who enrolled in the Calistoga study who were very sick—having received a median of five prior rounds of therapy and yet still having bulky tumors. Even so, all 51 of the evaluable patients had some degree of tumor shrinkage, researchers said. About 80 percent of patients saw their tumors shrink by half or more. And these partial remissions do appear to last, as about 60 percent of patients still had no evidence their tumors had started to grow again after a year of follow-up, Gallagher says. Details are being presented today at the hematology meeting by Richard Furman of Weill Cornell Medical College in New York.
A similar story played out in patients with slow-growing or “indolent” non-Hodgkin’s lymphoma. About 63 percent of patients had their tumors shrink by at least half, based on results of 30 people who had received a median of four prior rounds of treatment. Again, a majority of patients saw those partial remissions endure for more than a year, and researchers are continuing to follow up patients to see how long they last. Some patients in this group did see an increase in liver enzymes early in their course of therapy—which can be a red flag of liver damage—although researchers said they were able to reverse the build up of liver enzymes by taking patients off the drug, and putting them back on therapy later at lower doses.
Based on this experience, Calistoga has zeroed in on an ideal dose of 150 milligrams taken twice a day, after experimenting as high as 350 milligrams earlier in the study and seeing no extra benefit.
Since this study wasn’t designed to randomly assign patients to the Calistoga therapy and something else, it’s impossible to say for sure how much of an improvement this treatment represents over the standard of care. While it’s always a bit dubious to compare one clinical trial to another because each uses different criteria, Calistoga’s main benchmark will probably be GlaxoSmithKline’s ofatumumab (Arzerra). That drug has shown that it can shrink tumors in about 42 percent of relapse patients with chronic lymphocytic leukemia, with a median duration of response of 6.5 months, according to the drug’s prescribing information.
The combination study is still in its very early days, but like the other Calistoga study, it is showing encouraging results right off the bat. The first 20 out of as many as 84 patients have been enrolled to get the Calistoga pill in combination with rituximab (Rituxan) or bendamustine (Treanda). The patients had relapsed or treatment-resistant forms of chronic lymphocytic leukemia and indolent non-Hodgkin’s lymphoma.
All six of the first patients with indolent non-Hodgkin’s lymphoma who had gotten two prior rounds of therapy saw their tumors shrink at least by half (one had a complete eradication of tumors) when they got the Calistoga drug in combination with bendamustine. Just like in the other trial, some patients
