Given the results of the BELA trial, with the problems of treatment side-effect management realized and seemingly resolved, Elias Jabbour, MD, Assistant Professor of Medicine at The University of Texas MD Anderson Cancer Center, Houston, assumes bosutinib will be approved in chronic myeloid leukemia. In fact, he urges the manufacturer to seek approval earlier rather than later, to avoid the coming crowd of tyrosine kinase inhibitors.

He does have concerns, however, regarding future treatment choices. Bosutinib would be one of four possible options, he said. “In my book, having several options is always better. But what we need to do is find the molecular/genetic factors to help us predict response, and hopefully that will tell us who should receive what,” Dr. Jabbour said in an interview.

For the moment, there are subtle differences in side-effect profiles on which to base treatment decisions. “Dasatinib [Sprycel] can cause pleural effusion, so giving it to a smoker, or a patient with chronic obstructive pulmonary disease would not be appropriate; nilotinib [Tasigna] carries a risk of pancreatitis and other issues, so would not be ideal for diabetics,” he said.

Bosutinib seems to have a cleaner side-effect profile in comparison with these two agents, but the issue overshadowing all three of the newer tyrosine kinase inhibitors is price.

“There’s going to be a real dilemma when imatinib [Gleevec] goes off patent—and that’s soon,” Dr. Jabbour predicted. “Unless we show clear advantage in safety and efficacy compared to imatinib,” payers may balk at the additional cost of novel treatments. ■

Disclosure: Dr. Jabbour has received honoraria from Novartis, Pfizer, and Bristol-Myers Squibb.