The occurrence of lymphocytosis was significantly associated with a higher rate of complete cytogenetic response in all phases of CML, and with higher rates of major and deep molecular responses in patients with CML-CP.
“In 1 of the chronic phase studies there seemed to be an effect on disease-free survival, generating the hypothesis that these immune cells, which are being uniquely generated by dasatinib, may be having an effect on the course of the disease,” Schiffer said.
Patients with lymphocytosis from the CA180-034 trial, which had a 7 year follow-up, had significant improvements in both progression-free survival (P = .0119) and overall survival (P = .0349) compared with patients without lymphocytosis.
An analysis of side effects of dasatinib showed that there was a increase in the incidence of pleural effusion among patients with lymphocytosis in all phases of CML, but this increase was only statistically significant among patients with CML in accelerated phase.
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“Among all of this class of drugs, as far as we know, this is the only drug that produces this immune effect,” Schiffer said. “If it can be verified that the immune cells that are generated have an anticancer effect, that would be very important, and one could imagine using it in other circumstances, for example, to see if we could augment the immune effect that comes after stem cell transplantation.”
- Schiffer CA, Cortes JE, Hochhaus A, et al. Lymphocytosis after treatment with dasatinib in chronic myloid leukemia: effects on response and toxicity [published online ahead of print March 21, 2016]. Cancer. doi: 10.1002/cncr.29933.