Results of an 18-month evaluation in patients with newly diagnosed chronic myeloid leukemia in chronic phase (CML-CP) presented during the Oncology Nursing Society 36th Annual Congress continue to confirm the superior efficacy of nilotinib to imatinib. Although imatinib has long been considered the standard of care for the frontline treatment of CML-CP, clinical evidence shows some patients have inadequate response, develop resistance, or develop intolerable side effects.
The FDA recently approved nilotinib, a potent and selective inhibitor of BCR-ABL, for patients with newly diagnosed CML-CP. This approval was based on results of ENESTnd (Evaluating Nilotinib Efficacy and Safety in Clinical Trials of Newly Diagnosed Philadelphia chromosome-positive CML patients), a multicenter, randomized, open-label, controlled phase 3 study comparing the safety and efficacy of frontline nilotinib with imatinib, noted Gerry Gorospe, Division of Hematology and Hematopoietic Cell Transplantation, City of Hope, Duarte, California, and international colleagues from ENESTnd.
In ENESTnd, patients with newly diagnosed CML-CP were randomized to nilotinib 300 mg (n=282) or 400 mg twice daily (n=281) or imatinib 400 mg once daily (n=283). Efficacy was determined by major molecular response (MMR, a 3-log reduction in BCR-ABL transcripts), complete cytogenetic response (CCyR), disease progression to advanced phases of disease, and overall survival.
“With continuing developments in the treatment of CML, oncology nurses must keep current on new study developments that enhance patient care,” Gorospe said. Over the past decade, three new tyrosine kinase inhibitors have been developed, which have provided safer and more efficacious treatment options for patients with CML. Familiarity with trial results and new monitoring techniques allows oncology nurses to educate patients appropriately on goals of therapy, recognition and prompt reporting of AEs, while allowing for better management of treatment expectations.
Understanding treatment response criteria also assists the nurse to determine patient response to therapy or identify and address issues with adherence. For example, patients who are less adherent with CML therapy have poor long-term outcomes and incur significantly more CML- and health care-related costs.
Long-term efficacy and safety evaluation of nilotinib is ongoing, Gorospe said. With a median follow-up of 18 months, best overall rates of MMR and CCyR were significantly higher in both nilotinib arms compared with the imatinib arm. Significantly more patients in both nilotinib arms (300-mg twice daily and 400-mg twice daily) achieved undetectable BCR-ABL levels than patients in the imatinib arm.
Results also showed that rates of progression to advanced phase and blast crisis were significantly lower for the nilotinib arms versus the imatinib arm. Overall survival was also higher for both nilotinib arms compared with imatinib. Both nilotinib and imatinib were well-tolerated. Discontinuations due to adverse events were lowest for nilotinib 300 mg twice daily compared with nilotinib 400 mg twice daily and imatinib.