Switching Cancer Drugs Could Result in Higher Remission Rates

New findings show that remission rates are consistently higher than 50% when patients with leukemia switch treatment from Glivec (imatinib) to Tasigna (nilotinib), regardless of the reasoning for the switch.

Novartis recently announced these findings from the ENESTop Treatment-free Remission study at the 58^th American Society of Hematology Annual Meeting and Exposition, according to a press release from the company.

Included in the phase 2 clinical trial were 163 patients with Philadelphia chromosome-positive chronic myeloid leukemia (CML), with 126 patients stopping treatment with Glivec due to intolerance, resistance, or physician preference. Investigators stopped the evaluation after patients achieved sustained deep molecular response after 1 year of treatment with Tasigna that was not experienced while taking Glivec.

Results from a post-hoc analysis were recently presented at the conference, Novartis reported.

"Findings from this post-hoc analysis of ENESTop suggest that the reason for switching from Glivec to Tasigna did not impact a patient's chance of maintaining TFR," said Timothy P. Hughes, MD, ENESTop study investigator, Cancer Theme Leader at the South Australian Health and Medical Research Institute and Clinical Professor at the University of Adelaide, Australia. "CML is considered a chronic disease due to the success of tyrosine kinase inhibitors (TKIs), but there remains a need for continued advancements and these findings are an exciting and important contribution to clinical research in CML treatment."

The researchers evaluated the rates of treatment-free remission after 48 weeks since the last treatment, which included 125 patients. Patients were divided into subgroups based on their reason for switching to Tasigna.

The investigators found that more than 50% of patients in the subgroups maintained treatment-free remission status at the time of the study. The proportion of patients maintaining remission at week 48 was similar across the subgroups, according to the study.

At week 48, 58.8% of patients were intolerant to Glivec, 53.3% of patients were resistant to Glivec, and 61.4% of patients in the physician preference subgroups maintained treatment-free remission.

ENESTop is part of a more expansive Tasigna treatment-free remission (TFR) clinical trial program that analyzes the potential to maintain remission after stopping treatment in patients with Philadelphia chromosome-positive chronic myeloid leukemia. In the primary analysis of ENTESTop, 57.9% of patients who achieved deep molecular response after 3 years of treatment maintained a molecular response after 48 weeks of stopping treatment, according to Novartis.

The safety profile of Tasigna was consistent, and there were no new adverse events noted. Also, no patients in these trials advanced while on treatment.

Novartis warns that stopping treatment is not clinically recommended, and should only be done in a clinical study. These studies are ongoing with a set follow-up period to analyze the ability for patients to sustain remission after discontinuing treatment with Tasigna.

"Our mission at Novartis is to help transform cancer therapy through bold science and innovation, and there is no better example of this than our support of eight TFR studies in patients with CML," said Bruno Strigini, CEO of Novartis Oncology. "Our further exploration of results from the ENESTop trial, beyond the primary analysis, reinforces our ongoing commitment to CML patients and contributes to the growing body of science that goes into treating this cancer."