Adult patients with Philadelphia chromosome-positive chronic myeloid leukaemia (Ph+ CML) in chronic phase who are treated with Tasigna® (nilotinib) have deeper levels of response compared to those treated with Glivec® (imatinib), according to research presented today at the 53rd Annual Meeting of the American Society of Haematology (ASH) in San Diego.
ENEST (Evaluating Nilotinib Efficacy and Safety in clinical Trials) is the first exploratory randomised trial to investigate the impact of switching adult patients with residual disease after a minimum of two years of treatment with Glivec to Tasigna.
The study showed that twice as many patients switched to Tasigna 400mg twice a day achieved undetectable Bcr-Abl levels by 12 months compared to Glivec (23% taking Tasigna 400mg twice daily and 11% taking Glivec 400mg or 600mg once daily; p=0.0202).
The primary endpoint, which is more stringent than conventional measures, is undetectable Bcr-Abl level in two consecutive samples.
Samples with any detectable level were not considered to be in complete molecular response (CMR).
The lowest detected Bcr-Abl value was 0.00073%. This endpoint showed a two-fold difference in confirmed undetectable CMR for 13% of patients on Tasigna versus 6% of patients on Glivec, although statistical significance was not achieved (p=0.108). The study has a planned follow-up of four years.
After 36 months of follow-up, data from the Phase III ENESTnd clinical trial in adult patients with newly diagnosed Ph+ CML in chronic phase continued to show significantly more patients achieved CMR, defined in this study as at least a 4.5 log reduction from baseline or a trace amount of 0.0032% or less of Bcr-Abl compared to Glivec (32% taking Tasigna 300mg twice daily and 15% taking Glivec 400mg once daily).
The ENESTnd study also continued to show that first-line treatment with Tasigna resulted in significantly fewer patients progressing to advanced phase and blast crisis (AP/BC) stages of disease compared to Glivec, leading to a significantly lower number of CML-related deaths in patients taking Tasigna versus Glivec (p=0.0356).
“Data from both ENESTnd and ENESTcmr reinforce that patients taking Tasigna have a greater chance of achieving CMR, the deepest level of response measurable today, compared to those taking Glivec,” said Timothy P. Hughes, MD, ENEST study investigator and Clinical Professor at the University of Adelaide, Australia.
“We are encouraged by what we saw in ENESTcmr and further follow-up on both trials should help to determine if more patients can reach undetectable levels of CML over time, which could have important implications for determining criteria for future studies on discontinuation of therapy.”