Tasigna® (nilotinib) remains superior to Gleevec® (imatinib) for the treatment of patients with Philadelphia chromosome-positive chronic myeloid leukemia (PH+CML), according to the results of the six-year update from the ENESTnd trial which were presented at the 56th annual meeting of the American Society of Hematology (ASH) in San Francisco. These data are consistent with that previously reported for the ENESTnd trial at two and four years and provide further evidence of the consistent clinical profile of Tasigna as a leading treatment in newly diagnosed patients.
Each year in the United States, approximately 5,000 people are diagnosed with CML. Most cases of CML are characterized by a chromosomal abnormality—the Philadelphia chromosome—in which genetic material is exchanged between chromosome 9 and chromosome 22. This exchange brings together two genes: BCR and ABL. The combination of these two genes into the single BCR-ABL gene results in the production of a protein that contributes to uncontrolled cell growth.
Recognition of the pivotal role of the BCR-ABL protein in CML led to the development of Gleevec which blocks the activity of this protein. Gleevec produced high rates of remission among patients with chronic-phase CML and dramatically changed the treatment of this disease. Tasigna is a newer drug that targets the BCR-ABL protein—and researchers have been evaluating whether it may produce superior outcomes.
The ENESTnd (Evaluating Nilotinib Efficacy and Safety in Clinical Trials – Newly Diagnosed Patients) clinical trial is a Phase III multicenter study directly comparing Tasigna and Gleevec in adult patients with newly diagnosed Ph+ CML in chronic phase. The ENESTnd study directly compares Tasigna 300 mg twice daily to Tasigna 400 mg twice daily or Gleevec 400 mg once daily and is being conducted at 217 global sites and has 846 patients enrolled.
In order to evaluate the effectiveness of treatment the researchers measured the major molecular response (MMR) at 12 months and the durable MMR at 24 months. MMR was defined in this study as 0.1% or less of BCR-ABL.
Patients have now been enrolled in this trial up to six-years and the results demonstrate higher rates of MMR and a reduced risk of CML disease progression compared to Gleevec. There have been fewer progressions to accelerated phase/blast crisis (AP/BC) with Tasigna versus Gleevec. Overall 16 patients treated with Gleevec had CML-related deaths, compared to 10 on Tasigna. The estimated rates of patients whose disease did not progress to AP/BC on study at 72 months in the Gleevec, Tasigna 300 mg and Tasigna 400 mg twice-daily arms were 92.2%, 95.8% and 97.8%, respectively.
The estimated rates of freedom from death due to a CML-related cause at 72 months in the Gleevec®, Tasigna 300 mg and Tasigna 400 mg treatment groups were 93.9%, 97.7% and 98.5%, respectively demonstrating all three treatments to be highly effective and suggesting Tasigna 400 mg may be the optimal treatment for newly diagnosed patients with chronic phase CML.
 Hughes TP, Lipton JH, Spector N, et al. Switching to Nilotinib Is Associated with Continued Deeper Molecular Responses in CML-CP Patients with Minimal Residual Disease After 2 Years On Imatinib: Enestcmr 2-Year Follow-up Results. Blood (ASH Annual Meeting Abstracts) 2012 120: Abstract 694.
 Kantarjian HM, Kim DW, Issaragrisil S, et al. Enestnd 4-Year (y) Update: Continued Superiority of Nilotinib Vs Imatinib in Patients (pts) with Newly Diagnosed Philadelphia Chromosome–Positive (Ph+) Chronic Myeloid Leukemia in Chronic Phase (CML-CP). Blood (ASH Annual Meeting Abstracts) 2012 120: Abstract 1676.
 Larson R, et al. Efficacy and Safety of Nilotinib (NIL) vs Imatinib (IM) in Patients (pts) With Newly Diagnosed Chronic Myeloid Leukemia in Chronic Phase (CML-CP): Long-Term Follow-Up (f/u) of ENESTnd. Poster Presentation. Abstract #4541.