Tasigna® (nilotinib) is superior to Gleevec® (imatinib) for the treatment of patients with Philadelphia chromosome-positive chronic myeloid leukemia (CML), according to the results of two studies presented at the 54th Annual Meeting of the American Society of Hematology in Atlanta, Georgia.
Each year in the United States, approximately 5,000 people are diagnosed with chronic myeloid leukemia (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® (imatinib), 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.
Researchers presented two-year data from the ENESTcmr trial. The study involved 207 patients with Philadelphia chromosome-positive CML-CP who had achieved complete cytogenetic responses but still had persistent BCR-ABL positivity. Patients were were randomized to switch to Tasigna or continue taking Gleevec. The results indicated that significantly more patients treated with Tasigna had undetectable levels of disease—32.7% on Tasigna vs. 16.5% on Gleevec. The researchers concluded that switching to Tasigna led to faster, deeper molecular responses in patients with minimal residual disease on long-term Gleevec.
Researchers presented four-year data from the ENESTnd trial. The phase III study involved 846 adult patients with Philadelphia chromosome-positive CML-CP who were randomized to Tasigna or Gleevec. The study evaluated molecular response rates, time to progression, progression-free survival and overall survival. The results indicated that more than three times as many patients treated with Tasigna as first-line therapy experienced a reduction in the level of disease compared to those treated with Gleevec.
The results of both studies may encourage doctors to switch patients with Philadelphia chromosome-positive CML-CP to Tasigna.
 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.