Imatinib mesylate combined to pegylated interferon alfa 2a (Peg-IFN) has been reported to significantly enhance the molecular responses for de novo chronic phase chronic myeloid leukemia (CP-CML) patients compared to Imatinib alone in a Phase 3 study (Preudhomme et al. NEJM 2010). Second generation tyrosine kinase inhibitors (TKI2) such as nilotinib induce significantly higher levels of cytogenetic and molecular responses than imatinib as front line therapy for CP-CML (Saglio et al., NEJM 2010).
Test the combination of nilotinib + Peg-IFN as front line therapy in CP-CML patients in order to check the safety and evaluate the molecular response rates (EudraCT 2010–019786–28).
In this 2-step French national study, patients were assigned first to Peg-IFN (± HU) for a month at 90 mg/wk prior to a combination of nilotinib 300 mg BID + Peg-IFN 45 mg/wk for ≥ 1 year. The primary endpoint was the rate of confirmed (on 2 datapoints) molecular response 4.5 (MR4.5) by 1 year. Molecular assessments were centralised for all patients and expressed as BCR-ABLIS in %.
In the first cohort, 40+1 patients (1 screen failure) were enrolled and a second cohort of 20 patients was planned once the last patient of cohort 1 attained 1 year of treatment, if the primary endpoint would have not been reached. The current median follow-up is 13.6 (10.1–16.3) months. Sokal and Euro scores were high for 12% and 2%, intermediate for 49% and 55% and low for 39% and 43% of the patients respectively. Euro score was high for one patient. The median age was 53 (23–85) years. Two patients had a masked Philadelphia chromosome, 3 a variant form, and 1 had additional chromosomal abnormalities, all patients had a “major” BCR transcript. Five percent of patients were in CHR at 1 month of Peg-IFN and 100% at month (M) 2 (after 1 month of combination therapy). The rates of Complete Cytogenetic Responses (CCyR) at 3, 6, and 12 months of combination (i. e. at 2, 5, 8 and 11 months of TKI2) were 47%, 71%, 100% respectively on evaluable samples. The incidence of molecular responses are mentioned in figure 1.
Of note, 87% of the patients had a BCR-ABLIS ≤10% at M3. The rates of molecular responses broke down by major molecular response (MMR): 27%, 4 log reduction (MR4): 36%, and ≥4.5 log BCR-ABL reduction (MR4.5, MR5 and undetectable): 21% with a total number of 84% patients in ≥MMR and beyond (17.5% and 67.5% in intention-to-treat respectively) at 1 year. Confirmed molecular results at 1 year will be presented. Nilotinib trough levels centrally analysed at M3, 6 and 12 for the vast majority of patients were ≥ 1000 ng/ml and Peg-IFN did not seem to impact on its pharmacokinetics. One patient went on unmutated myeloid blast crisis at M6 and is alive after allogeneic stem cell transplantation. Four additional patients were withdrawn from study: At M2 for non observance, at M6 for seizures related to an extra-dural hematoma, at M6 for recurrent grade 3 hepatic toxicity, at M9 for recurrent grade 3 pruritus. The median dose of Peg-IFN delivered to the patients during the first month was 90 (0–180) mg/wk, 45 mg/wk at M2, 3, 9, 12, and 33.75 mg/wk at M6. The median doses of nilotinib delivered to the patients were 600 mg daily at M2, 3, 6, 9, 12 and 15 as initially planned. The rate of grade 3–4 hematologic toxicities overall were anemia 2.5%, thrombocytopenia 41%, neutropenia 41% and pancytopenia 5%. These were observed mainly during M2 (16% neutropenia, 24% thrombocytopenia, 3% anemia), M3 (16% neutropenia, 13% thrombocytopenia, 3% pancytopenia) and M6 (12.5% neutropenia, 5% thrombocytopenia) and disappeared thereafter. Grade 3–4 toxicities occurred mostly during the first 3 months with 15% cholestatic episodes, 5% of ALAT elevation, 2.5% of lipase elevation, 2.5% arthro-myalgias, 2.5% abdominal pain without lipase elevation, 2.5% of depression. No PAO was observed and, to date, no dyslipidemia.
The combination of nilotinib and Peg-IFN seems relatively well tolerated despite frequent initial and transient hematologic and hepatic toxicities, and provides very high rates of molecular responses at 1 year and beyond. According to the initial methodology of this trial, the second cohort of patients will not be enrolled as the MR4.5 rates at M12 are beyond the initial expectations. A randomised phase III study testing nilotinib versus nilotinib + Peg-IFN is warranted.
Nicolini:Novartis, Bristol Myers-Squibb, Pfizer, ARIAD, and Teva: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Etienne:Novartis, Pfizer, speaker for Novartis, BMS: Consultancy. Roy:Novartis, BMS: Speakers Bureau. Huguet:Novartis, BMS: Speakers Bureau. Legros:Novartis, BMS: Research Funding, Speakers Bureau. Giraudier:Novartis: Speakers Bureau. Coiteux:Novartis, BMS: Speakers Bureau. Guerci-Bresler:Novartis, BMS: Speakers Bureau. Rea:Novartis, BMS: Consultancy, Speakers Bureau. Gardembas:Novartis: Speakers Bureau. Hermet:Novartis, BMS: Speakers Bureau. Rousselot:Novartis, Pfizer, speaker for Novartis, BMS: Consultancy, Speakers Bureau. Guilhot:Novartis, Ariad, and BMS: Consultancy, Speakers Bureau. Mahon:Novartis, BMS: Consultancy, Speakers Bureau.
Asterisk with author names denotes non-ASH members.