Incidence and Mortality of Second Malignancies In 559 Patients with Chronic Myeloid Leukemia (CML) Treated with Imatinib Frontline: Data From the GIMEMA CML Working Party

Imatinib is the standard of care for CML in early chronic phase. Until now, even in stable complete molecular response, discontinuation of imatinib is not recommended, and imatinib remains a life-saving drug to be taken chronically. Long term side effects, including the incidence of second malignancies, represent a potential relevant issue. Roy et al (Leukemia 2005) reported an unexpected incidence of second neoplasms in patients treated with imatinib after interferon (6/189 patients, 3.2%; urinary tract cancer: 4/6). In contrast, an analysis performed by Novartis Pharma (Pilot et al, Leukemia 2006) on 9518 patients treated with imatinib (including pre-treated patients) did not provided evidence for an increased overall incidence of second malignancies. According to epidemiologic data (Registro Tumori) in Italy, the annual incidence of neoplasms varies from 1%, in the range of age between 50 and 69 years, to 3% for patients over 70 years. AIM. To evaluate the incidence of second malignancies in CML patients treated with imatinib frontline. METHODS. Overall, 559 patients have been enrolled in 3 concurrent clinical studies of the GIMEMA CML Working Party: CML/021, Imatinib 800 mg in intermediate Sokal risk patients (Clin Trials Gov. NCT00514488); CML/022, Imatinib 400 mg vs 800 mg in high Sokal risk patients (Clin Trials Gov. NCT00510926); CML/023, observational, Imatinib 400 mg. We evaluated the incidence of II malignancy notified as severe adverse events reported by the GIMEMA clinical Centers. RESULTS. The median age at the diagnosis of CML was 52 (extr.18 – 84) years; 308 patients (55%) were ≥ 50 years. The median follow-up is currently 60 months. Eighteen patients (3.2%) developed a second malignancy at a median time of 20 months (extremes 2 – 52) from the start of imatinib therapy (Table 1); 4 of these malignancies (2 colon cancer and 2 NHL) were diagnosed within 6 months. All patients were older than 50 years (median 64, extremes 50 – 79) at the diagnosis of the second malignancy. Fifteen out of the 559 (2.7%) patients died due to second neoplasm progression. CONCLUSION. In this multicentre nation-wide experience of CML patients treated with imatinib frontline, the incidence of life-threatening or requiring hospitalization secondary neoplasms (severe adverse events), seems not to be superior to the observed incidence of neoplasm in the Italian national population. In particular, in contrast to what previously reported, no increased incidence of urinary tract cancer was observed.

Gugliotta: Novartis: Honoraria. Castagnetti: Novartis: Honoraria; Bristol Myers Squibb: Honoraria. Martinelli: Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Pfizer: Consultancy. Pane: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Saglio: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Baccarani: Novartis: Consultancy, Research Funding, Speakers Bureau; Bristol Myers Squibb: Consultancy, Research Funding; Wyeth: Consultancy, Research Funding. Rosti: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Honoraria, Speakers Bureau; Roche: Speakers Bureau.