34P Efficacy and toxicity analysis of imatinib in newly diagnosed patients of chronic myeloid leukaemia: 18-years’ experience at a single large-volume centre

Imatinib (IM) remains a path-breaking treatment for chronic myeloid leukaemia (CML). We report 18 years of experience in treating patients of CML with IM at a single large-volume centre. A retrospective analysis of 158 CML adult patients who received IM from September 2002 until August 2009 was done. Response (hematologic), progression-free survival (PFS) and toxicity were evaluated. RT-PCR was established in our institute in 2011; before that, its documentation was few and far between. On progression, dose of IM was sequentially increased to 600mg and 800mg. At a median follow up of 15.1 years, analysis of 132 patients was done; 26 (16.7%) lost to follow-ups were excluded from the analysis. Median Age at presentation was 37 (IQR 30-45), with a slight female skew (54%). The most common presentation was fatigue (41%) and abdominal fullness (23%), median haemoglobin was 9.6 gm/dl (IQR 8.4-11.3), and total leucocyte count 92 X 103 (IQR 32.2 X 103 - 15.7 X 104). Mean time to complete haematological response (CHR) was 2.6 months (S.D +0.7 months), and complete cytogenetic response (CCyR) was documented in 81.3%. Of the analysed, 58 (43.9%) progressed (loss of either CHR or CCyR) on IM 400, in these the dose of IM was escalated. Mean PFS on IM 400 was 146.4 months (95% CI; 131-161). On IM 600, 25 (43.1%) progressed and were started on IM 800; of these, 9 (36%) progressed on IM 800mg and were shifted to second-line tyrosine kinase inhibitors (TKI). Haematological toxicity was seen in 32 (24%) patients; non-haematological side effects were seen in 36 (27.3%), both most commonly in first two years. Grade III or IV side effects were rare. At the time of analysis, 6 (4.6%) had progressed to blast crisis. This 15.1-year median follow up has shown that IM is a highly effective and safe drug for first-line treatment of CML-CP. It is phenomenal in inducing CHR and CCyR with a safety profile to envy. For patients progressing on IM 400, the dose can sequentially and subsequently be increased to 600 and 800, with acceptable toxicity. This data should benefit low- and middle-income countries where second-generation TKIs are not a financially feasible option upfront.