Failure of a non-authorized copy product to maintain response achieved with imatinib in a patient with chronic phase chronic myeloid leukemia: a case report.

INTRODUCTION: Due to high rates of response and durable remissions, imatinib (Glivec((R)), or Gleevec((R)) in the USA; Novartis Pharma AG) is the standard of care in patients with chronic myeloid leukemia. Recently, a non-authorized product which claims comparability to imatinib has become available. CASE
PRESENTATION: This report describes the loss of response in a 36-year-old male patient with chronic-phase chronic myeloid leukemia who had previously been in full hematologic and cytogenetic remission and partial molecular remission for three years, under treatment with brand-name imatinib of 400 mg per day. Before the initiation of treatment with a copy product, imatib (CIPLA-India), the patient had negative BCR-ABL status. Within three months of initiation of treatment with the copy product, the patient's BCR-ABL status became positive, with substantial decreases noted in white blood cell counts, red blood cell counts and platelet counts. Conversion of the BCR-ABL status to negative and improvements in hematologic parameters were achieved when the brand medication, imatinib, was resumed at a dose of 600 mg per day.
CONCLUSION: In our patient, the substitution of a copy product for imatinib resulted in the rapid loss of a previously stable response, with the risk of progression to life-threatening accelerated phase or blast crisis phase of the disease. Without supportive clinical evidence of efficacy and safety of imatib (or any other copy product) caution should be used when substituting imatinib in the treatment of any patient with chronic myeloid leukemia.