Changing therapy from Glivec® to a "copy" imatinib results in a worsening of chronic myeloid leukemia disease status: two case reports

INTRODUCTION Imatinib mesylate (Glivec((R))/Gleevec((R))) is the standard first-line therapy for the treatment of chronic myeloid leukemia due to its high hematologic, cytogenetic, and molecular response rates and favorable long-term safety profile. A copy version of imatinib is currently available in several countries. We report on two cases of CML who were originally treated with Glivec in Egypt and subsequently switched to the copy drug CASE PRESENTATION Case one was a 35-year old female with chronic myeloid leukemia in blast crisis who began treatment with combination chemotherapy and Glivec. The patient achieved and maintained a complete hematologic response and continued on Glivec 400 mg/day. In March 2007, she was switched to the copy drug In September 2007, the patient presented in hematologic relapse. At this time, treatment with chemotherapy in combination with Glivec 400 mg/day was resumed. The patient quickly achieved, and maintained, complete hematologic response on Glivec 400 mg/day. The second patient was a 64-year old male with chronic myeloid leukemia in blast crisis who began treatment with truncated chemotherapy in combination with Glivec 400 mg/day. After 6 months, the patient achieved a partial hematologic response and continued on alternating cycles of chemotherapy with continuous administration of Glivec 400 mg/day. The patient received Glivec from January 2006 to February 2007, after which time he was switched to the copy drug. In November 2007, he presented with upper gastrointestinal bleeding and multiple gastric erosions and died the same day. CONCLUSION The safety and efficacy of the copy drug has not been established in randomized clinical trials. It is unknown whether patients, who respond to Glivec and then switch to copy versions of imatinib, will tolerate the copy drug and maintain their response.