Approval summary: imatinib mesylate capsules for treatment of adult patients with newly diagnosed philadelphia chromosome-positive chronic myelogenous leukemia in chronic phase.
OBJECTIVE
The purpose is to describe the Food and Drug Administration (FDA) review and approval of imatinib (Gleevec; Novartis Pharmaceuticals, East Hanover, NJ) for treatment of adult patients with newly diagnosed Philadelphia chromosome-positive chronic myelogenous leukemia (CML) in chronic phase.


METHODS
The FDA reviewed data in electronic format from a randomized controlled clinical trial of 1106 adult patients with newly diagnosed Philadelphia chromosome-positive CML in chronic phase, comparing imatinib with the combination of IFN-alpha and cytarabine.


RESULTS
Imatinib showed clinically and statistically significantly better results for time-to-progression to accelerated phase or blast crisis, progression-free survival, complete hematological response rate, and cytogenetic response rate. With a median follow-up of 14 months, a maximum follow-up of 19.5 months, and an expected median survival of 5-6 years on the IFN-alpha/cytarabine control arm, few of the expected progressions to accelerated or blast phase or deaths have occurred. Imatinib was also better tolerated. Edema, nausea, rigors, neutropenia, and headache were more frequent in women. Only 57% of the IFN-alpha target dose was administered, and only 68% of patients received any cytarabine. However, this does not appear to adequately explain the superiority of imatinib observed in this trial. Results of a population pharmacokinetic study in a subgroup of 371 patients and a separate rifampin-imatinib drug-drug interaction study in healthy volunteers are presented.


CONCLUSIONS
On December 20, 2002, imatinib was granted accelerated approval under subpart H, rather than regular approval. Follow-up is short compared with the natural history of chronic phase CML or more mature results with established therapies such as IFN-alpha or transplantation. If imatinib should stop working after 1.5-2 years, the results could be importantly different from the present analysis. As a Phase IV postmarketing commitment, the applicant has agreed to provide follow-up reports on this imatinib study annually for the next 6 years.
Johnson
John R
JR
Division of Oncology Drug Products (HFD-150), Center for Drug Evaluation and Research, United States Food and Drug Administration, Rockville, Maryland 20857, USA. Johnsonj@cder.fda.gov
Bross
Peter
P
Cohen
Martin
M
Rothmann
Mark
M
Chen
Gang
G
Zajicek
Anne
A
Gobburu
Joga
J
Rahman
Atiqur
A
Staten
Ann
A
Pazdur
Richard
R
D000328:Adult; D000367:Age Factors; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D002214:Capsules; D005260:Female; D006801:Humans; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use*; D011743:Pyrimidines / Q000009:adverse effects / Q000627:therapeutic use*; D012737:Sex Factors
D000970:Antineoplastic Agents; D001549:Benzamides; D002214:Capsules; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate