A phase I study of pemetrexed in patients with relapsed or refractory acute leukemia.
OBJECTIVE
To investigate the toxicity profile, activity, pharmacokinetics, and pharmacodynamics of pemetrexed in leukemia.


METHODS
Patients with refractory or relapsed acute leukemia were eligible. A phase I 3+3 design was implemented. Pemetrexed was infused intravenously (IV) over 25 min with vitamin supplementation. Courses were repeated every 3 to 4 weeks according to toxicity and efficacy. The starting dose of 900 mg/m² was escalated by approximately 33% until the dose-limiting toxicity (DLT) was determined.


RESULTS
Twenty patients with acute myeloid (AML) or lymphocytic (ALL) leukemia received therapy. The main non-hematologic adverse event was liver dysfunction at several dose levels, including 2 DLTs at 3,600 mg/m². One patient with ALL (3,600 mg/m² dose level) achieved a partial response. Pemetrexed pharmacokinetics were linear with escalated dosing. Elevated plasma deoxyuridine was observed in a subset of patients following pemetrexed infusion, but was not correlated with dose levels. Changes in the nucleotide pools of circulating mononuclear cells were observed, but were variable.


CONCLUSIONS
The recommended phase II dose of pemetrexed for future leukemia studies is 2,700 mg/m(2) IV over 25 min every 3 to 4 weeks with vitamin supplementation. Deoxyuridine levels did not increase with increasing pemetrexed dose, suggesting pemetrexed inhibition of thymidylate synthase (TS) may be saturated by the 900 mg/m² dose level. However, no firm conclusion can be made regarding TS saturation in tumor cells. While tolerable, pemetrexed monotherapy had limited activity in this highly refractory population. Exploration of pemetrexed in combination with other active agents in leukemia is a reasonable future endeavor.
Abdel-Karim
Isam
I
San Antonio Cancer Center, San Antonio, TX, USA.
Plunkett
William K
WK
O'Brien
Susan
S
Giles
Francis
F
Thomas
Deborah
D
Faderl
Stefan
S
Ravandi
Farhad
F
Rios
Mary Beth
MB
Du
Min
M
Schneck
Karen B
KB
Chen
Victor J
VJ
Lin
Boris K
BK
Nicol
Steven J
SJ
Kantarjian
Hagop M
HM
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005971:Glutamates / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D006147:Guanine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D006801:Humans; D007938:Leukemia / Q000188:drug therapy*; D008297:Male; D020714:Maximum Tolerated Dose; D008875:Middle Aged; D000068437:Pemetrexed; D012008:Recurrence
D000970:Antineoplastic Agents; D005971:Glutamates; D000068437:Pemetrexed; D006147:Guanine