Temozolomide and cisplatin in relapsed/refractory acute leukemia

Area of Science:

• Hematology
• Oncology
• Pharmacology

Background:

• O6-methylguanine-DNA methyltransferase (MGMT) plays a role in DNA repair and can confer resistance to alkylating agents like temozolomide.
• Cisplatin is known to deplete MGMT, potentially enhancing the efficacy of temozolomide.
• Acute leukemias, particularly relapsed and refractory forms, present significant treatment challenges.

Purpose of the Study:

• To evaluate the safety and tolerability of a combination regimen of cisplatin and temozolomide in patients with relapsed or refractory acute leukemia.
• To assess preliminary efficacy signals of this combination therapy in a heavily pretreated patient population.

Main Methods:

• A Phase I clinical trial was conducted.
• Participants included patients with relapsed/refractory acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and biphenotypic leukemia.
• Patients received escalating doses of temozolomide (up to 200 mg/m²/day for 7 days) concurrently with cisplatin (100 mg/m² on day 1).

Main Results:

• The combination regimen was well tolerated up to the maximum tested doses.
• One complete remission was observed in the study cohort.
• Twenty-five percent (5 out of 20) of patients showed a significant reduction in bone marrow blasts, suggesting biological activity.

Conclusions:

• The combination of cisplatin and temozolomide is a tolerable regimen for patients with relapsed and refractory acute leukemia.
• The observed reduction in bone marrow blasts warrants further investigation into this combination's efficacy.
• This regimen may offer a therapeutic option for heavily pretreated leukemia patients, potentially by overcoming temozolomide resistance through MGMT depletion.