Randomized phase 2 trial of CPX-351 vs. CLAG-M (cladribine, cytarabine, G-CSF, and mitoxantrone) for medically unfit adults with acute myeloid leukemia or other high-grade myeloid neoplasms.

Even with new drugs available, how best to treat unfit adults with acute myeloid leukemia (AML) remains uncertain. In a previous trial in such patients, we found high-dose cytarabine-based therapy with CLAG-M yielded higher response rates but no more toxicity than lower-intensity therapy with dose-attenuated CLAG-M. Here, we conducted a single-institution phase 2 trial (NCT04195945) randomizing 60 adults with untreated AML and medical unfitness with Treatment-Related Mortality (TRM) score of ≥13.1 (68% with ECOG performance status 3-4) 1:1 to standard-dose CPX-351 or CLAG-M. Primary endpoint was 3-month overall survival (OS); key secondary endpoints included overall response rate, rate of measurable residual disease (MRD) negativity, toxicity/mortality rates, and survival estimates. Only CLAG-M met the primary endpoint of ≥63% 3-month OS (70% vs. 60%; P = 0.41), and CLAG-M therapy was associated with a non-significantly higher complete remission (CR) plus CR with incomplete hematologic recovery rate (73% vs. 47%, P = 0.064). Nonetheless, there was no statistically significant difference in relapse-free survival following CLAG-M vs. CPX-351 (median 37.6 vs. 19.9 months; P = 0.80) or OS (median 10.5 vs. 5.8 months; P = 0.76). In patients with proliferative disease, however, OS following CLAG-M was longer (median 18.5 vs. 3.9 months; P = 0.02) suggesting a role for intensive therapy in this patient subset.