Promising frontline triplet regimen for TP53-mutated AML

A triplet combination of 5-azacitidine, venetoclax, and magrolimab displayed promising response rates in newly diagnosed older, unfit, or TP53-mutated patients with acute myeloid leukaemia (AML).

Older or unfit patients were the focus

“Older or unfit patients with AML treated with 5-azacitidine plus venetoclax show overall survival (OS) rates of 40% after 2 years,” said Dr Naval Daver (MD Anderson Cancer Center, TX, USA). “Moreover, patients with TP53-mutated AML treated with hypomethylating agents (HMA) plus venetoclax as first-line therapy display median OS rates of only 5–7 months. Therefore, there is an obvious unmet need in these patients,” Dr Daver argued. The current phase 1/2 trial included 48 patients divided over 3 cohorts:

Patients received cycles (21 days per cycle) of 5-azacitidine (75 mg/m2, once daily, day 1 to 7), venetoclax (400 mg, once daily, day 1 to 21/28), and magrolimab (ramped up to 30 mg/kg, at day 1 and day 11). The overall response rate in older, unfit, or TP53-mutated patients (n=14) was 86%, with a complete response (CR) rate of 64%. In patients with TP53 wildtype (n=11) the overall response rate was 100%, with a CR of 64%.

Absolute neutrophil count and platelet recovery was observed

Furthermore, TP53 variant allele frequency (VAF) levels were significantly decreased in TP53-mutated patients who displayed a CR. This indicates biologic activity at the TP53 level. Among venetoclax-naïve patients and patients with prior venetoclax therapy, the CR rates were 38% and 0%, respectively. Notably, absolute neutrophil count and platelet recovery were robust after 28 days, which is an encouraging result in triplet therapy for AML. According to Dr Daver, the safety profile of the current triplet regimen was similar to the safety of an HMA plus venetoclax regimen, with febrile neutropenia and lung infections as most common serious adverse events. 

References:
1. Daver NG, et al. Phase I/II Study of Azacitidine, Venetoclax and Magrolimab for Newly Diagnosed and Relapsed/Refractory AML. O616, ASH 2021 Scientific Sessions, 11–14 December.