# Reawakening Differentiation Therapy in Acute Myeloid Leukemia: A Comprehensive Review of ATRA-Based Combination Strategies

## TL;DR

This review explores how combining ATRA with other drugs can improve differentiation therapy for AML beyond its success in APL.

## Contribution

The paper systematically reviews pre-clinical and clinical evidence for ATRA-based combination therapies in AML, identifying novel synergistic agents and mechanisms.

## Key findings

- ATRA combined with arsenic trioxide or epigenetic modulators achieves high remission rates in APL and select AML subtypes.
- Pre-clinical studies show synergistic differentiation when ATRA is combined with CDK inhibitors, Bcl-2/MDM2 inhibitors, and proteasome inhibitors.
- Combination therapies modulate signaling pathways, stabilize RARα, and interfere with nucleotide metabolism to enhance differentiation.

## Abstract

All-trans retinoic acid (ATRA) is an established differentiation therapy for acute promyelocytic leukemia (APL), but its effect in other acute myeloid leukemia (AML) subtypes is limited. This single-author review summarizes current evidence on combination strategies designed to enhance ATRA-induced myeloid differentiation. A PubMed search using the keywords “ATRA,” “myeloid,” and “differentiation inducer or enhancer” identified over 500 published studies as of November 2025. Clinical trials demonstrate that ATRA with arsenic trioxide or epigenetic modulators induces high remission rates in APL and select AML subtypes. Pre-clinical studies reveal synergistic differentiation when ATRA is combined with Cyclin-Dependent Kinase (CDK) and kinase inhibitors, nucleotide synthesis inhibitors, DNA-damaging drugs, B-cell lymphoma 2 (Bcl-2)/Mouse double minute 2 homolog (MDM2) inhibitors, proteasome inhibitors, cytokines, glycosylation modifiers, or natural and antibiotic-derived compounds. Mechanisms include modulation of signaling pathways, chromatin remodeling, RARα stabilization, and interference with nucleotide metabolism. These findings support further clinical investigation of ATRA-based combination therapies beyond APL.

(1) Background: All-trans retinoic acid (ATRA) has transformed the treatment of acute promyelocytic leukemia (APL) by inducing terminal myeloid differentiation. However, its efficacy in non-APL acute myeloid leukemia (AML) is limited. Exploring combination strategies that enhance ATRA-induced differentiation may broaden its therapeutic potential. (2) Methods: A literature search of PubMed using the keywords “ATRA,” “myeloid,” and “differentiation inducer or enhancer” identified more than 500 published papers as of November 2025. Pre-clinical and clinical studies were reviewed, with a focus on mechanisms, combination partners, and translational relevance. (3) Results: Clinical evidence confirms that ATRA combined with arsenic trioxide or epigenetic modulators achieves high remission rates in APL and selected AML subtypes. Pre-clinical studies show synergistic differentiation effects when ATRA is combined with CDK and kinase inhibitors, nucleotide synthesis inhibitors, DNA-damaging agents, Bcl-2/MDM2 inhibitors, proteasome inhibitors, cytokines, glycosylation modifiers, natural products, and antibiotic-derived compounds. Mechanistically, these combinations modulate key signaling pathways (MAPK, Akt, JAK/STAT), stabilize RARα, remodel chromatin, and perturb nucleotide metabolism. Although translation to non-APL AML remains limited, these findings provide a rational basis for future clinical trials. (4) ATRA-based combination therapies represent a promising strategy to extend differentiation therapy beyond APL. This review, authored solely by the investigator, highlights molecular targets and potential enhancers warranting further clinical evaluation in AML.