Walking a Tightrope: Dosage Modifications and Treatment Outcomes of All--Retinoic Acid, Arsenic Trioxide, and Daunorubicin for High-Risk Acute Promyelocytic Leukemia.

PURPOSE

The use of all--retinoic acid (ATRA) and arsenic trioxide (ATO) in the treatment of low- and intermediate-risk acute promyelocytic leukemia (APL) is the standard of care. We report the combined use of ATRA, ATO, and daunorubicin (DNR) in patients newly diagnosed with high-risk APL. The primary focus was to describe the drug dosage modifications made in the real-world scenario.

METHODS

In this descriptive study, we included 16 out of 28 patients with high-risk APL from two tertiary care centers in South India (Vijayawada and Trichy) between January 2015 and December 2018. A unique approach of initiating ATRA at a dose of 25 mg/m on day 1 and escalation to 45 mg/m after cytoreduction with DNR and hydroxyurea was followed in all patients to avert differentiation syndrome, in the setting of hyperleukocytosis at presentation.

RESULTS

All patients who survived the first 3 days of admission achieved complete remission after a median duration of 29 days. There were no deaths during induction or consolidation, and the regimen was well tolerated; two patients developed grade 3/4 peripheral neuropathy requiring treatment modification. After a median follow-up duration of 1.9 years, there were no hematologic or molecular relapses.

CONCLUSION

The study sheds light on the modifications made to recommended dosages of ATRA, ATO, and DNR to optimize outcomes in high-risk APL and reaffirms the importance of ATO use in the front-line setting to achieve durable responses with minimal toxicity.