The benefits were also achieved with significantly less grade 3-4 liver toxicity than observed in the GIMEMA study (<10% vs 63%).
There was, however, an excess of cardiac toxicity in course 2 with arsenic trioxide plus all-trans retinoic acid, compared with all-trans retinoic acid and idarubicin (P = .001).
“We’re not totally sure what that’s all due to, but it doesn’t look to be due to a QC prolongation,” he said.
The arsenic trioxide plus all-trans retinoic acid regimen was associated with significant reductions in supportive care requirements including fewer blood and platelet transfusions, days on antibiotics, and days in hospital, with “many patients treated exclusively as outpatients,” he added.
The low risk of relapse with arsenic trioxide plus all-trans retinoic acid also negates the need for minimal residual disease monitoring.
Finally, compared with the GIMEMA study protocol, the attenuated arsenic dosing schedule in AML17 APL resulted in less frequent dosing of arsenic trioxide (63 doses vs. 140 doses) and less drug required (151 vials vs. 280 vials for a 70-kg patient). At an acquisition cost of £350 per vial, this represents a cost savings of £46,000 (nearly $72,000) per patient, not to mention the added convenience to patients, Dr. Burnett observed.
Cancer Research U.K. funded the study. Cephalon provided the arsenic trioxide. Dr. Burnett disclosed part-time employment with CTI LifeSciences and in the last 12 months serving on the advisory boards of Celgene, Agios, Pfizer, and Bristol-Myers Squibb.