Shorter Course of Venetoclax Misses Noninferiority Bar in AML

A 14-day venetoclax schedule paired with azacitidine did not prove noninferior to the standard 28-day regimen for inducing remission in older adults with newly diagnosed acute myeloid leukemia (AML), according to results from the phase 2 OPTI-AML trial (NCT03013998) published in Blood.¹ However, the gap in complete remission (CR) rates between the 2 schedules was not statistically significant, leaving clinicians without a clean answer on whether a shorter, potentially less toxic option is safe to use across the board.

The findings arrive as health systems continue to grapple with the real-world toxicity of venetoclax-azacitidine, the regimen that became standard of care for older or unfit patients with AML after the pivotal VIALE-A trial (NCT02993523) showed it extended median overall survival (OS) to 4.7 months compared with 9.6 months for azacitidine alone.² Howeer, that 28-day venetoclax schedule was adopted without formal dose-optimization studies, and real-world experience has shown it is difficult to deliver without triggering dose reductions and cycle delays.^2,3

Why the Shorter Course Fell Short on Paper

OPTI-AML, conducted within the multicenter Beat AML Master Trial (NCT03013998), randomized 169 patients 60 years and older with newly diagnosed AML who were ineligible for intensive chemotherapy to receive azacitidine with either 28 days (AV28; n = 83) or 14 days (AV14; n = 86) of venetoclax during the first 2 treatment cycles. The trial was powered to test whether AV14 was noninferior to AV28 using a prespecified margin of 10 percentage points, with CR at any point during the first 2 cycles as the primary end point.

CR was achieved in 49.4% of patients on AV28 vs 43.0% on AV14, a difference of 6.4 percentage points. Because the upper bound of the 90% CI for that difference reached 19 percentage points, exceeding the 10-percentage-point margin, the study did not meet inferiority criteria. At the same time, the CR rate difference was not considered statistically significant, an outcome the investigators attributed partially to underpowering. Their investigation assumed that AV14 might outperform AV28 on the strength of faster count recovery, but the data did not bear this out.

Composite CR, which included CR with incomplete or partial hematologic recovery, favored the longer schedule—80.7% with AV28 vs 68.6% with AV14—while measurable residual disease (MRD) negative status among responders was close to equal between the arms, at 77.6% vs 76.5%, respectively. Safety findings were also similar: grade 3 or higher adverse events (AEs), serious AEs, and 30- and 60-day mortality did not differ meaningfully by arm, although median OS favored AV28, at 21.4 months vs 13.6 months.

What Do These Findings Mean for AML Treatment Strategy?

Among patients who had NPM1 or IDH2 mutations, CR rates were substantially higher with the 28-day regimen (60.9% vs 33.3%), as were composite CR rates (87.0% vs 73.3%). Further, the CR rate was 45% in both arms for patients who did not have these mutations. The authors note this distinction matters because NPM1- and IDH2-mutated AML represent a minority of cases, meaning a large share of the unfit AML patient population may tolerate a shortened venetoclax without sacrificing remission rates, while a genomically defined subset may need the full exposure to achieve the same benefit. Again, the authors cautioned that their analysis was underpowered for such a subgroup analysis, and they called for validation in larger studies.

Overall, their results add to a growing body of evidence questioning if 28-day venetoclax is indeed efficacious and tolerable. Previous research shows that among patients with newly diagnosed AML on either a 14-day treatment plan at full dose or a 21-day treatment plan at reduced dose, CR and composite remission rates and OS advantage were higher vs patients prescribed a 28-day course of treatment.⁴ This is because patients were able to stay on treatment rather than discontinue because of cytopenia-driven interruptions.

Treatment interruptions, febrile neutropenia, and hospitalizations drive significant costs and resource use in a population already vulnerable to treatment-related morbidity. Momentum is building behind azacitidine-venetoclax as a potential frontline option in younger, fit patients who might otherwise proceed to intensive chemotherapy.⁴ Overall, however, the present study authors’ conclusion is more narrow: rather than shortening venetoclax duration across the board, they think dosing may need to be tailored by mutation status, and they call for larger prospective studies to help accomplish this.

“Certain subgroups may benefit from prolonged [venetoclax] exposure,” they write, “but these findings require validation in larger studies, especially as triplet regimens evolve.”

References

1. Borate UM, Huan Y, Lin TL, et al. OPTI-AML: prospective comparison of 28 vs. 14 days of venetoclax induction with azacitidine in older adults with AML. Blood. Published online July 28, 2026. doi:10.1182/blood.2026034611
2. Di Nardo CD, Jona BA, Pullarkat V, et al. Azacitidine and venetoclax in previously untreated acute myeloid leukemia. N Engl J Med. 2020;383(7):617-629. doi:10.1056/NEJMoa2012971
3. Joszt L. Modified venetoclax dose outperforms standard care in unfit AML patients. AJMC^®. January 9, 2026. Accessed August 18, 2026. https://www.ajmc.com/view/modified-venetoclax-dose-outperforms-standard-care-in-unfit-aml-patients
4. Caffrey M. meaning a large share of the unfit AML population may tolerate a shortened venetoclax course without sacrificing remission rates, while a genomically defined subset may need the full exposure to achieve the same benefit. AJMC. December 8, 2025. Accessed August 19, 2026. https://www.ajmc.com/view/data-could-let-azacitidine-and-venetoclax-challenge-chemo-for-treatment-of-fit-patients-with-aml