Intensive Versus Non-Intensive Induction Therapy for Patients (Pts) with Newly Diagnosed Acute Myeloid Leukemia (AML) Using Two Different Novel Prognostic Models
Authors: Sorror Mohamed L. , Storer Barry E. , Elsawy Mahmoud , Fathi Amir T. , Brunner Andrew M. , Gerds Aaron T. , Sekeres Mikkael A. , Mukherjee Sudipto , Medeiros Bruno C. , Wang Eunice S. , Vachhani Pankit , Shami Paul J , Peña Esteban , Wardyn Shylo , Whitten Jenny , Moore Rachelle , Becker Pamela S. , McCune Jeannine , Lee Stephanie J. , Sandmaier Brenda M. , Appelbaum Frederick R. , Estey Elihu H. 
Published: October 2019

Background: Induction therapy for newly diagnosed AML pts can be classified as intensive or non-intensive. Non-intensive therapies are increasingly used in pts aged >65 years due to concerns about their ability to tolerate intensive chemotherapy. However, the relative benefit-risk ratios associated with intensive versus non-intensive therapies in AML pts is likely affected by age, comorbidities, and disease-related characteristics, such as cytogenetic and molecular features. Here, we examine these relationships.

Methods: Data from 1295 newly diagnosed AML patients, given induction therapy between 2008 and 2012 at six participating academic centers, were retrospectively collected. We used two previously validated models to define distinct prognostic groups, and within each, compared 2-year mortality rates according to whether pts received intensive or non-intensive therapy. Non-intensive therapy principally included azacitidine, decitabine, or low-dose cytarabine, while intensive therapies primarily included the standard 7+3 regimen or "high-dose" cytarabine combinations with anthracyclines or purine analogs. The first model (Blood 2015; 126:532) was a composite of the prognostic effects of age, comorbidity index, and cytogenetic/genetics risks per European Leukemia Net (ELN) classification. The second (JCO 2011; 29(33): 4417) was a treatment related mortality (TRM) index including 8 pt- and AML-specific risk factors.

Results: Age distribution of the pts were ≤49 (23%), 50-59 (20%), 60-69 (33%), and ≥70 (24%) years old. Median follow-up for currently alive pts was 41 (range, 0-99) months. Cytogenetic-molecular risks per ELN classification were favorable (18%), intermediate I and II (39%), or unfavorable (43%). Induction treatments were intensive in 77% and non-intensive in 23% of pts. The proportion of patients receiving non-intensive therapy increased with increasing age (Table 1).

Almost all pts (99%) with the lowest composite scores (1-3) received intensive therapies and were therefore omitted from the comparisons with either model. Per the composite model grouping, pts had better survival rates if they received intensive therapy, although the differences were not statistically significant in pts with composite scores ≥10 (Table 2). Pts with TRM scores of 0-4 and ≥5, with a score of 5 corresponding to the median score, statistically significantly benefitted from intensive therapies (Table 2). Among all pts aged 70-79 years old (n=242), 41% received intensive therapy, while 59% received non-intensive therapy. The intensively treated pts in this age range had statistically significantly higher survival rates at 2 years (26% versus 13%, HR: 0.73, 95% CI: 0.54-0.98, P=0.04, Figure).

Conclusion: After accounting for underlying prognosis using 2 validated models, we found pts with newly diagnosed AML generally had better survival if they received intensive therapy. This survival benefit was not statistically proven for pts with the highest composite scores (≥10). Early mortality was not increased in older pts given intensive versus non-intensive therapy (Figure), likely due to improvements in supportive care which allowed the greater anti AML effect of intensive therapy to become manifest over time. While we cannot exclude the effects of selection bias, absent a randomized trial our results suggest intensive therapy could be considered for most pts, up to the age of 80 years, regardless of their comorbidity burden. Although results seem better with intensive therapy, less than 50% of patients with composite scores >3 given such therapies were predicted to be alive at 2 years, suggesting the need for randomized clinical trials between novel intensive and non-intensive therapies to achieve better survival.

Table 1 Regimen intensity per pt age groups Table 1. Regimen intensity per pt age groups Table 2 Comparisons of hazard ratios (HR) and 2-year rates of survival between intensive and non-intensive initial therapies Table 2. Comparisons of hazard ratios (HR) and 2-year rates of survival between intensive and non-intensive initial therapies Figure. Intensive versus non-intensive therapies among pts aged 70-79 years with AML Figure. Intensive versus non-intensive therapies among pts aged 70-79 years with AML

Disclosures

Fathi: Bexalata: Other: Advisory Board participation; Celgene: Consultancy, Research Funding; Merck: Other: Advisory Board participation; Agios Pharmaceuticals: Other: Advisory Board participation; Seattle Genetics: Consultancy, Other: Advisory Board participation, Research Funding. Sekeres:Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Mukherjee:Novartis: Consultancy, Honoraria, Research Funding; Ariad: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Wang:Incyte: Speakers Bureau; Immunogen: Research Funding. Shami:JSK Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding.