Post-Remission Treatment with Chemotherapy or Allogeneic Hematopoietic Stem Cell Transplantation (alloHSCT) in Adult Patients with High-Risk (HR) Philadelphia Chromosome-Negative (Ph-neg) Acute Lymphoblastic Leukemia (ALL) According to Their Minimal Residual Disease (MRD). Final Results of the Pethema ALL-HR-11 Trial

Introduction: Recent studies have shown that young to middle-aged adults who receive a pediatric-inspired chemotherapy regimen for treatment of Ph-neg ALL do not appear to require an alloHSCT if they achieve good response on MRD testing after induction and/or consolidation therapy. Patients (pts) who are not good MRD responders achieve better outcomes with alloHSCT than their counterparts who do not receive alloHSCT. However, it is not clear if this approach can specifically apply to adult ALL pts with HR features at baseline. The aim of the prospective ALL-HR-11 trial (NCT01540812) from the Spanish PETHEMA Group was to evaluate response of HR Ph-neg adult ALL patients to a different post-induction therapy (chemotherapy or alloHSCT) according to MRD levels (centrally assessed by 8-color flow cytometry [FCM]) at the end of induction (week 5) and consolidation therapy (week 17).. Patients and methods: HR ALL included one or more of the following parameters at baseline: age 30-60y, WBC count >30x109/L for B-cell precursor ALL or >100x109/L for thymic T-ALL, pro-B, early or mature T-ALL, 11q23 or KMT2A rearrangements or complex karyotype. Induction therapy included vincristine, prednisone, daunorubicin and asparaginase (E coli native or PEG according to center availability) for 4 weeks (Induction-1). FLAG-Ida was administered as intensified induction (Induction-2) in pts not achieving CR or in those in CR with MRD≥0.1% at the end of induction. For pts in CR and MRD Results: On April 2019, 307 HR ALL pts were evaluable. Median (range) age was 40 (15-60) y, 192 were males, 211 precursor B-ALL and 96 T-ALL, with a median WBC count of 12.9 (0.2-564) x109/L. Results of Induction-1 (n=304, 3 on induction): therapy-related death: 12(4%), resistance: 39(13%), CR: 253(83%). MRD Conclusions: This trial, in which post-induction therapy was only based on MRD results assessed by FCM, suggests that avoiding alloHSCT does not hamper the outcome of HR Ph-neg adult ALL pts with adequate MRD response after induction and after consolidation. Better post-remission alternative therapies are specially needed for patients with poor MRD clearance. Supported by grants PI14/01971 FIS, Instituto Carlos III, and SGR225 (GRE), Spain. Download : Download high-res image (126KB) Download : Download full-size image Disclosures Montesinos: Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: Research support; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau. Esteve: Novartis: Consultancy, Research Funding, Speakers Bureau; Roche: Consultancy; Pfizer: Consultancy; Astellas: Consultancy, Speakers Bureau; Amgen: Consultancy; Celgene: Consultancy, Speakers Bureau; Daiichi Sankyo: Consultancy; Jazz Pharmaceuticals: Consultancy.