Ultrasensitive NGS MRD assessment in Ph+ ALL: Prognostic impact and correlation with RT-PCR for BCR::ABL1.

Reverse transcription polymerase chain reaction (RT-PCR) for BCR::ABL1 is the most common and widely accepted method of measurable residual disease (MRD) assessment in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL); however, RT-PCR may not be an optimal measure of MRD in many cases of Ph+ ALL. We evaluated the clinical impact of a highly sensitive next-generation sequencing (NGS) MRD assay (sensitivity of 10-6 ) and its correlation with RT-PCR for BCR::ABL1 in patients with Ph+ ALL. Overall, 32% of patients had a discordance between MRD assessment by RT-PCR and NGS, and 31% of patients who achieved NGS MRD negativity were PCR+ at the same timepoint. Among eight patients with long-term detectable BCR::ABL1 by PCR, six were PCR+/NGS-. These patients generally had stable PCR levels that persisted despite therapeutic interventions, and none subsequently relapsed; in contrast, patients who were PCR+/NGS+ had more variable PCR values that responded to therapeutic intervention. In a separate cohort of prospectively collected clinical samples, 11 of 65 patients (17%) with Ph+ ALL who achieved NGS MRD negativity had detectable BCR::ABL1 by PCR, and none of these patients relapsed. Relapse-free survival and overall survival were similar in patients who were PCR+/NGS- and PCR-/NGS-, suggesting that PCR for BCR::ABL1 did not provide additional prognostic information in patients who achieved NGS MRD negativity. NGS-based assessment of MRD is prognostic in Ph+ ALL and identifies patients with low-level detectable BCR::ABL1 who are unlikely to relapse nor to benefit from therapeutic interventions.

The distribution of T-cell subsets and the expression of immune checkpoint receptors and ligands in patients with newly diagnosed and relapsed acute myeloid leukemia.

BACKGROUND: Phenotypic characterization of immune cells in the bone marrow (BM) of patients with acute myeloid leukemia (AML) is lacking. METHODS: T-cell infiltration was quantified on BM biopsies from 13 patients with AML, and flow cytometry was performed on BM aspirates (BMAs) from 107 patients with AML who received treatment at The University of Texas MD Anderson Cancer Center. The authors evaluated the expression of inhibitory receptors (programmed cell death protein 1 [PD1], cytotoxic T-lymphocyte antigen 4 [CTLA4], lymphocyte-activation gene 3 [LAG3], T-cell immunoglobulin and mucin-domain containing-3 [TIM3]) and stimulatory receptors (glucocorticoid-induced tumor necrosis factor receptor-related protein [GITR], OX40, 41BB [a type 2 transmembrane glycoprotein receptor], inducible T-cell costimulatory [ICOS]) on T-cell subsets and the expression of their ligands (41BBL, B7-1, B7-2, ICOSL, PD-L1, PD-L2, and OX40L) on AML blasts. Expression of these markers was correlated with patient age, karyotype, baseline next-generation sequencing for 28 myeloid-associated genes (including P53), and DNA methylation proteins (DNA methyltransferase 3α, isocitrate dehydrogenase 1[IDH1], IDH2, Tet methylcytosine dioxygenase 2 [TET2], and Fms-related tyrosine kinase 3 [FLT3]). RESULTS: On histochemistry evaluation, the T-cell population in BM appeared to be preserved in patients who had AML compared with healthy donors. The proportion of T-regulatory cells (Tregs) in BMAs was higher in patients with AML than in healthy donors. PD1-positive/OX40-positive T cells were more frequent in AML BMAs, and a higher frequency of PD1-positive/cluster of differentiation 8 (CD8)-positive T cells coexpressed TIM3 or LAG3. PD1-positive/CD8-positive T cells were more frequent in BMAs from patients who had multiply relapsed AML than in BMAs from those who had first relapsed or newly diagnosed AML. Blasts in BMAs from patients who had TP53-mutated AML were more frequently positive for PD-L1. CONCLUSIONS: The preserved T-cell population, the increased frequency of regulatory T cells, and the expression of targetable immune receptors in AML BMAs suggest a role for T-cell-harnessing therapies in AML.

High-sensitivity next-generation sequencing MRD assessment in ALL identifies patients at very low risk of relapse.

Measurable residual disease (MRD) is highly prognostic for relapse and overall survival (OS) in acute lymphoblastic leukemia (ALL), although many patients with apparent "MRD negativity" by standard assays still relapse. We evaluated the clinical impact of a highly sensitive next-generation sequencing (NGS) MRD assay in 74 adults with ALL undergoing frontline therapy. Among remission samples that were MRD negative by multiparameter flow cytometry (MFC), 46% were MRD+ by the NGS assay. After 1 cycle of induction chemotherapy, MRD negativity by MFC at a sensitivity of 1 × 10-4 and NGS at a sensitivity of 1 × 10-6 was achieved in 66% and 23% of patients, respectively. The 5-year cumulative incidence of relapse (CIR) among patients who achieved MRD negativity by MFC at complete remission (CR) was 29%; in contrast, no patients who achieved early MRD negativity by NGS relapsed, and their 5-year OS was 90%. NGS MRD negativity at CR was associated with significantly decreased risk of relapse compared with MRD positivity (5-year CIR, 0% vs 45%, respectively; P = .04). Among patients who were MRD negative by MFC, detection of low levels of MRD by NGS identified patients who still had a significant risk of relapse (5-year CIR, 39%). Early assessment of MRD using a highly sensitive NGS assay adds clinically relevant prognostic information to standard MFC-based approaches and can identify patients with ALL undergoing frontline therapy who have a very low risk of relapse and excellent long-term survival.

Idarubicin, cytarabine, and nivolumab in patients with newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome: a single-arm, phase 2 study.

BACKGROUND: Outcomes for younger patients with acute myeloid leukaemia have moderately improved over the past two decades owing to better supportive care and recent introduction of novel targeted agents. Blocking PD-1 and its ligand's pathways enhances antileukaemia responses by enabling T cells in murine models. We aimed to assess the addition of nivolumab to frontline therapy with idarubicin and cytarabine in patients with newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome. METHODS: This single-arm, phase 2 part of the phase 1-2 study of nivolumab in combination with idarubicin and cytarabine was done at the University of Texas MD Anderson Cancer Center (Houston, TX, USA). Eligible patients were aged 18-60 years (or >60 years if suitable for intensive chemotherapy), and had newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome, and an Eastern Cooperative Oncology Group performance status of 0-2. Induction included cytarabine 1·5 g/m2 by 24-h continuous infusion daily on days 1-4 (3 days in patients >60 years) and idarubicin 12 mg/m2 daily on days 1-3. Nivolumab 3 mg/kg was started on day 24 (range 22-26) and continued every 2 weeks for up to a year in responders. Responders received either up to five consolidation cycles of attenuated doses of idarubicin and cytarabine, or allogeneic stem cell transplantation if eligible. The primary endpoint was event-free survival. Efficacy and safety analyses were done in all patients who received at least one dose of study treatment. Secondary endpoints were relapse-free survival and overall survival. This ongoing trial is registered with ClinicalTrials.gov, number NCT02464657. FINDINGS: Between Aug 7, 2015, and June 2, 2018, 44 patients were enrolled of whom 22 (50%) had adverse genetic risk by European Leukaemia Network classification. All patients were evaluable for safety and efficacy. At a median follow-up of 17·25 months (IQR 0·50-30·40), median event-free survival was not reached (95% CI 7·93-NR). Median relapse-free survival of responders was 18·54 months (95% CI 8·20-23·22). The median overall survival was 18·54 months (95% CI 10·81-28·81). Six patients had seven grade 3-4 immune-related adverse events with two cases of rash, two of colitis, and one each of transaminitis, pancreatitis, and cholecystitis. 19 (43%) of 44 patients achieved a response and proceeded to allogeneic stem cell transplantation, with grade 3-4 graft-versus-host disease observed in five (26%). No treatment related deaths were attributed to nivolumab. INTERPRETATION: Addition of nivolumab to induction chemotherapy with idarubicin and cytarabine is feasible in patients with newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome. Post-transplant severe graft-versus-host disease could be improved, and earlier initiation of checkpoint inhibitor therapy is warranted in future studies. FUNDING: The MD Anderson Cancer Center Support Grant CA016672, and the MD Anderson Cancer Center Leukaemia SPORE CA100632 from the National Cancer Institute, Bristol Myers Squibb.

Efficacy, Safety, and Biomarkers of Response to Azacitidine and Nivolumab in Relapsed/Refractory Acute Myeloid Leukemia: A Nonrandomized, Open-Label, Phase II Study.

Preclinical models have shown that blocking PD-1/PD-L1 pathways enhances antileukemic responses. Azacitidine upregulates PD-1 and IFNγ signaling. We therefore conducted this single-arm trial, in which patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) were treated with azacitidine 75 mg/m2 days 1 to 7 intravenously or subcutaneously with nivolumab 3 mg/kg intravenously on days 1 and 14, every 4 to 6 weeks. For the seventy patients who were treated, the median age was 70 years (range, 22-90) and the median number of prior therapies received was 2 (range, 1-7). The overall response rate (ORR) was 33%, including 15 (22%) complete remission/complete remission with insufficient recovery of counts, 1 partial response, and 7 patients with hematologic improvement maintained >6 months. Six patients (9%) had stable disease >6 months. The ORR was 58% and 22%, in hypomethylating agent (HMA)-naïve (n = 25) and HMA-pretreated (n = 45) patients, respectively. Grade 3 to 4 immune-related adverse events occurred in 8 (11%) patients. Pretherapy bone marrow and peripheral blood CD3 and CD8 were significantly predictive for response on flow cytometry. CTLA4 was significantly upregulated on CD4+ Teff in nonresponders after 2 and 4 doses of nivolumab. Azacitidine and nivolumab therapy produced an encouraging response rate and overall survival in patients with R/R AML, particularly in HMA-naïve and salvage 1 patients. Pretherapy bone marrow aspirate and peripheral blood CD3 percentage may be biomarkers for patient selection. SIGNIFICANCE: Azacitidine in combination with nivolumab appeared to be a safe and effective therapy in patients with AML who were salvage 1, prior hypomethylator-naïve, or had increased pretherapy CD3+ bone marrow infiltrate by flow cytometry or IHC. Bone marrow CD3 and CD8 are relatively simple assays that should be incorporated to select patients in future trials. This article is highlighted in the In This Issue feature, p. 305.