The upcoming 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours is part of an effort to hierarchically catalogue human cancers arising in various organ systems within a single relational database. This paper summarizes the new WHO classification scheme for myeloid and histiocytic/dendritic neoplasms and provides an overview of the principles and rationale underpinning changes from the prior edition. The definition and diagnosis of disease types continues to be based on multiple clinicopathologic parameters, but with refinement of diagnostic criteria and emphasis on therapeutically and/or prognostically actionable biomarkers. While a genetic basis for defining diseases is sought where possible, the classification strives to keep practical worldwide applicability in perspective. The result is an enhanced, contemporary, evidence-based classification of myeloid and histiocytic/dendritic neoplasms, rooted in molecular biology and an organizational structure that permits future scalability as new discoveries continue to inexorably inform future editions.

The BCL-2 inhibitor venetoclax combined with hypomethylating agents or low-dose cytarabine represents an important new therapy for older or unfit patients with acute myeloid leukemia (AML). We analyzed 81 patients receiving these venetoclax-based combinations to identify molecular correlates of durable remission, response followed by relapse (adaptive resistance), or refractory disease (primary resistance). High response rates and durable remissions were typically associated with NPM1 or IDH2 mutations, with prolonged molecular remissions prevalent for NPM1 mutations. Primary and adaptive resistance to venetoclax-based combinations was most commonly characterized by acquisition or enrichment of clones activating signaling pathways such as FLT3 or RAS or biallelically perturbing TP53. Single-cell studies highlighted the polyclonal nature of intratumoral resistance mechanisms in some cases. Among cases that were primary refractory, we identified heterogeneous and sometimes divergent interval changes in leukemic clones within a single cycle of therapy, highlighting the dynamic and rapid occurrence of therapeutic selection in AML. In functional studies, FLT3 internal tandem duplication gain or TP53 loss conferred cross-resistance to both venetoclax and cytotoxic-based therapies. Collectively, we highlight molecular determinants of outcome with clinical relevance to patients with AML receiving venetoclax-based combination therapies.

Background: Preclinical models showed that blocking PD-1/PD-L1 pathways enhanced anti-leukemic responses. Azacitidine up-regulates PD-1 and interferon-gamma signaling. Methods: In this single arm trial, patients with relapsed/refractory (R/R) AML were treated with azacitidine 75mg/m2 Days 1–7 intravenously or subcutaneously with nivolumab 3mg/kg intravenously on Day 1 and 14, every 4–6 weeks. Findings: Seventy patients were treated. The median age was 70 years (range, 22–90). The median number of prior therapies received was 2 (range, 1–7). The overall response rate (ORR) was 33% including 15 (22%) complete remission (CR)/complete remission with insufficient recovery of counts (CRi), 1 partial response, and 7 patients with hematologic improvement (HI) maintained >6 months. Six patients (9%) had stable disease >6 months. The ORR was 58% and 22%, in HMA-naïve (n=25) and HMA pre-treated (n=45) patients, respectively. Grade 3–4 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. CTLA-4 was significantly up-regulated on CD4+Teff in non-responders after 2 and 4 doses of nivolumab. Interpretation: 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. Trial Registration ID: Clinicaltrials.gov identifier: NCT02397720

Key Points Approximately 20% to 25% of adults with B-ALL have Ph-like ALL with increased frequency of Ph-like ALL in adults with Hispanic ethnicity. Adult patients with CRLF2+ ALL have poor long-term outcomes; novel strategies are needed to improve the outcomes.

A B S T R A C T PurposeWe report the experience with 2,000 consecutive patients with advanced cancer who underwent testing on a genomic testing protocol, including the frequency of actionable alterations across tumor types, subsequent enrollment onto clinical trials, and the challenges for trial enrollment. Patients and MethodsStandardized hotspot mutation analysis was performed in 2,000 patients, using either an 11-gene (251 patients) or a 46-or 50-gene (1,749 patients) multiplex platform. Thirty-five genes were considered potentially actionable based on their potential to be targeted with approved or investigational therapies. ResultsSeven hundred eighty-nine patients (39%) had at least one mutation in potentially actionable genes. Eighty-three patients (11%) with potentially actionable mutations went on genotypematched trials targeting these alterations. Of 230 patients with PIK3CA/AKT1/PTEN/BRAF mutations that returned for therapy, 116 (50%) received a genotype-matched drug. Forty patients (17%) were treated on a genotype-selected trial requiring a mutation for eligibility, 16 (7%) were treated on a genotype-relevant trial targeting a genomic alteration without biomarker selection, and 40 (17%) received a genotype-relevant drug off trial. Challenges to trial accrual included patient preference of noninvestigational treatment or local treatment, poor performance status or other reasons for trial ineligibility, lack of trials/slots, and insurance denial. ConclusionBroad implementation of multiplex hotspot testing is feasible; however, only a small portion of patients with actionable alterations were actually enrolled onto genotype-matched trials. Increased awareness of therapeutic implications and access to novel therapeutics are needed to optimally leverage results from broad-based genomic testing.