To explore the role of clonal hematopoiesis (CH) on chimeric antigen receptor (CAR) T therapy outcomes, we performed targeted deep-sequencing on buffy coats collected during the 21 days before lymphodepleting chemotherapy from 114 large B-cell lymphoma patients treated with anti-CD19 CAR T cells. We detected CH in 42 (36.8%) pre-treatment samples, most frequently in PPM1D (19/114) and TP53 (13/114) genes. Grade {greater than or equal to}3 immune-effector cell-associated neurotoxicity syndrome (ICANS) incidence was higher in CH-positive patients than CH-negative patients (45.2% vs. 25.0%, p=0.038). Higher toxicities with CH were primarily associated with DNMT3A, TET2 and ASXL1 genes (DTA mutations). Grade {greater than or equal to}3 ICANS (58.9% vs. 25%, p=0.02) and {greater than or equal to}3 cytokine release syndrome (17.7% vs. 4.2%, p=0.08) incidences were higher in DTA-positive than CH-negative patients. The estimated 24-month cumulative incidence of therapy-related myeloid neoplasms after CAR T therapy was higher in CH-positive than CH-negative patients (19% [95%CI: 5.5-38.7] vs. 4.2% [95%CI: 0.3-18.4], p=0.028).

Lenalidomide is clinically active in chronic lymphocytic leukemia (CLL), but its effectiveness in the context of the CLL mutational landscape is unknown. We performed targeted capture sequencing of 295 cancer genes in specimens from 102 CLL patients with treatment-naïve disease (TN patients) and 186 CLL patients with relapsed/refractory disease (R/R patients) who received lenalidomide-based therapy at our institution. The most frequently mutated gene was (15%), followed by (14%) and (14%), with R/R patients having significantly more mutations than did TN patients. Among all lenalidomide-treated patients, del(17p) ( ≤ .001), del(11q) ( = .032), and complex karyotype ( = .022), along with mutations in ( ≤ .001), ( = .034), and ( ≤ .001), were associated with worse overall response (OR). R/R patients with and mutations had significantly worse OR ( = .025 and .035, respectively). TN and R/R patients with del(17p) and mutations had worse overall survival (OS) and progression-free survival (PFS). In R/R patients, complex karyotype and mutations were associated with worse OS and PFS; mutations were associated with worse PFS only. Weibull regression multivariate analysis revealed that aberrations (del(17p), mutation, or both), along with complex karyotype and mutations, were associated with worse OS in the R/R cohort. Taken together, cancer gene mutations in CLL contribute to the already comprehensive risk stratification and add to prognosis and response to treatment. The related trials were registered at www.clinicaltrials.gov as #NCT00267059, #NCT00535873, #NCT00759603, #NCT01446133, and #NCT01002755.

Background Canonical Janus kinase 2 (JAK2) V617F and exon 12 mutations in myeloid neoplasms are well described. There are limited reports of other JAK2 variants of potential clinical relevance. This study was designed to survey JAK2 variants in patients with myeloproliferative neoplasms (MPNs) and acute myeloid leukemia (AML) and to determine their contributions to disease pathogenesis. Methods Next‐generation sequencing of the coding region of JAK2 and 27 other genes was performed on bone marrow DNA samples. The study population was classified into 3 cohorts: chronic MPNs only (the MPN cohort); MPNs transformed into AML (the MPN>>AML cohort); and AML only, with MPN>>AML patients excluded (the AML cohort). Results Testing was performed for 2154 patients, and non‐V617F/non–exon 12 JAK2 sequence variants were identified in 114 (5.3%). They included 35 unique JAK2 variants across all functional domains. Sixteen of the 114 JAK2 variants occurred without somatic mutations in the remaining 27 genes. JAK2 variants were detected at a higher frequency in the MPN>>AML cohort (15.3%) in comparison with the MPN (4.6%; P < .001) and AML cohorts (5.2%; P < .001). Detected variants occurred at higher than expected frequencies in patients with MPNs and AML in comparison with the population, and N1108S had a significantly increased prevalence in patients with AML. A JAK2 variant in addition to JAK2 V617F (n = 13) in myelofibrosis was associated with an increased cumulative risk of transformation into AML (P = .003). Conclusions Specific JAK2 variants detected in MPNs may be predictors for transformation into AML.

Circulating cell-free DNA (ccfDNA) allows for noninvasive peripheral blood sampling of cancer-associated mutations and has established clinical utility in several solid tumors. We performed targeted next-generation sequencing of ccfDNA and bone marrow at the time of diagnosis and after achieving remission in 22 patients with acute myeloid leukemia (AML). Among 28 genes sequenced by both platforms, a total of 39 unique somatic mutations were detected. Five mutations (13%) were detected only in ccfDNA, and 15 (38%) were detected only in bone marrow. Among the 19 mutations detected in both sources, the concordance of variant allelic frequency (VAF) assessment by both methods was high (R2 = 0.849). Mutations detected in only 1 source generally had lower VAF than those detected in both sources, suggesting that either method may miss small subclonal populations. In 3 patients, sequencing of ccfDNA detected new or persistent leukemia-associated mutations during remission that appeared to herald overt relapse. Overall, this study demonstrates that sequencing of ccfDNA in patients with AML can identify clinically relevant mutations not detected in the bone marrow and may play a role in the assessment of measurable residual disease. However, mutations were missed by both ccfDNA and bone marrow analyses, particularly when the VAF was &lt;10%, suggesting that ccfDNA and bone marrow may be complementary in the assessment and monitoring of patients with AML.

No abstract