This report focuses on the adaptive phase I trial design aimed to find the clinically applicable dose for decitabine maintenance treatment after allogeneic hematopoietic stem cell transplantation in patients with higher-risk myelodysplastic syndrome and secondary acute myeloid leukemia. The first cohort (three patients) was given the same initial daily dose of decitabine (5 mg/m2/day, five consecutive days with 4-week intervals). In all cohorts, the doses for Cycles 2 to 4 were individualized using pharmacokinetic-pharmacodynamic modeling and simulations. The goal of dose individualization was to determine the maximum dose for each patient at which the occurrence of grade 4 (CTC-AE) toxicities for both platelet and neutrophil counts could be avoided. The initial doses for the following cohorts were also estimated with the data from the previous cohorts in the same manner. In all but one patient (14 out of 15), neutrophil count was the dose-limiting factor throughout the cycles. In cycles where doses were individualized, the median neutrophil nadir observed was 1100/mm3 (grade 2) and grade 4 toxicity occurred in 5.1 % of all cycles (while it occurred in 36.8 % where doses were not individualized). The initial doses estimated for cohorts 2 to 5 were 4, 5, 5.5, and 5 mg/m2/day, respectively. The median maintenance dose was 7 mg/m2/day. We determined the acceptable starting dose and individualized the maintenance dose for each patient, while minimizing the toxicity using the adaptive approach. Currently, 5 mg/m2/day is considered to be the most appropriate starting dose for the regimen studied. Clinicaltrials.gov NCT01277484

Background Human natural killer (NK) cell lines serve as an attractive source for adoptive immunotherapy, but NK-92 remains the only cell line being assessed in the clinic. Here, we established a novel NK cell line, NK101, from a patient with extra-nodal natural killer/T-cell lymphoma and examined its phenotypic, genomic and functional characteristics. Methods Single cell suspensions from lymphoma tissue were expanded with anti-NKp46/anti-CD2-coated beads in the presence of IL-2. A continuously growing CD56⁺ cell clone was selected and designated as NK101. Flow cytometry and RNA sequencing were used to characterize phenotypic and genomic features of NK101. In vitro cytotoxicity and IFN-γ/TNF-α secretion were measured by flow cytometry-based cytotoxicity assay and enzyme-linked immunosorbent assay, respectively, after direct co-culture with tumor cells. Immunomodulatory potential of NK101 was assessed in an indirect co-culture system using conditioned medium. Finally, in vivo antitumor efficacy was evaluated in an immunocompetent, syngeneic 4T1 mammary tumor model. Results NK101 displayed features of CD56^dimCD62L⁺ intermediate stage NK subset with the potential to simultaneously act as a cytokine producer and a cytotoxic effector. Comparative analysis of NK101 and NK-92 revealed that NK101 expressed lower levels of perforin and granzyme B that correlated with weaker cytotoxicity, but produced higher levels of pro-inflammatory cytokines including IFN-γ and TNF-α. Contrarily, NK-92 produced greater amounts of anti-inflammatory cytokines, IL-1 receptor antagonist and IL-10. Genome-wide analysis revealed that genes associated with positive regulation of leukocyte proliferation were overexpressed in NK101, while those with opposite function were highly enriched in NK-92. The consequence of such expressional and functional discrepancies was well-represented in (i) indirect co-culture system where conditioned medium derived from NK101 induced greater proliferation of human peripheral blood mononuclear cells and (ii) immunocompetent 4T1 tumor model where peritumoral injections of NK101 displayed stronger anti-tumor activities by inducing higher tumor-specific immune responses. In a manufacturing context, NK101 not only required shorter recovery time after thawing, but also exhibited faster growth profile than NK-92, yielding more than 200-fold higher cell numbers after 20-day culture. Conclusion NK101 is a unique NK cell line bearing strong immunostimulatory potential and substantial scalability, providing an attractive source for adoptive cancer immunotherapy.

PURPOSE: Pirtobrutinib, a highly selective, noncovalent Bruton tyrosine kinase inhibitor (BTKi), has shown efficacy and safety in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) who received prior covalent BTKi. We report results, to our knowledge, from the first randomized head-to-head comparison of pirtobrutinib versus ibrutinib in BTKi-naïve CLL/SLL in both treatment-naïve (TN) patients and patients with relapsed/refractory (R/R) disease. PATIENTS AND METHODS: Patients (N = 662) were randomly assigned 1:1 to receive pirtobrutinib or ibrutinib. All patients were BTKi-naïve. Primary end points were overall response rate (ORR) by independent review committee (IRC) among all randomly assigned patients (intention to treat [ITT]) and in patients with R / R disease. RESULTS: The study met its primary end points, demonstrating statistically significant noninferiority (NI) of IRC-ORR for pirtobrutinib versus ibrutinib in both the ITT (87.0% [95% CI, 82.9 to 90.4] v 78.5% [95% CI, 73.7 to 82.9]; ORR ratio = 1.11 [95% CI, 1.03 to 1.19]; two-sided P < .0001) and R/R populations (n = 437; 84.0% [95% CI, 78.5 to 88.6] v 74.8% [95% CI, 68.5 to 80.4]; ORR ratio = 1.12 [95% CI, 1.02 to 1.24]; two-sided P < .0001). In TN patients (n = 225), IRC-ORR was 92.9% (95% CI, 86.4 to 96.9) with pirtobrutinib versus 85.8% (95% CI, 78.0 to 91.7) with ibrutinib. Investigator assessed ORR results were consistent. Investigator-assessed progression-free survival (PFS) favored pirtobrutinib in the ITT (hazard ratio [HR], 0.57 [95% CI, 0.39 to 0.83]), R/R (HR, 0.73 [95% CI, 0.47 to 1.13]), and TN (HR, 0.24 [95% CI, 0.10 to 0.59]) populations. Cardiac adverse event rates of atrial fibrillation/flutter and hypertension were lower with pirtobrutinib. CONCLUSION: Pirtobrutinib demonstrated NI of ORR versus ibrutinib, with a favorable early PFS trend, particularly in TN patients, and a favorable safety profile including low rates of atrial fibrillation and hypertension.

PURPOSE: BRUIN CLL-313 is a randomized, open-label, global phase III study comparing the efficacy and safety of pirtobrutinib, a highly selective, noncovalent Bruton tyrosine kinase inhibitor (BTKi), against bendamustine plus rituximab (BendaR), a common frontline chemoimmunotherapy, in treatment-naïve patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). METHODS: Patients with previously untreated CLL/SLL without del(17p) were randomly assigned 1:1 to continuous pirtobrutinib monotherapy or BendaR, stratified by immunoglobulin heavy chain gene mutation status and Rai stage. The primary end point was independent review committee (IRC)–assessed progression-free survival (PFS); secondary end points included overall survival (OS), investigator (INV)–assessed PFS, safety, and tolerability. RESULTS: Overall, 282 patients were randomly assigned to receive pirtobrutinib (n = 141) or BendaR (n = 141). IRC-assessed PFS was significantly improved with pirtobrutinib versus BendaR (hazard ratio [HR], 0.199 [95% CI, 0.107 to 0.367]; P < .0001), and the 24-month PFS rate was 93.4% (95% CI, 87.6 to 96.5) and 70.7% (95% CI, 61.5 to 78.1), respectively. INV-assessed PFS similarly favored pirtobrutinib (HR, 0.186 [95% CI, 0.093 to 0.371]). Interim analysis of OS favored pirtobrutinib (median follow-up 32 months; HR, 0.257 [95% CI, 0.070 to 0.934]) despite an effective crossover rate of 52.9%. In patients receiving pirtobrutinib versus BendaR: adverse event (AE)–related dose reductions occurred in 3.6% versus 31.1% of patients; grade ≥3 treatment-emergent AEs (TEAEs) occurred in 40.0% versus 67.4% of patients; and treatment discontinuations because of TEAEs occurred in 4.3% versus 15.2% of patients, respectively. CONCLUSION: Pirtobrutinib demonstrated superiority over BendaR in IRC-assessed PFS in treatment-naïve CLL/SLL. OS trends favored pirtobrutinib despite the study design allowing for crossover. Pirtobrutinib was well tolerated, consistent with its known safety profile, and more favorable than BendaR.

There is growing evidence that crosstalk between mantle cell lymphoma (MCL) cells and stromal microenvironments, such as bone marrow and secondary lymphoid tissues, promotes tumor progression by enhancing survival and growth as well as drug resistance of MCL cells. Recent advances in the understanding of lymphoma microenvironment have led to the identification of crucial factors involved in the crosstalk and subsequent generation of their targeted agents. In the present study, we evaluated the combinatory effect of blocking antibodies (Ab) targeting CXCR4 and VLA-4, both of which were known to play significant roles in the induction of environment-mediated drug resistance (EMDR) in MCL cell line, Jeko-1. Simultaneous treatment with anti-CXCR4 and anti-VLA-4 Ab not only reduced the migration of Jeko-1 cells into the protective stromal cells, but also enhanced sensitivity of Jeko-1 to a chemotherapeutic agent to a greater degree than with either Ab alone. These combinatorial effects were associated with decreased phosphorylation of ERK1/2, AKT and NF-κB. Importantly, drug resistance could not be overcome once the adhesion of Jeko-1 to the stromal occurred despite the combined use of Abs, suggesting that the efforts to mitigate migration of MCLs should be attempted as much as possible. Our results provide a basis for a future development of therapeutic strategies targeting both CXCR4 and VLA-4, such as Ab combinations or bispecific antibodies, to improve treatment outcomes of MCL with grave prognosis.

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in Western countries. However, CLL is relatively rare in Asia; its genetic features are rarely studied. Here, we aimed to genetically characterize Korean CLL patients and to elucidate the genetic and clinical associations based on data obtained from 113 patients at a single Korean institute. We used next-generation sequencing to explore the multi-gene mutational data and immunoglobulin heavy chain variable gene clonality with somatic hypermutation (SHM). MYD88 (28.3%), including L265P (11.5%) and V217F (13.3%), was the most frequently mutated gene, followed by KMT2D (6.2%), NOTCH1 (5.3%), SF3B1 (5.3%), and TP53 (4.4%). MYD88-mutated CLL was characterized by SHM and atypical immunophenotype with fewer cytogenetic abnormalities. The 5-year time to treatment (TTT) of the overall cohort was 49.8% ± 8.2% (mean ± standard deviation) and the 5-year overall survival was 86.2% ± 5.8%. Patients with SHM, isolated del(13q), TP53-wild type, and NOTCH1-wild type showed better results than those without these conditions. In the subgroup analyses, patients with SHM and L265P presented shorter TTT than patients with SHM but not L265P. In contrast, V217F was associated with a higher SHM percentage and showed a favorable prognosis. Our study revealed the distinct characteristics of Korean CLL patients with high frequencies of MYD88 mutations and their clinical relevance.