Impact of CD19 CAR T-cell product type on outcomes in relapsed or refractory aggressive B-NHL.

CD19-targeted chimeric antigen receptor-engineered (CD19 CAR) T cells are novel therapies showing great promise for patients with relapsed or refractory (R/R) aggressive B-cell non-Hodgkin lymphoma (B-NHL). Single-arm studies showed significant variations in outcomes across distinct CD19 CAR T-cell products. To estimate the independent impact of the CAR T-cell product type on outcomes, we retrospectively analyzed data from 129 patients with R/R aggressive B-NHL treated with cyclophosphamide and fludarabine lymphodepletion followed by either a commercially available CD19 CAR T-cell therapy (axicabtagene ciloleucel [axicel] or tisagenlecleucel [tisacel]), or the investigational product JCAR014 on a phase 1/2 clinical trial (NCT01865617). After adjustment for age, hematopoietic cell transplantation-specific comorbidity index, lactate dehydrogenase (LDH), largest lesion diameter, and absolute lymphocyte count (ALC), CAR T-cell product type remained associated with outcomes in multivariable models. JCAR014 was independently associated with lower cytokine release syndrome (CRS) severity compared with axicel (adjusted odds ratio [aOR], 0.19; 95% confidence interval [CI]; 0.08-0.46), with a trend toward lower CRS severity with tisacel compared with axicel (aOR, 0.47; 95% CI, 0.21-1.06; P = .07). Tisacel (aOR, 0.17; 95% CI, 0.06-0.48) and JCAR014 (aOR, 0.17; 95% CI, 0.06-0.47) were both associated with lower immune effector cell-associated neurotoxicity syndrome severity compared with axicel. Lower odds of complete response (CR) were predicted with tisacel and JCAR014 compared with axicel. Although sensitivity analyses using either positron emission tomography- or computed tomography-based response criteria also suggested higher efficacy of axicel over JCAR014, the impact of tisacel vs axicel became undetermined. Higher preleukapheresis LDH, largest lesion diameter, and lower ALC were independently associated with lower odds of CR. We conclude that CD19 CAR T-cell product type independently impacts toxicity and efficacy in R/R aggressive B-NHL patients.

Small molecule binding sites on the Ras:SOS complex can be exploited for inhibition of Ras activation.

Constitutively active mutant KRas displays a reduced rate of GTP hydrolysis via both intrinsic and GTPase-activating protein-catalyzed mechanisms, resulting in the perpetual activation of Ras pathways. We describe a fragment screening campaign using X-ray crystallography that led to the discovery of three fragment binding sites on the Ras:SOS complex. The identification of tool compounds binding at each of these sites allowed exploration of two new approaches to Ras pathway inhibition by stabilizing or covalently modifying the Ras:SOS complex to prevent the reloading of Ras with GTP. Initially, we identified ligands that bound reversibly to the Ras:SOS complex in two distinct sites, but these compounds were not sufficiently potent inhibitors to validate our stabilization hypothesis. We conclude by demonstrating that covalent modification of Cys118 on Ras leads to a novel mechanism of inhibition of the SOS-mediated interaction between Ras and Raf and is effective at inhibiting the exchange of labeled GDP in both mutant (G12C and G12V) and wild type Ras.

Discovery of a potent and selective EGFR inhibitor (AZD9291) of both sensitizing and T790M resistance mutations that spares the wild type form of the receptor.

Epidermal growth factor receptor (EGFR) inhibitors have been used clinically in the treatment of non-small-cell lung cancer (NSCLC) patients harboring sensitizing (or activating) mutations for a number of years. Despite encouraging clinical efficacy with these agents, in many patients resistance develops leading to disease progression. In most cases, this resistance is in the form of the T790M mutation. In addition, EGFR wild type receptor inhibition inherent with these agents can lead to dose limiting toxicities of rash and diarrhea. We describe herein the evolution of an early, mutant selective lead to the clinical candidate AZD9291, an irreversible inhibitor of both EGFR sensitizing (EGFRm+) and T790M resistance mutations with selectivity over the wild type form of the receptor. Following observations of significant tumor inhibition in preclinical models, the clinical candidate was administered clinically to patients with T790M positive EGFR-TKI resistant NSCLC and early efficacy has been observed, accompanied by an encouraging safety profile.

Discovery of 4-{4-[(3R)-3-Methylmorpholin-4-yl]-6-[1-(methylsulfonyl)cyclopropyl]pyrimidin-2-yl}-1H-indole (AZ20): a potent and selective inhibitor of ATR protein kinase with monotherapy in vivo antitumor activity.

ATR is an attractive new anticancer drug target whose inhibitors have potential as chemo- or radiation sensitizers or as monotherapy in tumors addicted to particular DNA-repair pathways. We describe the discovery and synthesis of a series of sulfonylmorpholinopyrimidines that show potent and selective ATR inhibition. Optimization from a high quality screening hit within tight SAR space led to compound 6 (AZ20) which inhibits ATR immunoprecipitated from HeLa nuclear extracts with an IC50 of 5 nM and ATR mediated phosphorylation of Chk1 in HT29 colorectal adenocarcinoma tumor cells with an IC50 of 50 nM. Compound 6 potently inhibits the growth of LoVo colorectal adenocarcinoma tumor cells in vitro and has high free exposure in mouse following moderate oral doses. At well tolerated doses 6 leads to significant growth inhibition of LoVo xenografts grown in nude mice. Compound 6 is a useful compound to explore ATR pharmacology in vivo.

Sulfonyl-morpholino-pyrimidines: SAR and development of a novel class of selective mTOR kinase inhibitor.

High throughput screening to identify inhibitors of the mTOR kinase revealed sulfonyl-morpholino-pyrimidine 1 as an attractive start point. The compound displayed good physicochemical properties and selectivity over related kinases such as PI3Kα. Library preparation of related analogs allowed the establishment of additional SAR understanding and in particular the requirement for a key hydrogen bond donor motif at the 4-position of the phenyl ring in compounds such as indole 19. Isosteric replacement of the indole functionality led to the identification of urea compounds such as 32 that show good levels of mTOR inhibition in both enzyme and cellular assays.

Evaluation of six cytometric methods for reticulocyte enumeration and differentiation in the cat.

Six protocols utilizing three fluorescent nucleic acid dyes (thiazole orange, auramine 0, and acridine orange) were evaluated by flow cytometty for clinical utility in the analysis of feline reticulocytes. The dyes showed good to poor correlations with each other and with manual counts. Thiazole orange was the preferred stain. Thiazole orange dye showed distinct peaks corresponding to aggregate and punctate reticulocytes from specimens with marked reticulocytosis. The other dyes detected increases in reticulocyte numbers but subpopulations could not be distinguished. Standardized instrument and gate settings, applied to specimens stained with thiazole orange dye, enumerated aggregate and punctate reticulowes in low celfularity specimens that lacked distinct peaks. Percentages of these cells correlated well with manual counts, offering a simplified technique for routine laboratory use.