The Ca2+-activated protein phosphatase calcineurin induces apoptosis, but the mechanism is unknown. Calcineurin was found to dephosphorylate BAD, a pro-apoptotic member of the Bcl-2 family, thus enhancing BAD heterodimerization with Bcl-xL and promoting apoptosis. The Ca2+-induced dephosphorylation of BAD correlated with its dissociation from 14-3-3 in the cytosol and translocation to mitochondria where Bcl-xL resides. In hippocampal neurons, L-glutamate, an inducer of Ca2+ influx and calcineurin activation, triggered mitochondrial targeting of BAD and apoptosis, which were both suppressible by coexpression of a dominant-inhibitory mutant of calcineurin or pharmacological inhibitors of this phosphatase. Thus, a Ca2+-inducible mechanism for apoptosis induction operates by regulating BAD phosphorylation and localization in cells.

Purpose: This phase Ib study (NCT02179918) evaluated the safety, antitumor activity, pharmacokinetics, and pharmacodynamics of utomilumab, a fully human IgG2 mAb agonist of the T-cell costimulatory receptor 4-1BB/CD137 in combination with the humanized, PD-1-blocking IgG4 mAb pembrolizumab in patients with advanced solid tumors.Experimental Design: Utomilumab (0.45-5.0 mg/kg) and pembrolizumab (2 mg/kg) were administered intravenously every 3 weeks. Utomilumab dose escalation was conducted using the time-to-event continual reassessment method.Results: Twenty-three patients received combination treatment with no dose-limiting toxicities. Treatment-emergent adverse events were mostly grades 1 to 2, without any treatment-related discontinuations. Six patients (26.1%) had confirmed complete or partial responses. Pharmacokinetics and immunogenicity of utomilumab and pembrolizumab were similar when administered alone or in combination. A trend toward higher levels of activated memory/effector peripheral blood CD8þ T cells was observed in responders versus nonresponders.Conclusions: The safety, tolerability, and clinical activity demonstrated by utomilumab in combination with pembrolizumab support further investigation in patients with advanced solid tumors.

Caspase-associated recruitment domains (CARDs) are protein interaction domains that participate in activation or suppression of CARD-carrying members of the caspase family of apoptosis-inducing proteases. A novel CARDcontaining protein was identified that is overexpressed in some types of cancer and that binds and suppresses activation of procaspase-9, which we term TUCAN (tumor-upregulated CARD-containing antagonist of caspase nine). The CARD domain of TUCAN selectively binds itself and procaspase-9. TUCAN interferes with binding of Apaf1 to procaspase-9 and suppresses caspase activation induced by the Apaf1 activator, cytochrome c. Overexpression of TUCAN in cells by stable or transient transfection inhibits apoptosis and caspase activation induced by Apaf1/ caspase-9-dependent stimuli, including Bax, VP16, and staurosporine, but not by Apaf1/caspase-9-independent stimuli, Fas and granzyme B. High levels of endogenous TUCAN protein were detected in several tumor cell lines and in colon cancer specimens, correlating with shorter patient survival. Thus, TUCAN represents a new member of the CARD family that selectively suppresses apoptosis induced via the mitochondrial pathway for caspase activation.

Non-small cell lung cancer patients carrying oncogenic EGFR mutations initially respond to EGFR-targeted therapy, but later elicit minimal response due to dose-limiting toxicities and acquired resistance. EGF816 is a novel, irreversible mutant-selective EGFR inhibitor that specifically targets EGFR-activating mutations arising de novo and upon resistance acquisition, while sparing wild-type (WT) EGFR. EGF816 potently inhibited the most common EGFR mutations L858R, Ex19del, and T790M in vitro, which translated into strong tumor regressions in vivo in several patient-derived xenograft models. Notably, EGF816 also demonstrated antitumor activity in an exon 20 insertion mutant model. At levels above efficacious doses, EGF816 treatment led to minimal inhibition of WT EGFR and was well tolerated. In single-dose studies, EGF816 provided sustained inhibition of EGFR phosphorylation, consistent with its ability for irreversible binding. Furthermore, combined treatment with EGF816 and INC280, a cMET inhibitor, resulted in durable antitumor efficacy in a xenograft model that initially developed resistance to firstgeneration EGFR inhibitors via cMET activation. Thus, we report the first preclinical characterization of EGF816 and provide the groundwork for its current evaluation in phase I/II clinical trials in patients harboring EGFR mutations, including T790M.

BackgroundThis phase I, four-arm, open-label study (NCT01347866) evaluated the PI3K/mTOR inhibitors PF-04691502 (arms A, B) and gedatolisib (PF-05212384; arms C, D) in combination with the MEK inhibitor PD-0325901 (arm A, D) or irinotecan (arm B, C) in patients with advanced solid tumors.ObjectivesPrimary endpoint was dose-limiting toxicity with each combination. Secondary endpoints included safety, pharmacokinetics and preliminary antitumor activity.Patients and MethodsDose escalation followed a 3 + 3 design in arm C and a zone-based design in arm D.ResultsThe PF-04691502 combination arms were closed prematurely due to low tolerability, and the maximum tolerated doses (MTDs) were not determined for either arm. The MTD for the combination of gedatolisib with irinotecan 180 mg/m2 was estimated to be 110 mg weekly and for the combination with PD-0325901 was not reached at the highest dose evaluated (gedatolisib 154 mg weekly). Plasma concentrations of gedatolisib were generally similar across dose groups in arm C (with irinotecan) and arm D (with PD-0325901). Frequent dose delays or dose reductions were required for both combinations, potentially preventing sustained therapeutic drug concentrations. Gedatolisib plus irinotecan produced a response rate of ~5% and clinical benefit in 16% of patients with advanced colorectal cancer (progression-free survival, 2.8 months). Preliminary evidence of clinical activity was observed with gedatolisib plus PD-0325901 in patients with ovarian cancer (three partial responses, n = 5) or endometrial cancer (one partial response, n = 1) and KRAS mutations.ConclusionsFurther evaluations of gedatolisib are warranted in patients with advanced solid malignancies.Electronic supplementary materialThe online version of this article (10.1007/s11523-017-0530-5) contains supplementary material, which is available to authorized users.