Impulsivity is a heterogeneous construct according to clinical and preclinical behavioural measures and there is some preliminary evidence indicating distinct neurobiological substrates underlying the sub-components of impulsivity. Two preclinical assays, the five-choice serial reaction time task (5-CSRTT) and the delayed discounting task (DDT), are hypothesized to provide measures of impulsive action (premature responding) and impulsive choice (percent choice for delayed reward), respectively. In the present studies, we show that the norepinephrine reuptake inhibitor atomoxetine attenuated premature responding in the 5-CSRTT, but was ineffective in the DDT. The mixed dopamine/norepinephrine reuptake inhibitor methylphenidate exhibited an opposite profile of effects. In addition, blockade of 5-HT2A/C receptors via ketanserin decreased premature responding but had no effects on percent choice for delayed reward; blockade of 5-HT2C receptors via SB 242084 had opposite effects. Follow-up studies provided some limited evidence of additive effects of 5-HT2A/C receptor blockade on the effects of atomoxetine on impulsive action. These studies demonstrate dissociable profiles of stimulant vs. non-stimulant attention deficit hyperactivity disorder medications and 5-HT subtype-selective ligands, in the 5-CSRTT and DDT assays. Thus, the present findings support the sub-categorization of impulsivity and suggest that 5-HT receptor subtype-selective antagonists may provide therapeutic targets for disorders characterized by different forms of impulsivity.
2568 Background: IL-2 and IL-15 signal through the shared IL-2/15 βγ receptor, but unlike IL-2, IL-15 does not expand regulatory T cells (Tregs), does not mediate activation-induced cell death and may have an improved therapeutic index. KD033 is a fusion antibody combining a fully human, high affinity anti-human Programmed Death Ligand 1 (PD-L1) IgG1 antibody with the human IL-15 receptor alpha (IL15Rα) sushi domain and human IL-15 (IL-15). KD033 (or its mouse cross reactive surrogate molecule, srKD033) has been extensively characterized in multiple in vitro and in vivo nonclinical studies. The fusion of anti-PD-L1 antibody to IL-15 significantly increases the maximal-tolerated dose (MTD) of srKD033 in mice compared to free IL-15. In addition, srKD033 has exhibited increased efficacy in rejecting tumors in mice as compared to the combination of its individual components, anti-PD-L1 antibody and IL-15. Methods: This is a phase 1, open-label, multiple ascending dose, multi-center clinical trial being conducted in patients with metastatic or locally advanced solid tumors (NCT04242147). The primary objective is to determine the safety and tolerability and the MTD of KD033. Secondary objectives include characterization of PK and immunogenicity, evaluation of CD8 T and NK cell activation and assessment of best overall response and duration of response. KD033 is administered by IV infusion over 30 minutes every 14 days. Accelerated intra-patient dose escalation across the initial three dose levels, followed by 3+3 escalation thereafter, is investigating dose ranges from 3 µg/kg to 600 µg/kg. Efficacy evaluation is planned in an expansion cohort of patients with PD-1/L1 refractory tumors. Results: A total of 7 patients have received treatment. Three patients were dosed in Cohort 1 and four patients were dosed in Cohort 2. Through two dose escalation cohorts (3 µg/kg – 25 µg/kg), no dose-limiting toxicities have been reported. Grade 1-2 treatment-related toxicities, when observed, resolved within 24 hours with supportive management. 6 patients are evaluable for treatment response with one patient (adenoid cystic carcinoma) in the first cohort having stable disease for more than 6 months. Conclusions: KD033 has been well tolerated early in dose escalation with on-mechanism pharmacodynamics consistent with IL-15 agonism. Clinical trial information: NCT04242147.
BackgroundWhile IL-2 and IL-15 signal through the shared IL-2/15 βγ receptor, IL-15 does not directly expand regulatory T cells (Tregs)or mediate activation-induced cell death and may have an improved therapeutic index. KD033 is a fusion antibody combining a fully human, high affinity anti-human Programmed Death Ligand 1 (PD-L1) IgG1 antibody with the human IL-15 receptor alpha (IL15Rα) sushi domain and human IL-15 (IL-15). KD033 and its mouse cross-reactive surrogate molecule, srKD033, have been extensively characterized in multiple in vitro and in vivo nonclinical studies and have demonstrated robust efficacy and therapeutic benefits compared to IL-15 alone.MethodsThis is a phase 1, open-label, multiple ascending dose, multi-center clinical trial being conducted in patients with metastatic or locally advanced solid tumors (NCT04242147). The primary objective is to determine the safety, tolerability, and MTD of KD033. Secondary objectives include characterization of PK and immunogenicity, evaluation of CD8+ T and NK cell activation, and assessment of best overall response and duration of response. KD033 is administered by IV infusion over 30 minutes every 14 days. The study design follows 3+3 escalation investigating dose ranges from 3µg/kg to 600µg/kg.ResultsA total of 12 patients have received treatment. Three patients were dosed in Cohort 1 (C1), four patients were dosed in Cohort 2 (C2), and three patients were dosed in Cohort 3 (C3). Two patients in Cohort 4 (C4) have been dosed. Through three dose escalation cohorts (3 µg/kg – 50 µg/kg), no dose-limiting toxicities have been reported. Grade 1–2 treatment-related toxicities resolved within 24 hours with supportive management. Grade 4 decreases in lymphocytes were noted the day after dosing in C3 and C4, which resolved on day 3 and were expected. One patient (adenoid cystic carcinoma) in C1 was shown to have stable disease for more than 6 months and one patient (metastatic gastric adenocarcinoma) in C3 was shown to have stable disease for more than 4 months.ConclusionsTo date, KD033 has been well tolerated in all subjects with on-mechanism pharmacodynamics consistent with IL-15 agonism.Ethics ApprovalThis study obtained ethics approval from WIRB.
Background: IL-2 and IL-15 signal through the shared IL-2/15 βγ receptor, but unlike IL-2, IL-15 does not expand regulatory T cells (Tregs). In addition, unlike IL-2, IL-15 does not mediate activation-induced cell death and is expected to have an improved therapeutic index compared to IL-2. KD033 is a fusion antibody molecule generated by combining a fully human, high affinity anti-human Programmed Death Ligand 1 (PD-L1) IgG1 antibody with the human IL-15 receptor alpha (IL15Rα) sushi domain and human IL-15 (IL-15). KD033 (or its mouse cross reactive surrogate molecule, srKD033) has been extensively characterized in multiple in vitro and in vivo nonclinical studies to understand the pharmacology, pharmacokinetic (PK) and toxicology properties. The fusion of anti-PD-L1 antibody to IL-15 significantly increases the maximal-tolerated dose (MTD) of srKD033 in mice compared to free-IL-15. The increased safety and efficacy of PD-L1-targeted IL-15 observed in pre-clinical studies warranted evaluation of KD033 in humans. Methods: This is a phase 1, open-label, multiple ascending dose, multi-center clinical trial being conducted in patients with metastatic or locally advanced solid tumors (NCT04242147). The primary objective is to determine the safety and tolerability and the MTD of KD033. KD033 is administered as an IV infusion over 30 minutes every 14 days (i.e., a cycle equals 2 weeks). The starting dose of KD033 is 3 µg/kg, with step-up dosing to 12.5 µg/kg in the first cohort of 3 subjects. After the first cohort, the dose escalation will use a standard 3+3 design with planned doses from 25 µg/kg to 600 µg/kg. The dose escalation phase will be followed by one expansion cohort, which will enroll patients who received PD-1/PD-L1 inhibitor but have either progressed or are refractory to therapy. Secondary objectives include characterization of PK and immunogenicity, evaluation of immune correlates that will potentially differentiate the impact of KD033 versus monotherapy as well as investigate IL-15 biology and determine best overall response and duration of response. (NCT04242147) Citation Format: Jason J. Luke, Anthony J. Olszanski, Igor Puzanov, Dan Lu, Adrian Hackett, Stella Martomo, Jeegar Patel, Olivier Schueller, Alessandro Mora, Miranda L. Schlitt, Linghui Li. A phase 1 multiple ascending dose study to investigate the safety, pharmacokinetics, pharmacodynamics and preliminary efficacy of KD033 in subjects with metastatic or locally advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT227.
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