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Supplementary Tables S1-2, Figure 1. Supplementary Table S1. Matrix view of Part A-2 dose titration and PK sampling scheme. Supplementary Table S2. Efficacy outcomes by investigator review per RECIST v1.1. Supplementary Figure 1. Seventeen patients were tested with IFN-γ ELISPOT assay.

Figure S1. Seventeen patients were tested with IFN-γ ELISPOT assay.

Purpose: The purpose of this study was to assess the association of baseline tumor size (BTS) with other baseline clinical factors and outcomes in pembrolizumab-treated patients with advanced melanoma in KEYNOTE-001 (NCT01295827).Experimental Design: BTS was quantified by adding the sum of the longest dimensions of all measurable baseline target lesions. BTS as a dichotomous and continuous variable was evaluated with other baseline factors using logistic regression for objective response rate (ORR) and Cox regression for overall survival (OS). Nominal P values with no multiplicity adjustment describe the strength of observed associations.Results: Per central review by RECIST v1.1, 583 of 655 patients had baseline measurable disease and were included in this post hoc analysis. Median BTS was 10.2 cm (range, 1–89.5). Larger median BTS was associated with Eastern Cooperative Oncology Group performance status 1, elevated lactate dehydrogenase (LDH), stage M1c disease, and liver metastases (with or without any other sites; all P ≤ 0.001). In univariate analyses, BTS below the median was associated with higher ORR (44% vs. 23%; P < 0.001) and improved OS (HR, 0.38; P < 0.001). In multivariate analyses, BTS below the median remained an independent prognostic marker of OS (P < 0.001) but not ORR. In 459 patients with available tumor programmed death ligand 1 (PD-L1) expression, BTS below the median and PD-L1–positive tumors were independently associated with higher ORR and longer OS.Conclusions: BTS is associated with many other baseline clinical factors but is also independently prognostic of survival in pembrolizumab-treated patients with advanced melanoma. Clin Cancer Res; 24(20); 4960–7. ©2018 AACR.See related commentary by Warner and Postow, p. 4915

Purpose: This phase I study evaluated the safety, maximum tolerated dose, antitumor activity, and pharmacokinetics and pharmacodynamics of pembrolizumab in patients with advanced solid tumors.Experimental Design: In a 3 + 3 dose escalation study, 10 patients received pembrolizumab 1, 3, or 10 mg/kg intravenously every 2 weeks until progression or intolerable toxicity. Seven additional patients received 10 mg/kg every 2 weeks. Thirteen patients participated in a 3-week intrapatient dose escalation (dose range, 0.005–10 mg/kg) followed by 2 or 10 mg/kg every 3 weeks. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.Results: No dose-limiting toxicities were observed. Maximum administered dose was 10 mg/kg every 2 weeks. One patient with melanoma and one with Merkel cell carcinoma experienced complete responses of 57 and 56+ weeks' duration, respectively. Three patients with melanoma experienced partial responses. Fifteen patients with various malignancies experienced stable disease. One patient died of cryptococcal infection 92 days after pembrolizumab discontinuation, following prolonged corticosteroid use for grade 2 gastritis considered drug related. Pembrolizumab exhibited pharmacokinetic characteristics typical of humanized monoclonal antibodies. Maximum serum target engagement was reached with trough levels of doses greater than or equal to 1 mg/kg every 3 weeks. Mechanism-based translational models with a focus on intratumor exposure prediction suggested robust clinical activity would be observed at doses ≥2 mg/kg every 3 weeks.Conclusions: Pembrolizumab was well tolerated and associated with durable antitumor activity in multiple solid tumors. The lowest dose with full potential for antitumor activity was 2 mg/kg every 3 weeks. Clin Cancer Res; 21(19); 4286–93. ©2015 AACR.See related commentary by van Elsas et al., p. 4251

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SARS-CoV-2 was shown to infect and persist in the human brain cells up to 230 days, highlighting the need to treat the brain viral load. The CNS disposition of antiCOVID-19 drugs: Remdesivir, Molnupiravir, and Nirmatrelvir, remains, however, unexplored. Here, we assessed the human brain pharmacokinetic profile (PK) against the EC90 values of antiCOVID-19 drugs to predict drugs with favorable brain PK against the delta and omicron variants. We also evaluated the intracellular PK of GS443902 and EIDD2061, the active metabolites of Remdesivir and Molnupiravir. Towards this, we applied LeiCNS-PK3.0, the physiologically based pharmacokinetic framework with demonstrated adequate predictions of human CNS PK. Under the recommended dosing regimens, the predicted brain extracellular fluid PK of only Nirmatrelvir was above the variants' EC90. The intracellular levels of GS443902 and EIDD2061 were below the intracellular EC90. Summarizing, our model recommends Nirmatrelvir as the promising candidate for (pre)clinical studies investigating the CNS efficacy of antiCOVID-19 drugs.

Background Very little knowledge exists on the impact of Alzheimer’s disease on the CNS target site pharmacokinetics (PK). Aim To predict the CNS PK of cognitively healthy young and elderly and of Alzheimer’s patients using the physiologically based LeiCNS-PK3.0 model. Methods LeiCNS-PK3.0 was used to predict the PK profiles in brain extracellular (brainECF) and intracellular (brainICF) fluids and cerebrospinal fluid of the subarachnoid space (CSFSAS) of donepezil, galantamine, memantine, rivastigmine, and semagacestat in young, elderly, and Alzheimer’s patients. The physiological parameters of LeiCNS-PK3.0 were adapted for aging and Alzheimer’s based on an extensive literature search. The CNS PK profiles at plateau for clinical dose regimens were related to in vitro IC50 values of acetylcholinesterase, butyrylcholinesterase, N-methyl-D-aspartate, or gamma-secretase. Results The PK profiles of all drugs differed between the CNS compartments regarding plateau levels and fluctuation. BrainECF, brainICF and CSFSAS PK profile relationships were different between the drugs. Aging and Alzheimer’s had little to no impact on CNS PK. Rivastigmine acetylcholinesterase IC50 values were not reached. Semagacestat brain PK plateau levels were below the IC50 of gamma-secretase for half of the interdose interval, unlike CSFSAS PK profiles that were consistently above IC50. Conclusion This study provides insights into the relations between CNS compartments PK profiles, including target sites. CSFSAS PK appears to be an unreliable predictor of brain PK. Also, despite extensive changes in blood-brain barrier and brain properties in Alzheimer’s, this study shows that the impact of aging and Alzheimer’s pathology on CNS distribution of the five drugs is insignificant.

Very little knowledge exists on the impact of Alzheimer's disease on the CNS target site pharmacokinetics (PK).To predict the CNS PK of cognitively healthy young and elderly and of Alzheimer's patients using the physiologically based LeiCNS-PK3.0 model.LeiCNS-PK3.0 was used to predict the PK profiles in brain extracellular (brainThe PK profiles of all drugs differed between the CNS compartments regarding plateau levels and fluctuation. Brain

Predicting brain pharmacokinetics is critical for central nervous system (CNS) drug development yet difficult due to ethical restrictions of human brain sampling. CNS pharmacokinetic (PK) profiles are often altered in CNS diseases due to disease-specific pathophysiology. We previously published a comprehensive CNS physiologically-based PK (PBPK) model that predicted the PK profiles of small drugs at brain and cerebrospinal fluid compartments. Here, we improved this model with brain non-specific binding and pH effect on drug ionization and passive transport. We refer to this improved model as Leiden CNS PBPK predictor V3.0 (LeiCNS-PK3.0). LeiCNS-PK3.0 predicted the unbound drug concentrations of brain ECF and CSF compartments in rats and humans with less than two-fold error. We then applied LeiCNS-PK3.0 to study the effect of altered cerebrospinal fluid (CSF) dynamics, CSF volume and flow, on brain extracellular fluid (ECF) pharmacokinetics. The effect of altered CSF dynamics was simulated using LeiCNS-PK3.0 for six drugs and the resulting drug exposure at brain ECF and lumbar CSF were compared. Simulation results showed that altered CSF dynamics changed the CSF PK profiles, but not the brain ECF profiles, irrespective of the drug’s physicochemical properties. Our analysis supports the notion that lumbar CSF drug concentration is not an accurate surrogate of brain ECF, particularly in CNS diseases. Systems approaches account for multiple levels of CNS complexity and are better suited to predict brain PK. Supplementary Information The online version contains supplementary material available at 10.1007/s10928-021-09768-7.

The consumption of asparagus is associated with the production of malodorous urine with considerable interindividual variability (IIV). To characterize the urinary odor kinetics after consumption of asparagus spears, we conducted a study with consenting attendees from two American Society for Clinical Pharmacology and Therapeutics (ASCPT) meetings. Subjects were randomized to eat a specific number of asparagus spears, and then asked to report their urinary odor perception. Eighty-seven subjects were included in the final analysis. A mixed effect proportional odds model was developed that adequately characterized the dose-response relationship. We estimated the half-life of the asparagus effect on malodorous urine to be 4.7 hours (relative standard error (RSE) = 13.2%), and identified a dose-response slope term with good precision (24.3%). Age was found as the predictor of IIV in slope estimates. This study design and tools can be used as a demonstration "crowdsourcing" project for studying population kinetics in organizational and educational settings.

Pembrolizumab, a potent antibody against programmed death 1 (PD-1) receptor, has shown robust antitumor activity and manageable safety in patients with advanced solid tumors. Its pharmacokinetic (PK) properties were analyzed with population PK modeling using pooled data from the KEYNOTE-001, -002, and -006 studies of patients with advanced melanoma, non-small cell lung cancer (NSCLC), and other solid tumor types. Pembrolizumab clearance was low and the volume of distribution small, as is typical for therapeutic antibodies. Identified effects of sex, baseline Eastern Cooperative Oncology Group performance status, measures of renal and hepatic function, tumor type and burden, and prior ipilimumab treatment on pembrolizumab exposure were modest and lacked clinical significance. Furthermore, simulations demonstrated the model has robust power to detect clinically relevant covariate effects on clearance. These results support the use of the approved pembrolizumab dose of 2 mg/kg every 3 weeks without dose adjustment in a variety of patient subpopulations.

Pembrolizumab, a humanized monoclonal antibody against programmed death 1 (PD-1), has a manageable safety profile and robust clinical activity against advanced malignancies. The lowest effective dose for evaluation in further dose-ranging studies was identified by developing a translational model from preclinical mouse experiments. A compartmental pharmacokinetic model was combined with a published physiologically based tissue compartment, linked to receptor occupancy as the driver of observed tumor growth inhibition. Human simulations were performed using clinical pharmacokinetic data, literature values, and in vitro parameters for drug distribution and binding. Biological and mathematical uncertainties were included in simulations to generate expectations for dose response. The results demonstrated a minimal increase in efficacy for doses higher than 2 mg/kg. The findings of the translational model were successfully applied to select 2 mg/kg as the lowest dose for dose-ranging evaluations.

Evaluation of pharmacokinetic/pharmacodynamic (PK/PD) properties played an important role in the early clinical development of pembrolizumab. Because analysis of data from a traditional 3 + 3 dose-escalation design revealed several critical uncertainties, a model-based approach was implemented to better understand these properties. Based on anticipated scenarios for potency and PK nonlinearity, a follow-up study was designed and thoroughly evaluated. Execution of 14,000 virtual trials led to the selection and implementation of a robust design that extended the low-dose range by 200-fold. Modeling of the resulting data demonstrated that pembrolizumab PKs are nonlinear at

Purpose: The purpose of this study was to assess the association of baseline tumor size (BTS) with other baseline clinical factors and outcomes in pembrolizumab-treated patients with advanced melanoma in KEYNOTE-001 (NCT01295827). Experimental Design: BTS was quantified by adding the sum of the longest dimensions of all measurable baseline target lesions. BTS as a dichotomous and continuous variable was evaluated with other baseline factors using logistic regression for objective response rate (ORR) and Cox regression for overall survival (OS). Nominal P values with no multiplicity adjustment describe the strength of observed associations. Results: Per central review by RECIST v1.1, 583 of 655 patients had baseline measurable disease and were included in this post hoc analysis. Median BTS was 10.2 cm (range, 1–89.5). Larger median BTS was associated with Eastern Cooperative Oncology Group performance status 1, elevated lactate dehydrogenase (LDH), stage M1c disease, and liver metastases (with or without any other sites; all P ≤ 0.001). In univariate analyses, BTS below the median was associated with higher ORR (44% vs. 23%; P < 0.001) and improved OS (HR, 0.38; P < 0.001). In multivariate analyses, BTS below the median remained an independent prognostic marker of OS (P < 0.001) but not ORR. In 459 patients with available tumor programmed death ligand 1 (PD-L1) expression, BTS below the median and PD-L1–positive tumors were independently associated with higher ORR and longer OS. Conclusions: BTS is associated with many other baseline clinical factors but is also independently prognostic of survival in pembrolizumab-treated patients with advanced melanoma. Clin Cancer Res; 24(20); 4960–7. ©2018 AACR. See related commentary by Warner and Postow, p. 4915

Purpose: This phase I study evaluated the safety, maximum tolerated dose, antitumor activity, and pharmacokinetics and pharmacodynamics of pembrolizumab in patients with advanced solid tumors. Experimental Design: In a 3 + 3 dose escalation study, 10 patients received pembrolizumab 1, 3, or 10 mg/kg intravenously every 2 weeks until progression or intolerable toxicity. Seven additional patients received 10 mg/kg every 2 weeks. Thirteen patients participated in a 3-week intrapatient dose escalation (dose range, 0.005–10 mg/kg) followed by 2 or 10 mg/kg every 3 weeks. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Results: No dose-limiting toxicities were observed. Maximum administered dose was 10 mg/kg every 2 weeks. One patient with melanoma and one with Merkel cell carcinoma experienced complete responses of 57 and 56+ weeks' duration, respectively. Three patients with melanoma experienced partial responses. Fifteen patients with various malignancies experienced stable disease. One patient died of cryptococcal infection 92 days after pembrolizumab discontinuation, following prolonged corticosteroid use for grade 2 gastritis considered drug related. Pembrolizumab exhibited pharmacokinetic characteristics typical of humanized monoclonal antibodies. Maximum serum target engagement was reached with trough levels of doses greater than or equal to 1 mg/kg every 3 weeks. Mechanism-based translational models with a focus on intratumor exposure prediction suggested robust clinical activity would be observed at doses ≥2 mg/kg every 3 weeks. Conclusions: Pembrolizumab was well tolerated and associated with durable antitumor activity in multiple solid tumors. The lowest dose with full potential for antitumor activity was 2 mg/kg every 3 weeks. Clin Cancer Res; 21(19); 4286–93. ©2015 AACR. See related commentary by van Elsas et al., p. 4251

Recently, immunotherapy has yielded promising results in several cancer types. Contrary to the established classical chemotherapy-dosing paradigm, a maximum tolerated dose approach does not always produce better clinical outcomes for novel targeted therapies, as their efficacy is frequently robust at pharmacologically active doses below the maximum tolerated dose. Integrated safety and efficacy assessments are needed to inform clinical dose and trial design, and to support an early identification of potentially safe and efficacious combination treatments.

The consumption of asparagus is associated with the production of malodorous urine with considerable interindividual variability (IIV). To characterize the urinary odor kinetics after consumption of asparagus spears, we conducted a study with consenting attendees from two American Society for Clinical Pharmacology and Therapeutics (ASCPT) meetings. Subjects were randomized to eat a specific number of asparagus spears, and then asked to report their urinary odor perception. Eighty‐seven subjects were included in the final analysis. A mixed effect proportional odds model was developed that adequately characterized the dose‐response relationship. We estimated the half‐life of the asparagus effect on malodorous urine to be 4.7 hours (relative standard error (RSE) = 13.2%), and identified a dose‐response slope term with good precision (24.3%). Age was found as the predictor of IIV in slope estimates. This study design and tools can be used as a demonstration “crowdsourcing” project for studying population kinetics in organizational and educational settings.

Summary Background The anti-programmed-death-receptor-1 (PD-1) antibody pembrolizumab has shown potent antitumour activity at different doses and schedules in patients with melanoma. We compared the efficacy and safety of pembrolizumab at doses of 2 mg/kg and 10 mg/kg every 3 weeks in patients with ipilimumab-refractory advanced melanoma. Methods In an open-label, international, multicentre expansion cohort of a phase 1 trial, patients (aged ≥18 years) with advanced melanoma whose disease had progressed after at least two ipilimumab doses were randomly assigned with a computer-generated allocation schedule (1:1 final ratio) to intravenous pembrolizumab at 2 mg/kg every 3 weeks or 10 mg/kg every 3 weeks until disease progression, intolerable toxicity, or consent withdrawal. Primary endpoint was overall response rate (ORR) assessed with the Response Evaluation Criteria In Solid Tumors (RECIST, version 1.1) by independent central review. Analysis was done on the full-analysis set (all treated patients with measurable disease at baseline). This study is registered with ClinicalTrials.gov, number NCT01295827. Findings 173 patients received pembrolizumab 2 mg/kg (n=89) or 10 mg/kg (n=84). Median follow-up duration was 8 months. ORR was 26% at both doses—21 of 81 patients in the 2 mg/kg group and 20 of 76 in the 10 mg/kg group (difference 0%, 95% CI −14 to 13; p=0·96). Treatment was well tolerated, with similar safety profiles in the 2 mg/kg and 10 mg/kg groups and no drug-related deaths. The most common drug-related adverse events of any grade in the 2 mg/kg and 10 mg/kg groups were fatigue (29 [33%] vs 31 [37%]), pruritus (23 [26%] vs 16 [19%]), and rash (16 [18%] vs 15 [18%]). Grade 3 fatigue, reported in five (3%) patients in the 2 mg/kg pembrolizumab group, was the only drug-related grade 3 to 4 adverse event reported in more than one patient. Interpretation The results suggest that pembrolizumab at a dose of 2 mg/kg or 10 mg/kg every 3 weeks might be an effective treatment in patients for whom there are few effective treatment options. Funding Merck Sharp and Dohme.

8022 Background: APRIL (“a proliferation-inducing ligand”) levels are elevated in the serum of patients diagnosed with multiple myeloma (MM) and is correlated to promotion of malignancy, chemo- and immune-resistance. BION-1301 (BION) is a recombinant, humanized monoclonal antibody against APRIL. We report on the initial pharmacokinetic/ pharmacodynamic (PK-PD) profile, safety, and tolerability of BION in adults with relapsed or refractory MM. Methods: Adults with MM and disease progression after ≥3 systemic therapies were recruited for the study. BION was administered every 14 days through intravenous infusion. This ongoing Phase 1/2, open-label, multicenter study is evaluating 6 cohorts with increasing BION dose levels of 50, 150, 450, 1350, and 2700 mg administered Q2W intravenously (cohort 6 - 1350 mg dose given QW and Q2W). Serum was analyzed for BION, anti-drug antibodies (ADA), and free APRIL (fAPRIL) at baseline and upon treatment, and evaluated by PK-PD modeling. Results: As of 7Dec2018 reporting through the first 4 cohorts, 15 patients were enrolled in the study (N = 3-4 per cohort). BION has been well-tolerated to date. While exposure increased dose-proportionally from 50 to 1350 mg, half-life and clearance did not significantly differ between 50 and 1350 mg. APRIL serum levels decreased with increasing BION doses. To date no DLT was observed. Non-neutralizing ADA were detected in 1 of the 15 patients. BION transiently reduced fAPRIL levels starting at a dose of 50 mg. A prolonged reduction was seen at higher doses, and at 450 mg, reduction was maintained in 2 patients on treatment for 6 cycles (5.5 months). The area under the normalized fAPRIL curve (Days 1-15) decreased 5-fold from 50 to 1350 mg. Data fit well in an exploratory PK-PD model, with kinetic binding of BION and fAPRIL according to in vitro parameters, and peripheral compartments for both entities. While at 450 mg, 95% target engagement (TG) was achieved around peak exposure levels, at 1350 mg this 95% TG was maintained throughout the dosing interval of 3 doses. Conclusions: BION dose-dependently inhibits serum levels of fAPRIL between 50 to 1350 mg dose levels. Exposure was approximately dose-linear over the dose range evaluated, with a low incidence of ADA. Promising TG was obtained at prolonged dosing of 450 mg Q2W. A favorable safety profile supports continued dose escalation and more frequent dosing regimens based on PK-PD modeling. The study is ongoing with subjects exposed to higher and/or more frequent doses anticipated to result in accelerated and sustained APRIL TG. Clinical trial information: NCT03340883.

8012 Background: BION-1301 (BION) is first in class humanized monoclonal antibody directed against a proliferation-inducing ligand (APRIL) for treatment of relapsed/refractory (R/R) multiple myeloma (MM). APRIL secreted by cells in the bone marrow (BM) niche binds to BCMA (B-Cell maturation antigen) and TACI (transmembrane activator and CAML interactor) expressed on human MM cells to drive their proliferation and survival. In patients (pts) with MM, serum APRIL levels are elevated and are correlated with promotion of malignancy, chemo- and immune-resistance. This study evaluated tolerability and clinical activity of BION monotherapy in R/R MM pts. Methods: Adults with MM, progression after ≥3 systemic therapies, and ECOG 0-1 were enrolled in this phase 1/2, open-label study. The phase 1 study is evaluating 6 cohorts with increasing BION doses of 50, 150, 450, 1350, and 2700 mg administered Q2W intravenously (cohort 6 - 1350 mg dose given QW and Q2W). Response was assessed by investigators Q4W. Serum was analyzed for BION, anti-drug antibodies (ADA), and soluble unbound “free APRIL” (fAPRIL) and evaluated by PK-PD modeling. Results: As of 7Dec2018, 15 pts were enrolled in 4 cohorts at doses between 50-1350 mg given Q2W. 5/15 (33%) had ECOG 0 and pts received median of 6 prior systemic therapies (range: 4-17). Related treatment emergent adverse events (TEAE) were reported in 8/15 (36%); most common related TEAE included anemia (n=3), arthralgia (n=2), and dysgeusia (n=2). 1 subject receiving 4th dose of BION experienced grade 3 wheezing considered infusion-related and serious. No dose-limiting toxicities were observed. Of 14/15 evaluable for response, no objective response was observed and 5/14 (36%) had stable disease. Median time on treatment was 2 months (range: 0.9-4.9+) and median of 3 doses of BION (range: 2-11) were administered. BION exposure increased dose proportionally from 50-1350 mg, and half-life (T1/2) and clearance (CL) did not differ significantly (median T1/2 = 9.0 days [range: 3.9-20], median CL = 0.52 L/day [range: 0.32-0.72]). Levels of fAPRIL in serum and BM decreased with increasing BION doses. By 450 mg, 95% target engagement (TG) was achieved around peak exposure levels. Non-neutralizing ADA was detected in 1/15 pts. Conclusions: BION, at doses 50-1350 mg given Q2W, was well-tolerated and dose-dependently reduces serum levels of fAPRIL. To date, objective responses have not been observed. The study is ongoing with pts exposed to higher and/or more frequent doses with the objective of achieving accelerated and sustained APRIL TG. Clinical trial information: NCT03340883.

APRIL critically triggers BCMA to drive proliferation and survival of human multiple myeloma (MM) cells. Importantly, APRIL induces resistance to lenalidomide, bortezomib and other standard-of-care drugs. Furthermore, APRIL drives expression of PD-L1, IL-10, VEGF and TGFβ forcing an immunosuppressive phenotype on BCMA+ cells. MM survival, resistance to treatment and the immunosuppressive phenotype can be blocked by BION-1301, the first-in class humanized antibody neutralizing APRIL. BION-1301 blocks APRIL binding to the MM relevant receptors BCMA and TACI in contrast with anti-BCMA bispecifics, ADC and CAR T-cells which use only BCMA for MM cell killing. In addition, BION-1301 inhibits immune suppressive effects of regulatory T-cells via TACI which differentiates it from BCMA targeting cytotoxic approaches. In vivo, BION-1301 was shown to suppress T cell-independent B cell responses to NP-Ficoll. Furthermore, APRIL blockade demonstrated single agent anti-MM activity in a humanized SCID model confirming its activity in vivo targeting MM cells in the tumor-protective bone marrow microenvironment. Here, we report on the preclinical pharmacokinetics (PK)/ pharmacodynamics (PD) relationship and safety analysis of BION-1301. A single-dose non-human primate (NHP) study administering intravenous BION-1301 at 0.3, 3 and 30 mg/kg, yielded PK parameters typical for IgG4 class antibodies and absence of tolerability issues. PD analysis showed a statistically significant reduction in total IgA and IgM in a dose-dependent fashion. Another measure of target modulation by BION-1301 was provided by co-injection of the hapten TNP-Ficoll (T-cell independent antigen) in different dose groups. Consistent with previous observations in hAPRIL transgenic mice, BION-1301 reduced in a dose-dependent fashion, TNP-specific IgA and IgM. Using a weekly dosing regimen, a 4-week repeat-dose toxicity study was conducted at doses of 10, 30 and 100 mg/kg, demonstrating that BION-1301 had no effect on vital organs and other toxicology related factors examined, at any dose level up to 100 mg/kg. Chronic exposure to BION-1301 led to significantly reduced levels of IgA, IgG and IgM observed at all dose levels. To determine target engagement of BION-1301, quantitative assays were developed to detect free APRIL and BION-1301. BION-1301 reduced free APRIL levels in serum in a dose-dependent manner following single and multiple dose administrations. Using a MABEL approach, PK/PD modeling informed a proposed human starting dose of 50 mg. In summary, BION-1301 showed no toxicity in NHP and binding of APRIL resulted in decreased IgA, IgG and IgM levels. PK and target engagement biomarkers predict the first in human dose using PK/PD pharmacometric modeling. A first-in-human study is ongoing to characterize safety and PK/PD of BION-1301 in heavily pretreated MM patients. Citation Format: John Dulos, Lilian Driessen, Peter van Zandvoort, Jos van de Crommert, Nitya Nair, Britta Randlev, Eduard de Cock, Jeroen Elassaiss Schaap, Hans van Eenennaam, Andrea van Elsas. Preclinical pharmacokinetics, pharmacodynamics and safety of BION-1301, a first-in-class antibody targeting APRIL for the treatment of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3780.

A b s t r ac t Background The programmed death 1 (PD-1) receptor is a negative regulator of T-cell effector mechanisms that limits immune responses against cancer. We tested the anti–PD-1 antibody lambrolizumab (previously known as MK-3475) in patients with advanced melanoma. Methods We administered lambrolizumab intravenously at a dose of 10 mg per kilogram of body weight every 2 or 3 weeks or 2 mg per kilogram every 3 weeks in patients with advanced melanoma, both those who had received prior treatment with the immune checkpoint inhibitor ipilimumab and those who had not. Tumor responses were assessed every 12 weeks. Results A total of 135 patients with advanced melanoma were treated. Common adverse events attributed to treatment were fatigue, rash, pruritus, and diarrhea; most of the adverse events were low grade. The confirmed response rate across all dose cohorts, evaluated by central radiologic review according to the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, was 38% (95% confidence interval [CI], 25 to 44), with the highest confirmed response rate observed in the cohort that received 10 mg per kilogram every 2 weeks (52%; 95% CI, 38 to 66). The response rate did not differ significantly between patients who had received prior ipilimumab treatment and those who had not (confirmed response rate, 38% [95% CI, 23 to 55] and 37% [95% CI, 26 to 49], respectively). Responses were durable in the majority of patients (median follow-up, 11 months among patients who had a response); 81% of the patients who had a response (42 of 52) were still receiving treatment at the time of analysis in March 2013. The overall median progression-free survival among the 135 patients was longer than 7 months. Conclusions In patients with advanced melanoma, including those who had had disease progression while they had been receiving ipilimumab, treatment with lambrolizumab resulted in a high rate of sustained tumor regression, with mainly grade 1 or 2 toxic effects. (Funded by Merck Sharp and Dohme; ClinicalTrials.gov number, NCT01295827.)

ObjectiveGlucocorticoids (GCs), such as prednisolone, are associated with adverse metabolic effects, including glucose intolerance and diabetes. In contrast to the well known GC-induced insulin resistance, the effects of GCs on β-cell function are less well established. We assessed the acute and short-term effects of prednisolone treatment on β-cell function in healthy men.Research design and methodsA randomised, double-blind, placebo-controlled trial consisting of two protocols was conducted. In protocol 1 (n=6), placebo and a single dose of 75 mg of prednisolone were administered. In protocol 2 (n=23), participants received 30 mg of prednisolone daily or placebo for 15 days. Both empirical and model-based parameters of β-cell function were calculated from glucose, insulin and C-peptide concentrations obtained during standardised meal tests before and during prednisolone treatment (protocols 1 and 2), and 1 day after cessation of treatment (protocol 2).ResultsSeventy-five milligrams of prednisolone acutely increased the area under the postprandial glucose curve (AUCgluc;P=0.005), and inhibited several parameters of β-cell function, including AUCc-pep/AUCglucratio (P=0.004), insulinogenic index (P=0.007), glucose sensitivity (P=0.02) and potentiation factor ratio (PFR;P=0.04). A 15-day treatment with prednisolone increased AUCgluc(PP=0.05). β-cell function parameters were impaired, including the fasting insulin secretory tone (P=0.02) and PFR (P=0.007).ConclusionsAcute and short-term exposure to prednisolone impairs different aspects of β-cell function, which contribute to its diabetogenic effects.

3068 Background: Optimization of antibody dosing in oncology drug development is an area of growing interest. We have previously demonstrated that the dose and schedule of pembrolizumab does not co...

3015 Background: We explored baseline tumor size (BTS) as a prognostic factor in addition to standard prognostic variables for overall survival (OS) in pts with metastatic melanoma treated with MK-...