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PDF file - 45K, Summary of adverse events suspected to be study-drug related by grade (safety set).

PDF file - 67K, Bayesian logistic regression model: dose-response curve and model inference results at the time of determination of the recommended Phase II dose.

PDF file - 65K, Criteria for defining dose-limiting toxicities.

Purpose: Phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway activation in patients with HER2-positive (HER2+) breast cancer has been implicated in de novo and acquired trastuzumab resistance. The purpose of this study was to determine the clinical activity of the PI3K inhibitor buparlisib (BKM120) in patients with HER2+ advanced/metastatic breast cancer resistant to trastuzumab-based therapy.Experimental Design: In the dose-escalation portion of this phase I/II study, patients with trastuzumab-resistant locally advanced or metastatic HER2+ breast cancer were treated with daily oral doses of buparlisib and weekly intravenous trastuzumab (2 mg/kg). Dose escalation was guided by a Bayesian logistic regression model with overdose control.Results: Of 18 enrolled patients, 17 received buparlisib. One dose-limiting toxicity of grade 3 general weakness was reported at the 100-mg/day dose level (the single-agent maximum tolerated dose) and this dose level was declared the recommended phase II dose (RP2D) of buparlisib in combination with trastuzumab. Common (>25%) adverse events included rash (39%), hyperglycemia (33%), and diarrhea (28%). The pharmacokinetic profile of buparlisib was not affected by its combination with trastuzumab. At the RP2D, there were two (17%) partial responses, 7 (58%) patients had stable disease (≥6 weeks), and the disease control rate was 75%. Pharmacodynamic studies showed inhibition of the PI3K/AKT/mTOR and RAS/MEK/ERK pathways.Conclusions: In this patient population, the combination of buparlisib and trastuzumab was well tolerated, and preliminary signs of clinical activity were observed. The phase II portion of this study will further explore the safety and efficacy of this combination at the RP2D. Clin Cancer Res; 20(7); 1935–45. ©2014 AACR.

PDF file - 38K, Patient disposition (full analysis set).

PDF file - 48K, Exposure to buparlisib and trastuzumab (safety set).

PDF file - 62K, Summary of buparlisib pharmacokinetic parameters.

Baloxavir marboxil, the prodrug of baloxavir acid, is an anti-influenza antiviral. Here, a pharmacokinetics-time to alleviation of symptoms (PK-TTAS) model was developed and used to (I) characterize the PK-TTAS relationship, (II) quantify the impact of covariates, and (III) predict TTAS in different ethnic groups. Data from 1781 otherwise-healthy (OwH) or high-risk (HR) patients included in phase II (JapicCTI-153090) and III studies (NCT02954354 and NCT02949011) were used; patients received either placebo or oral baloxavir marboxil. The natural distribution of TTAS in placebo-treated patients was modeled, then TTAS data from the baloxavir marboxil arms were added to model the impact of baloxavir acid concentration on TTAS. PK parameters estimated by a population PK model and informed by phase I data (NCT03959332 and KCT0003535) were included to simulate TTAS in Chinese and South Korean patients. Composite symptom score at baseline (TSS0), ethnicity, sex, and patient type (OwH or HR) significantly impacted the natural TTAS distribution. TTAS reduced with increasing baloxavir acid concentrations. Compared with placebo, high and low baloxavir acid exposures (AUC

Baloxavir marboxil, a prodrug of cap-dependent endonuclease inhibitor baloxavir acid, reduces the time to improvement of influenza symptoms in patients infected with type A or B influenza virus. To characterize its pharmacokinetics, a population pharmacokinetic model for baloxavir acid was developed using 11,846 plasma concentration data items from 1,827 subjects, including 2,341 plasma concentration data items from 664 patients at high risk of influenza complications. A three-compartment model with first-order elimination and first-order absorption with lag time well described the plasma concentration data., Baloxavir marboxil, a prodrug of cap-dependent endonuclease inhibitor baloxavir acid, reduces the time to improvement of influenza symptoms in patients infected with type A or B influenza virus. To characterize its pharmacokinetics, a population pharmacokinetic model for baloxavir acid was developed using 11,846 plasma concentration data items from 1,827 subjects, including 2,341 plasma concentration data items from 664 patients at high risk of influenza complications. A three-compartment model with first-order elimination and first-order absorption with lag time well described the plasma concentration data. Body weight and race were found to be the most important factors influencing clearance and volume of distribution. The exposures in high-risk patients were similar to those in otherwise healthy patients, and no pharmacokinetic difference was identified regarding any risk factors for influenza complications. Exposure-response analyses were performed regarding the time to improvement of symptoms and the reduction in the influenza virus titer in high-risk patients. The analyses suggested that body weight-based dosage, 40 mg for patients weighing

This study investigated the effect of itraconazole, a strong dual inhibitor of cytochrome P450 (CYP) 3A4 and P-glycoprotein (P-gp), on the single dose pharmacokinetics of leniolisib. In order to differentiate the specific contribution of CYP3A from P-gp, the potential interaction with quinidine, a strong inhibitor of P-gp but not CYP3A, was studied as well. Using a fixed-sequence, 3-way crossover design, 20 healthy male subjects received single oral doses of 10 mg leniolisib during three phases separated by a washout: (1) leniolisib alone, (2) 200 mg itraconazole once daily for 9 days plus leniolisib on day 5, and (3) 300 mg quinidine administered 1 h before and 3 h after leniolisib. Itraconazole increased the leniolisib oral drug exposure (AUCinf ) by on average 2.1-fold, whereas the peak drug concentration (Cmax ) was less impacted (1.25-fold). The terminal elimination half-life (T1/2 ) of leniolisib was also increased by ~2-fold. Neither oral AUCinf nor Cmax or T1/2 was found to be altered by quinidine. These findings suggest that the interaction with itraconazole occurred mainly systemically through inhibition of CYP3A, and corroborate our in vitro findings that leniolisib is neither a sensitive CYP3A substrate nor a relevant in vivo substrate for intestinal or hepatic P-gp. Assuming itraconazole levels achieved complete inhibition of CYP3A, the fractional contribution of CYP3A to the overall disposition of leniolisib is estimated to be about 50%. The concomitant use of leniolisib with strong inhibitors of CYP3A as well as strong and moderate inducers of CYP3A is best avoided.

Background Baloxavir marboxil is a prodrug of baloxavir acid which is a selective inhibitor of cap-dependent endonuclease. The global Phase 3 study conducted in the influenza patients at high-risk of influenza complications (CAPSTONE-2) enrolled adult and adolescent patients from 2016 to 2018. Baloxavir marboxil demonstrated significantly shorter time to improvement of influenza symptoms (TTIIS) than placebo. The aim of this study was to build a population pharmacokinetic (PK) model of baloxavir acid and to evaluate the exposure-response relationships in high-risk patients. Methods The population PK analysis was conducted on the pooled data from 13 clinical studies: 10 phase 1 studies, a phase 2 study, and 2 phase 3 studies. A total of 11846 plasma concentrations from 1827 subjects were used for this analysis. The influence of background characteristics including risk factors of influenza complications was assessed on the PK of baloxavir acid. The individual Cmax and AUC were estimated with an empirical Bayesian approach. Exposure-response analysis was conducted for TTIIS and virus titer in the high-risk patients. Results A 3-compartment model with first-order absorption and lag time was selected as a structural PK model, and well described the plasma concentrations. The population PK analysis suggested that (1) AUC in non-Asians was 30.7% lower than that in Asians, (2) body weight significantly affected the exposures to baloxavir acid, (3) the exposures in high-risk patients were similar to those in otherwise healthy patients, and (4) no PK differences were identified regarding the risk factors for influenza complications. The exposure-response analyses showed that the body weight-based dose regimen (40 mg for the patients weighing Conclusion The results of the population PK analysis and exposure-response analyses provide useful information for understanding the pharmacokinetic and pharmacodynamic characteristics of baloxavir marboxil. Disclosures All authors: No reported disclosures.

Pathogenic gain-of-function variants in the genes encoding phosphoinositide 3-kinase δ (PI3Kδ) lead to accumulation of transitional B cells and senescent T cells, lymphadenopathy, and immune deficiency (activated PI3Kδ syndrome [APDS]). Knowing the genetic etiology of APDS afforded us the opportunity to explore PI3Kδ inhibition as a precision-medicine therapy. Here, we report in vitro and in vivo effects of inhibiting PI3Kδ in APDS. Treatment with leniolisib (CDZ173), a selective PI3Kδ inhibitor, caused dose-dependent suppression of PI3Kδ pathway hyperactivation (measured as phosphorylation of AKT/S6) in cell lines ectopically expressing APDS-causative p110δ variants and in T-cell blasts derived from patients. A clinical trial with 6 APDS patients was conducted as a 12-week, open-label, multisite, within-subject, dose-escalation study of oral leniolisib to assess safety, pharmacokinetics, and effects on lymphoproliferation and immune dysregulation. Oral leniolisib led to a dose-dependent reduction in PI3K/AKT pathway activity assessed ex vivo and improved immune dysregulation. We observed normalization of circulating transitional and naive B cells, reduction in PD-1+CD4+ and senescent CD57+CD4− T cells, and decreases in elevated serum immunoglobulin M and inflammatory markers including interferon γ, tumor necrosis factor, CXCL13, and CXCL10 with leniolisib therapy. After 12 weeks of treatment, all patients showed amelioration of lymphoproliferation with lymph node sizes and spleen volumes reduced by 39% (mean; range, 26%-57%) and 40% (mean; range, 13%-65%), respectively. Thus, leniolisib was well tolerated and improved laboratory and clinical parameters in APDS, supporting the specific inhibition of PI3Kδ as a promising new targeted therapy in APDS and other diseases characterized by overactivation of the PI3Kδ pathway. This trial was registered at www.clinicaltrials.gov as #NCT02435173.

Aims The aim was to characterize the population pharmacokinetics of BYL719 in cancer patients and assess the time course of tumour response in relation to drug exposure and dosing schedule. Methods Plasma samples and longitudinal tumour size measurements were collected from 60 patients with advanced solid malignancies who received oral BYL719 once daily (30–450 mg) or twice daily at 120 mg or 200 mg. Non-linear mixed effect modelling was employed to develop the population pharmacokinetic and pharmacodynamic model. Results The pharmacokinetics were best described by a one compartment disposition model and transit compartments accounting for the lag time in absorption. The typical population oral clearance and volume of distribution estimates with their between-subject variability (BSV) were 10 l h−1 (BSV 26%) and 108 l (BSV 28%), respectively. The estimated optimal number of transit compartments was 8.1, with a mean transit time to the absorption compartment of 1.28 h (BSV 32%). The between-occasion variability in the rate and extent of absorption was 46% and 26%, respectively. Tumour growth was modelled using a turnover model characterized by a zero order growth rate of 0.581 cm week1 and a first order death rate of 0.0123 week−1. BYL719 inhibited tumour growth with an IC50 of 100 ng ml−1 (BSV 154%). Model-based predictions showed potential for additional anti-tumour activity of twice daily dosing at total daily dose below 400 mg, but a loss of efficacy if administered less frequently than once daily. Conclusions The proposed model provides a valuable approach for planning future clinical studies and for designing optimized dosing regimens with BYL719.

Background: It is imperative that new drugs demonstrate adequate pharmacokinetic properties, allowing an optimal safety margin and convenient dosing regimens in clinical practice, which then lead to better patient compliance. Such pharmacokinetic properties include suitable peak (maximum) plasma drug concentration (Cmax), area under the plasma concentration-time curve (AUC) and a suitable half-life (t1/2). The Cmax and t1/2 following oral drug administration are functions of the oral clearance (CL/F) and apparent volume of distribution during the terminal phase by the oral route (Vz/F), each of which may be predicted and combined to estimate Cmax and t1/2. Allometric scaling is a widely used methodology in the pharmaceutical industry to predict human pharmacokinetic parameters such as clearance and volume of distribution. In our previous published work, we have evaluated the use of allometry for prediction of CL/F and AUC. In this paper we describe the evaluation of different allometric scaling approaches for the prediction of Cmax, Vz/F and t 1/2 after oral drug administration in man. Methods: Twenty-nine compounds developed at Janssen Research and Development (a division of Janssen Pharmaceutica NV), covering a wide range of physicochemical and pharmacokinetic properties, were selected. The Cmax following oral dosing of a compound was predicted using (i) simple allometry alone; (ii) simple allometry along with correction factors such as plasma protein binding (PPB), maximum life-span potential or brain weight (reverse rule of exponents, unbound Cmax approach); and (iii) an indirect approach using allometrically predicted CL/F and Vz/F and absorption rate constant (ka). The ka was estimated from (i) in vivo pharmacokinetic experiments in preclinical species; and (ii) predicted effective permeability in man (Peff), using a Caco-2 permeability assay. The Vz/F was predicted using allometric scaling with or without PPB correction. The t1/2 was estimated from the allometrically predicted parameters CL/F and Vz/F. Predictions were deemed adequate when errors were within a 2-fold range. Results: Cmax and t1/2 could be predicted within a 2-fold error range for 59% and 66% of the tested compounds, respectively, using allometrically predicted CL/F and Vz/F. The best predictions for Cmax were obtained when ka values were calculated from the Caco-2 permeability assay. The Vz/F was predicted within a 2-fold error range for 72% of compounds when PPB correction was applied as the correction factor for scaling. Conclusions: We conclude that (i) Cmax and t1/2 are best predicted by indirect scaling approaches (using allometrically predicted CL/F and Vz/F and accounting for ka derived from permeability assay); and (ii) the PPB is an important correction factor for the prediction of Vz/F by using allometric scaling. Furthermore, additional work is warranted to understand the mechanisms governing the processes underlying determination of Cmax so that the empirical approaches can be fine-tuned further.

Inherited gain-of-function mutations in PIK3CD encoding PI3Kδ (phosphoinositide 3-kinase delta) lead to accumulation of senescent T cells, lymphadenopathy, splenomegaly and immune-deficiency (Activated PI3Kδ Syndrome, APDS). Clinical manifestations include multilineage cytopenias and susceptibility to B cell Non-Hodgkins Lymphoma. We recently reported use of leniolisib (CDZ173), a novel, potent and selective oral PI3Kd inhibitor in six APDS patients in a 12-week, open-label, multi-center, within-subject dose-escalation study (Rao et al, Blood 23 November 2017). Leniolisib was safe and well tolerated and led to a dose-dependent reduction in PI3K/AKT pathway activity and improved the immune dysregulation with normalization of circulating transitional and naïve B cells and reduction in PD-1+CD4+ and senescent CD57+CD8+ T cells. Elevated serum IgM and other biomarkers including IFNg, TNF, CXCL13 and CXCL10 normalized or decreased with leniolisib. Cytopenias and lymphoproliferation improved in all patients with index lymph node sizes and spleen volumes reduced by 39% and 40%, respectively. Here we report the long term follow up safety and efficacy data in all six patients (Table 1) who have continued treatment with leniolisib in an extension study at 70 mg b.i.d (ClinicalTrials.gov number NCT02859727). These patients have been treated for up to 949 days (as of July 20th 2018). Three of them were lymphoma survivors. Three patients were treated with rapamycin prior to starting leniolisib. No patient in the 12-week clinical trial or in the long term extension study has experienced any significant adverse events. Notably, side effects prevalent with mTOR or other PI3K inhibitors such as diarrhea/colitis, skin rashes, susceptibility to infections or liver enzyme elevation were absent. Three patients have stopped immunoglobulin supplementation as a reflection of the normalization of their B cell function. Cytopenias, including anemia, thrombocyopenia, neutropenia and lymphopenia have continued to improve. (Figure 1: Showing representative improvement of laboratory data including normalization of IgM for patient 002, following 18 months of treatment with leniolisib; Figure2: Showing improvement of lymphoproliferation in CT scans from 2016 and 2018 for Patient 003. This patient stopped leniolisib for 15 months from October 2016 until January 2018 leading to worsening lymphoproliferation that improved promptly on resumption of therapy). Available data on longterm safety, effects on lymphoproliferation and immune dysregulation in the ongoing leniolisib extension study will be shared during the meeting. The results support safe and efficacious long term inhibition of PI3Kδ protein as a new targeted therapeutic approach in APDS and other disorders of nonmalignant lymphopoliferation associated with hyperactive PI3Kinase pathway. Disclosures Rao: novartis: Research Funding. Dalm:Novartis: Research Funding. Sediva:Novartis: Research Funding. van Hagen:Novartis: Research Funding. Cabanski:Novartis: Employment. Valentin:Novartis: Employment. de Buck:Novartis: Employment. Kalis:Novartis: Employment. Hasselberg:Novartis: Employment. Burkhart:Novartis: Employment. Kucher:Novartis: Employment. Sloth:Novartis: Employment. Uzel:Novartis: Research Funding.

Purpose: Phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway activation in patients with HER2-positive (HER2+) breast cancer has been implicated in de novo and acquired trastuzumab resistance. The purpose of this study was to determine the clinical activity of the PI3K inhibitor buparlisib (BKM120) in patients with HER2+ advanced/metastatic breast cancer resistant to trastuzumab-based therapy. Experimental Design: In the dose-escalation portion of this phase I/II study, patients with trastuzumab-resistant locally advanced or metastatic HER2+ breast cancer were treated with daily oral doses of buparlisib and weekly intravenous trastuzumab (2 mg/kg). Dose escalation was guided by a Bayesian logistic regression model with overdose control. Results: Of 18 enrolled patients, 17 received buparlisib. One dose-limiting toxicity of grade 3 general weakness was reported at the 100-mg/day dose level (the single-agent maximum tolerated dose) and this dose level was declared the recommended phase II dose (RP2D) of buparlisib in combination with trastuzumab. Common (>25%) adverse events included rash (39%), hyperglycemia (33%), and diarrhea (28%). The pharmacokinetic profile of buparlisib was not affected by its combination with trastuzumab. At the RP2D, there were two (17%) partial responses, 7 (58%) patients had stable disease (≥6 weeks), and the disease control rate was 75%. Pharmacodynamic studies showed inhibition of the PI3K/AKT/mTOR and RAS/MEK/ERK pathways. Conclusions: In this patient population, the combination of buparlisib and trastuzumab was well tolerated, and preliminary signs of clinical activity were observed. The phase II portion of this study will further explore the safety and efficacy of this combination at the RP2D. Clin Cancer Res; 20(7); 1935–45. ©2014 AACR.

As chemists can easily produce large numbers of new potential drug candidates, there is growing demand for high capacity models that can help in driving the chemistry towards efficacious and safe candidates before progressing towards more complex models. Traditionally, the cardiovascular (CV) safety domain plays an important role in this process, as many preclinical CV biomarkers seem to have high prognostic value for the clinical outcome. Throughout the industry, traditional ion channel binding data are generated to drive the early selection process. Although this assay can generate data at high capacity, it has the disadvantage of producing high numbers of false negatives. Therefore, our company applies the isolated guinea pig right atrium (GPRA) assay early-on in discovery. This functional multi-channel/multi-receptor model seems much more predictive in identifying potential CV liabilities. Unfortunately however, its capacity is limited, and there is no room for full automation. We assessed the correlation between ion channel binding and the GPRA’s Rate of Contraction (RC), Contractile Force (CF), and effective refractory frequency (ERF) measures assay using over six thousand different data points. Furthermore, the existing experimental knowledge base was used to develop a set of in silico classification models attempting to mimic the GPRA inhibitory activity. The Naive Bayesian classifier was used to built several models, using the ion channel binding data or in silico computed properties and structural fingerprints as descriptors. The models were validated on an independent and diverse test set of 200 reference compounds. Performances were assessed on the bases of their overall accuracy, sensitivity and specificity in detecting both active and inactive molecules. Our data show that all in silico models are highly predictive of actual GPRA data, at a level equivalent or superior to the ion channel binding assays. Furthermore, the models were interpreted in terms of the descriptors used to highlight the undesirable areas in the explored chemical space, specifically regions of low polarity, high lipophilicity and high molecular weight. In conclusion, we developed a predictive in silico model of a complex physiological assay based on a large and high quality set of experimental data. This model allows high throughput in silico safety screening based on chemical structure within a given chemical space.

3003 Background: MAPK and PI3K/AKT signaling pathways regulate proliferation, differentiation and cell death in human cancers. Known interaction between the 2 pathways provides the rationale for combining both inhibitors in a phase I study. Methods: The objective is to determine the maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) for oral, daily administered, BKM120 + GSK1120212, mainly in pts with tumors with RAS/RAF mutations (mt). A Bayesian logistic regression model with overdose control guides the dose escalation of the treatment. Secondary objectives include safety, tolerability, PK and efficacy. Results: As of 22.09.11, 49 pts were treated with BKM120 + GSK1120212 as follows: 30mg + 0.5mg, 60mg + 0.5mg, 60mg + 1.0mg, 60mg + 1.5mg, 60mg + 2.0mg, 70mg + 1.5mg, 80mg + 1.0mg, 80mg + 1.5mg. 6 pts had dose-limiting toxicities (DLTs); all were reversible. Grade 3 DLTs were: 3 x stomatitis, 1 x dysphagia, 1 x LVEF decrease, 1 x CK increase, 1 x nausea, 1 x anorexia, 1 x decreased oral intake. MTD and/or RP2D for the combination have not been reached. Most common adverse events (AEs) (>25%), all grades and causality, were dermatitis acneiform, diarrhea (51% each); nausea (41%); vomiting (37%); rash (33%); asthenia (31%); CK increase, decreased appetite, pyrexia or stomatitis (29% each) and hyperglycemia (27%). There were 4 on-treatment deaths unrelated to treatment. AEs led to treatment discontinuation, 17 pts (35%) and interruptions/dose reductions, 25 pts (51%). Apparent steady-states of BKM120 and GSK1120212 were reached by day 28. Plasma concentrations of BKM120 in combination with GSK1120212 were lower than for monotherapy. Exposure to GSK1120212 with BKM120 was similar to that observed in monotherapy studies. 3 confirmed partial responses have been observed in pts with KRAS mt ovarian cancer; 2 lasting >9 months. 2 patients with BRAF mt melanoma, who had previously progressed on BRAF inhibitors, had stable disease, for 1 of whom treatment is still ongoing in cycle 6. Conclusions: BKM120 and GSK1120212 can be safely combined. Signs of clinical activity have been seen in pts with RAS/RAF mt tumors.