Mechanistic modeling projections of antibody persistence after homologous booster regimens of COVID-19 vaccine Ad26.COV2.S in humans.

Mechanistic model-based simulations can be deployed to project the persistence of humoral immune response following vaccination. We used this approach to project the antibody persistence through 24 months from the data pooled across five clinical trials in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-seronegative participants following vaccination with Ad26.COV2.S (5 × 1010 viral particles), given either as a single-dose or a homologous booster regimen at an interval of 2, 3, or 6 months. Antibody persistence was quantified as the percentage of participants with detectable anti-spike binding and wild-type virus neutralizing antibodies. The projected overall 24-month persistence after single-dose Ad26.COV2.S was 70.5% for binding antibodies and 55.2% for neutralizing antibodies, and increased after any homologous booster regimen to greater than or equal to 89.9% for binding and greater than or equal to 80.0% for neutralizing antibodies. The estimated model parameters quantifying the rates of antibody production attributed to short-lived and long-lived plasma cells decreased with increasing age, whereas the rate of antibody production mediated by long-lived plasma cells was higher in women relative to men. Accordingly, a more pronounced waning of antibody responses was predicted in men aged greater than or equal to 60 years and was markedly attenuated following any homologous boosting regimen. The findings suggest that homologous boosting might be a viable strategy for maintaining protective effects of Ad26.COV2.S for up to 24 months following prime vaccination. The estimation of mechanistic modeling parameters identified the long-lived plasma cell pathway as a key contributor mediating antibody persistence following single-dose and homologous booster vaccination with Ad26.COV2.S in different subgroups of recipients stratified by age and sex.

Population Pharmacokinetics and Exposure-Response with Teclistamab in Patients With Relapsed/Refractory Multiple Myeloma: Results From MajesTEC-1.

BACKGROUND: Teclistamab, a B-cell maturation antigen × CD3 bispecific antibody, is approved in patients with relapsed/refractory multiple myeloma (RRMM) who have previously received an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 antibody. OBJECTIVE: We report the population pharmacokinetics of teclistamab administered intravenously and subcutaneously (SC) and exposure-response relationships from the phase I/II, first-in-human, open-label, multicenter MajesTEC-1 study. METHODS: Phase I of MajesTEC-1 consisted of dose escalation and expansion at the recommended phase II dose (RP2D; 1.5 mg/kg SC weekly, preceded by step-up doses of 0.06 and 0.3 mg/kg); phase II investigated the efficacy of teclistamab RP2D in patients with RRMM. Population pharmacokinetics and the impact of covariates on teclistamab systemic exposure were assessed using a 2-compartment model with first-order absorption for SC and parallel time-independent and time-dependent elimination pathways. Exposure-response analyses were conducted, including overall response rate (ORR), duration of response (DoR), progression-free survival (PFS), overall survival (OS), and the incidence of grade ≥ 3 anemia, neutropenia, lymphopenia, leukopenia, thrombocytopenia, and infection. RESULTS: In total, 4840 measurable serum concentration samples from 338 pharmacokinetics-evaluable patients who received teclistamab were analyzed. The typical population value of time-independent and time-dependent clearance were 0.449 L/day and 0.547 L/day, respectively. The time-dependent clearance decreased rapidly to < 10% after 8 weeks of teclistamab treatment. Patients who discontinue teclistamab after the 13th dose are expected to have a 50% reduction from Cmax in teclistamab concentration at a median (5th to 95th percentile) time of 15 days (7-33 days) after Tmax and a 97% reduction from Cmax in teclistamab concentration at a median time of 69 days (32-163 days) after Tmax. Body weight, multiple myeloma type (immunoglobulin G vs non-immunoglobulin G), and International Staging System (ISS) stage (II vs I and III vs I) were statistically significant covariates on teclistamab pharmacokinetics; however, these covariates had no clinically relevant effect on the efficacy of teclistamab at the RP2D. Across all doses, ORR approached a plateau at the concentration range associated with RP2D, and in patients who received the RP2D, a flat exposure-response curve was observed. No apparent relationship was observed between DoR, PFS, OS, and the incidence of grade ≥3 adverse events across the predicted exposure quartiles. CONCLUSION: Body weight, myeloma type, and ISS stage impacted systemic teclistamab exposure without any clinically relevant effect on efficacy. The exposure-response analyses for ORR showed a positive trend with increasing teclistamab systemic exposure, with a plateau at the RP2D, and there was no apparent exposure-response trend for safety or other efficacy endpoints. These analyses support the RP2D of teclistamab in patients with RRMM. CLINICAL TRIAL REGISTRATION: NCT03145181 (phase I, 09 May 2017); NCT04557098 (phase II, 21 September 2020).

Population Pharmacokinetic and Exposure-Safety Analyses of Ibrutinib for the Treatment of Chronic Graft-Versus-Host Disease.

The population pharmacokinetic (PK) and exposure-response (E-R) analyses for the safety of ibrutinib for the treatment of chronic graft-versus-host disease (cGVHD) is presented. This work aims to develop a population PK model for ibrutinib based on data from clinical studies in subjects with cGVHD, to evaluate the impact of intrinsic and extrinsic factors on PK parameters as well as systemic exposure levels, and to assess an E-R relationship for selected safety end points. Pooled data from 162 subjects with cGVHD enrolled in 4 clinical studies were included in the population PK analysis. In the studies, an ibrutinib dose of 420 mg once daily was administered orally. With the exception of 1 study, the study protocols instructed for a reduction of the ibrutinib dose to 140 or 280 mg once daily, depending on concomitant CYP3A inhibitor use. Concomitant CYP3A inhibitor use was found to be a primary covariate for relative bioavailability (F1): the F1 value increased 2.22-fold with concomitant moderate CYP3A inhibitors and 3.09-fold with concomitant strong CYP3A inhibitors, compared with the F1 value in the absence of CYP3A inhibitors. In addition, Japanese ethnicity led to an F1 value that was 1.70-fold higher than that in the non-Japanese population. Simulations using the final PK model suggest that ibrutinib exposure was appropriately controlled within the therapeutic range in the entire cGVHD population by applying dose reductions depending on the use of CYP3A inhibitors, and that additional dose modification for the Japanese population would not be required. The subsequent E-R analysis suggests no apparent association between the systemic exposure to ibrutinib and the selected safety end points.

Pharmacokinetic/Pharmacodynamic Analysis of Guselkumab for Treatment of Palmoplantar Pustulosis: Clinical Implications of Guselkumab Dose, Disease Severity, and Smoking in Japanese Patients.

Guselkumab is a human IgG1λ monoclonal antibody that has been approved for treatment of multiple immunologic diseases including palmoplantar pustulosis in Japan. The efficacy of guselkumab in reducing disease severity as compared with placebo has been demonstrated in phase 2 and 3 clinical studies. In some patients assigned to the placebo treatment, worsening of Palmoplantar Pustulosis Area and Severity Index (PPPASI) score was noted. Most of these patients were smokers, raising a possibility of an association of smoking with the disease progression. To understand the clinical implications of guselkumab dose, baseline disease severity, and smoking on the treatment effect and describe the longitudinal relationship between guselkumab exposure and the PPPASI score, a pharmacokinetic/pharmacodynamic modeling analysis was conducted using the pooled data from 1 phase 2 and 1 phase 3 study. Data from 207 Japanese patients (77% women and 60% smokers) with a median PPPASI score of 24.6 were included in the analysis. The observed treatment efficacy (the PPPASI score reduction) appeared to be similar at the current approved dose (100 mg) and the higher dose (200 mg). A greater PPPASI score reduction (in absolute points) is expected in patients with higher baseline PPPASI score (severe disease). However, the higher baseline did not translate to larger magnitude of the change from baseline (in percentage) in the PPPASI score. Incorporating a linear disease progression effect in the model significantly decreased the Nonlinear Mixed Effects Modeling objective function value (P < .001). Smoking status appeared to be related to disease worsening in some patients, but the covariate did not reach statistical significance in the model.

Correction to: Skin rash following Administration of Apalutamide in Japanese patients with Advanced Prostate Cancer: an integrated analysis of the phase 3 SPARTAN and TITAN studies and a phase 1 open-label study.

An amendment to this paper has been published and can be accessed via the original article.

Skin rash following Administration of Apalutamide in Japanese patients with Advanced Prostate Cancer: an integrated analysis of the phase 3 SPARTAN and TITAN studies and a phase 1 open-label study.

BACKGROUND: A higher incidence of apalutamide-related skin rash has been observed in Japanese patients with prostate cancer (PC). METHODS: This integrated analysis of data of Japanese patients from 2 global Phase 3 studies, SPARTAN ( NCT01946204 ; patients with non-metastatic castration-resistant PC [nmCRPC]) and TITAN ( NCT02489318 ; patients with metastatic castration-sensitive PC [mCSPC]), and the Phase 1 study 56021927PCR1008 ( NCT02162836 ; patients with metastatic CRPC [mCRPC]), assessed clinical risk factors of apalutamide-related skin rash as well as the potential correlation with plasma exposure to apalutamide. Kaplan-Meier method was used for time-to-event analyses. Clinical risk factors for skin rash were assessed using odds ratio. RESULTS: Data from 68 patients (SPARTAN: n = 34, TITAN: n = 28, 56021927PCR1008: n = 6) receiving apalutamide 240 mg orally once-daily were analyzed. Rash (13 [19.1%]) and maculo-papular rash (11 [16.2%]) were the most frequently reported skin rash. All Grade and Grade 3 skin rash occurred in 35 (51.5%) and 10 (14.7%) patients, respectively. Most (85.7%) skin rash occurred within 4 months of apalutamide initiation and resolved in a median time of 1 month following the use of antihistamines, topical or systemic corticosteroids, with/without apalutamide dose interruptions/reductions. Median time-to-remission of first incidence of rash and maximum grade incidence of rash were 1.0 month (IQR: 0.36-1.81) and 1.0 month (IQR: 0.30-2.43), respectively. No significant clinical risk factors for the incidence of skin rash were observed. Areas under the curve (0-24 h) (AUC0-24, ss) at steady-state of plasma apalutamide concentration were numerically slightly higher in patients with skin rash than those without. CONCLUSIONS: No clinical risk factors for rash could be detected. There is a potential correlation between incidence of skin rash and plasma exposure to apalutamide. In general, apalutamide-related skin rash is easily managed, with appropriate treatment with or without dose adjustment. TRIAL REGISTRATION: Retrospective pooled analysis of NCT01946204 , NCT02489318 , and NCT02162836 .

Structure-Guided Design of Substituted Biphenyl Butanoic Acid Derivatives as Neprilysin Inhibitors.

Inhibition of neprilysin (NEP) is widely studied as a therapeutic target for the treatment of hypertension, heart failure, and kidney disease. Sacubitril/valsartan (LCZ696) is a drug approved to reduce the risk of cardiovascular death in heart failure patients with reduced ejection fraction. LBQ657 is the active metabolite of sacubitril and an inhibitor of NEP. Previously, we have reported the crystal structure of NEP bound with LBQ657, whereby we noted the presence of a subsite in S1' that has not been explored before. We were also intrigued by the zinc coordination made by one of the carboxylic acids of LBQ657, leading us to explore alternative linkers to efficiently engage zinc for NEP inhibition. Structure-guided design culminated in the synthesis of selective, orally bioavailable, and subnanomolar inhibitors of NEP. A 17-fold boost in biochemical potency was observed upon addition of a chlorine atom that occupied the newly found subsite in S1'. We report herein the discovery and preclinical profiling of compound 13, which paved the path to our clinical candidate.

Comparative and quantitative assessment on statin efficacy and safety: insights into inter-statin and inter-individual variability via dose- and exposure-response relationships.

Introduction: Statins are prescribed widely for cholesterol-lowering therapy, but it is known that their efficacy and safety profiles vary, despite the shared pharmacophore and pharmacological target. The immense body of related clinical and preclinical data offers a unique opportunity to explore the possible factors underlying inter-statin and inter-individual variabilities.Area covered: Clinical and preclinical data from various statins were compiled with regard to the efficacy (cholesterol-lowering effect) and safety (muscle toxicity). Based on the compiled data, dose- and exposure-response relationships were explored to obtain mechanistic and quantitative insights into the variations in the efficacy and safety profiles of statins.Expert opinion: Our analyses indicated that the inter-statin variability in the cholesterol-lowering effect may be mainly attributable to variations in potency of inhibition of the pharmacological target, rather than variations in drug exposure at the site of drug action. However, the drug exposure at the sites of drug action (i.e., the liver for efficacy and the muscle for safety) may contribute to the differences in the efficacy and safety observed in individual patients.

An open-label, phase 1 study of androgen receptor antagonist, apalutamide in Japanese patients with metastatic castration-resistant prostate cancer.

BACKGROUND: Apalutamide, a nonsteroidal potent androgen receptor antagonist, was safe and effective in patients with non-metastatic castration-resistant prostate cancer (nmCRPC) and metastatic-CRPC (mCRPC) in global studies. In this phase 1 study, safety, pharmacokinetics (PK), and efficacy of apalutamide were evaluated in Japanese patients with mCRPC. METHODS: In this open-label, multi-center study, patients received apalutamide 240 mg (once-daily, orally) for first 1 week (PK week) during which PK parameters were assessed. 1 week later (Cycle 1 Day1), after reassessing safety, continuous daily dosing (4 weeks/cycle; once-daily orally) was initiated. Endpoints evaluated were: safety, tolerability, PK and antitumour efficacy of apalutamide. Dose-limiting toxicities (DLTs) were evaluated during PK week and Cycle 1. RESULTS: All six patients received apalutamide. The most common treatment-emergent adverse events (TEAEs) were abdominal discomfort, nasopharyngitis, dysgeusia, rash, and hot flush [2/6 patients (33.3%) each]. No death or DLTs were reported. Grade 3 TEAEs were spinal-cord compression and renal disorder (1/6 patient each). In continuous daily dosing period, PK steady-state of apalutamide was reached approximately by week 4. A significant accumulation of apalutamide was observed (mean accumulation index 3.55), based on AUC0-24. Median (range) serum prostate-specific antigen level decreased from 54.42 (8.92-310.11) ng/mL at baseline to 11.70 (0.37-47.74) ng/mL at week 12 with ≥ 50% reduction in 4/6 (66.7%) patients and 90% reduction in 2/6 (33.3%) patients. CONCLUSION: Apalutamide had manageable safety profile, without any DLT or any new safety signals, and favourable efficacy in Japanese mCRPC patients. Thus, it was ascertained to be an adequate dosage regimen in Japanese mCRPC patients. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02162836.

Pharmacokinetics and Safety of Mavatrep (JNJ-39439335), a TRPV1 Antagonist in Healthy Japanese and Caucasian Men: A Double-Blind, Randomized, Placebo-Controlled, Sequential-Group Phase 1 Study.

This single-center, double-blind, placebo-controlled, sequential-group phase 1 study evaluated the safety, tolerability, and pharmacokinetics (PK) of mavatrep (JNJ-39439335), a transient receptor potential vanilloid 1 antagonist, in healthy Japanese and caucasian subjects. In part 1, a single-ascending-dose study, 50 subjects (25 each healthy Japanese and caucasians) were enrolled and received a single oral dose of 10, 25, or 50 mg mavatrep. Caucasian subjects were matched to Japanese subjects with respect to age (±5 years) and body mass index (±5 kg/m2 ). In part 2, a multiple-ascending-dose study, 36 Japanese subjects were enrolled and received once-daily oral doses of 10, 25, or 50 mg of mavatrep for 21 days. The single-dose PK of mavatrep and its metabolites was similar in the Japanese and caucasian subjects after adjustment of body weight. Following multiple dosing in Japanese subjects, a steady-state condition was reached in approximately 14 days. M2 and M3 are major circulating metabolites with mean exposure > 10% of mavatrep. Nonrenal clearance was the major route of elimination for mavatrep, M2, and M3. Mavatrep exhibited a long half-life, ranging from 68 to 101 and 82-130 hours for Japanese and caucasian subjects, respectively. After single and multiple dosing, mavatrep was well tolerated. The most common adverse events observed were thermohypoesthesia, feeling cold, chills, and feeling hot. Mavatrep and its metabolites exhibited similar PK profiles after single ascending doses in healthy Japanese and caucasian men.

Discovery of a Novel Piperidine-Based Inhibitor of Cholesteryl Ester Transfer Protein (CETP) That Retains Activity in Hypertriglyceridemic Plasma.

Herein we describe the discovery and characterization of a novel, piperidine-based inhibitor of cholesteryl ester transfer protein (CETP) with a core structure distinct from other reported CETP inhibitors. A versatile synthesis starting from 4-methoxypyridine enabled an efficient exploration of the SAR, giving a lead molecule with potent CETP inhibition in human plasma. The subsequent optimization focused on improvement of pharmacokinetics and mitigation of off-target liabilities, such as CYP inhibition, whose improvement correlated with increased lipophilic efficiency. The effort led to the identification of an achiral, carboxylic acid-bearing compound 16 (TAP311) with excellent pharmacokinetics in rats and robust efficacy in hamsters. Compared to anacetrapib, the compound showed substantially reduced lipophilicity, had only modest distribution into adipose tissue, and retained potency in hypertriglyceridemic plasma in vitro and in vivo. Furthermore, in contrast to torcetrapib, the compound did not increase aldosterone secretion in human adrenocortical carcinoma cells nor in chronically cannulated rats. On the basis of its preclinical efficacy and safety profile, the compound was advanced into clinical trials.

Optimization of Allosteric With-No-Lysine (WNK) Kinase Inhibitors and Efficacy in Rodent Hypertension Models.

The observed structure-activity relationship of three distinct ATP noncompetitive With-No-Lysine (WNK) kinase inhibitor series, together with a crystal structure of a previously disclosed allosteric inhibitor bound to WNK1, led to an overlay hypothesis defining core and side-chain relationships across the different series. This in turn enabled an efficient optimization through scaffold morphing, resulting in compounds with a good balance of selectivity, cellular potency, and pharmacokinetic profile, which were suitable for in vivo proof-of-concept studies. When dosed orally, the optimized compound reduced blood pressure in mice overexpressing human WNK1, and induced diuresis, natriuresis and kaliuresis in spontaneously hypertensive rats (SHR), confirming that this mechanism of inhibition of WNK kinase activity is effective at regulating cardiovascular homeostasis.

Small-molecule WNK inhibition regulates cardiovascular and renal function.

The With-No-Lysine (K) (WNK) kinases play a critical role in blood pressure regulation and body fluid and electrolyte homeostasis. Herein, we introduce the first orally bioavailable pan-WNK-kinase inhibitor, WNK463, that exploits unique structural features of the WNK kinases for both affinity and kinase selectivity. In rodent models of hypertension, WNK463 affects blood pressure and body fluid and electro-lyte homeostasis, consistent with WNK-kinase-associated physiology and pathophysiology.

Synthesis of Paclitaxel. 1. Synthesis of the ABC Ring of Paclitaxel by SmI2-Mediated Cyclization.

A convergent synthesis of the ABC ring of antitumor natural product paclitaxel (Taxol) is described. SmI2-mediated reductive cyclization of an allylic benzoate possessing an aldehyde function, synthesized from tri-O-acetyl-d-glucal and 1,3-cyclohexanedione, smoothly afforded the highly strained 6-8-6 tricarbocyclic structure in 66% yield.

Overcoming hERG issues for brain-penetrating cathepsin S inhibitors: 2-cyanopyrimidines. Part 2.

We describe here orally active and brain-penetrant cathepsin S selective inhibitors, which are virtually devoid of hERG K(+) channel affinity, yet exhibit nanomolar potency against cathepsin S and over 100-fold selectivity to cathepsin L. The new non-peptidic inhibitors are based on a 2-cyanopyrimidine scaffold bearing a spiro[3.5]non-6-yl-methyl amine at the 4-position. The brain-penetrating cathepsin S inhibitors demonstrate potential clinical utility for the treatment of multiple sclerosis and neuropathic pain.

4-Amino-2-cyanopyrimidines: novel scaffold for nonpeptidic cathepsin S inhibitors.

We describe here a novel 4-amino-2-cyanopyrimidine scaffold for nonpeptidomimetic cathepsin S selective inhibitors. Some of the synthesized compounds have sub-nanomolar potency and high selectivity toward cathepsin S along with promising pharmacokinetic and physicochemical properties. The key structural features of the inhibitors consist of a combination of a spiro[2.5]oct-6-ylmethylamine P2 group at the 4-position, a small or polar P3 group at the 5-position and/or a polar group at the 6-position of the pyrimidine.

Concise syntheses of cystothiazoles A, C, D, and melithiazol B.

A convergent synthesis of cystothiazoles C 1 and D 3 was achieved based on Julia coupling between the functionalized aldehyde 5b, corresponding to left half of the final molecule, and aryl sulfone 6 or 7, bearing a bithiazole moiety, corresponding to right half. Methylation of 1 and 3 gave cystothiazole A 2 and melithiazol B 4, respectively. The overall yield (5 steps from (2R,3S)-3-methylpent-4-yne-1,2-diol 10; 57%) of 5b via the present route was improved in comparison to that of the previously reported functionalized aldehyde 5a (7 steps from 10; 13%). By applying the modified Julia coupling method, selectivity (6E/6Z=20 : 1-26 : 1) toward the (6E)-form of the coupled products (15 or 19) against the corresponding (6Z)-form was improved in comparison to the Wittig method (6E/6Z=4 : 1-6.9 : 1).