Fertility-preserving myeloablative conditioning using single-dose CD117 antibody-drug conjugate in a rhesus gene therapy model.

Hematopoietic stem cell (HSC) gene therapy has curative potential; however, its use is limited by the morbidity and mortality associated with current chemotherapy-based conditioning. Targeted conditioning using antibody-drug conjugates (ADC) holds promise for reduced toxicity in HSC gene therapy. Here we test the ability of an antibody-drug conjugate targeting CD117 (CD117-ADC) to enable engraftment in a non-human primate lentiviral gene therapy model of hemoglobinopathies. Following single-dose CD117-ADC, a >99% depletion of bone marrow CD34 + CD90 + CD45RA- cells without lymphocyte reduction is observed, which results are not inferior to multi-day myeloablative busulfan conditioning. CD117-ADC, similarly to busulfan, allows efficient engraftment, gene marking, and vector-derived fetal hemoglobin induction. Importantly, ADC treatment is associated with minimal toxicity, and CD117-ADC-conditioned animals maintain fertility. In contrast, busulfan treatment commonly causes severe toxicities and infertility in humans. Thus, the myeloablative capacity of single-dose CD117-ADC is sufficient for efficient engraftment of gene-modified HSCs while preserving fertility and reducing adverse effects related to toxicity in non-human primates. This targeted conditioning approach thus provides the proof-of-principle to improve risk-benefit ratio in a variety of HSC-based gene therapy products in humans.

Overall safety of relamorelin in adults with diabetic gastroparesis: Analysis of phase 2a and 2b trial data.

BACKGROUND: Relamorelin, a pentapeptide ghrelin receptor agonist, accelerated gastric emptying significantly and improved symptoms in adults with diabetic gastroparesis in phase 2 trials. AIM: To assess the safety and tolerability of relamorelin across phase 2 trials. METHODS: Safety assessments in patients aged 18-75 years (weight, adverse events [AEs] and laboratory tests) from two randomised, double-blind phase 2 trials (NCT01571297, NCT02357420; results published previously) were reviewed descriptively. Analysis of covariance assessed treatment effect on glycated haemoglobin (HbA1c) and blood glucose post hoc. Phase 2a and 2b trial durations were, respectively, 4 weeks (relamorelin 10 µg once or twice daily [b.d.] or placebo b.d.) and 12 weeks (relamorelin 10, 30 or 100 µg or placebo b.d.) with 1- and 2-week, single-blind placebo run-ins. RESULTS: Among 204 phase 2a and 393 phase 2b patients, respectively, 67% and 62% were female, and 88% and 89% had type 2 diabetes. Proportions of patients reporting serious AEs were similar across treatment groups, as were those with ≥1 treatment-emergent AE (TEAE). TEAE-related discontinuations were proportionally higher in relamorelin groups than placebo. Of 12 serious TEAEs in phase 2a, none occurred in >1 patient. In phase 2b, five serious TEAEs were reported in >1 patient, and one (100 µg) died (urosepsis), all unrelated to relamorelin. In phase 2b, increased HbA1c and fasting blood glucose levels were dose-related (P < 0.0001 and P = 0.0043, respectively). CONCLUSIONS: Relamorelin showed acceptable safety and tolerability in phase 2 trials. Relamorelin may elevate blood glucose: this should be managed proactively in relamorelin-treated patients.

Peficitinib, an Oral Janus Kinase Inhibitor, in Moderate-to-severe Ulcerative Colitis: Results From a Randomised, Phase 2 Study.

BACKGROUND AND AIMS: Janus kinase [JAK] inhibitors have shown efficacy in ulcerative colitis [UC]. We studied the dose-response, efficacy, and safety of peficitinib, an oral JAK inhibitor, in patients with moderate-to-severe UC. METHODS: In this Phase 2b, dose-ranging trial, we evaluated peficitinib at 25 mg once daily [o.d.], 75 mg o.d., 150 mg o.d., and 75 mg twice daily versus placebo for efficacy and safety in 219 patients with moderate-to-severe UC. The primary outcome was peficitinib dose-response at Week 8, with response assessed using Mayo score change from baseline. Secondary endpoints were clinical response, clinical remission, mucosal healing, change from baseline in Inflammatory Bowel Disease Questionnaire [IBDQ], and normalisation of inflammatory biomarkers at Week 8; other secondary endpoints were treatment response through Week 16 and through Week 32 for patients in clinical response at Week 8. Safety was assessed through Week 36 or 4 weeks after the last dose. RESULTS: A statistically significant peficitinib dose-response was not demonstrated at Week 8, although a numerically greater proportion of patients receiving peficitinib ≥75 mg o.d. achieved clinical response, remission, and mucosal healing at Week 8, supported by IBDQ improvement and inflammatory biomarker normalisation. Treatment-emergent adverse event [TEAE] rates reported through Week 8 and the final safety visit were higher in the combined peficitinib group than in the placebo group; patients receiving doses of ≥75 mg o.d. peficitinib reported TEAEs more frequently. CONCLUSIONS: No dose-response in patients with moderate-to-severe UC was demonstrated with peficitinib, but evidence of efficacy was suggested at doses ≥75 mg o.d. The safety profile of peficitinib was consistent with current information. ClinicalTrials.gov NCT01959282.

Telaprevir twice daily is noninferior to telaprevir every 8 hours for patients with chronic hepatitis C.

BACKGROUND & AIMS: We performed an open-label, multicenter, phase 3 study of the safety and efficacy of twice-daily telaprevir in treatment-naive patients with chronic hepatitis C virus (HCV) genotype 1 infection, including those with cirrhosis. METHODS: Patients were randomly assigned to groups treated with telaprevir 1125 mg twice daily or 750 mg every 8 hours plus peginterferon alfa-2a and ribavirin for 12 weeks; patients were then treated with peginterferon alfa-2a and ribavirin alone for 12 weeks if their level of HCV RNA at week 4 was <25 IU/mL or for 36 weeks if their level was higher. The primary objective was to demonstrate noninferiority of telaprevir twice daily versus every 8 hours in producing a sustained virological response 12 weeks after the end of therapy (SVR12) (based on a -11% lower limit of the 95% lower confidence interval for the difference between groups). RESULTS: At baseline, of 740 patients, 85% had levels of HCV RNA ≥800,000 IU/mL, 28% had fibrosis (F3-F4), 14% had cirrhosis (F4), 57% were infected with HCV genotype 1a, and 71% had the non-CC IL28B genotype. Of patients who were treated with telaprevir twice daily, 74.3% achieved SVR12 compared with 72.8% of patients who were treated with telaprevir every 8 hours (difference in response, 1.5%; 95% confidence interval, -4.9% to 12.0%), so telaprevir twice daily is noninferior to telaprevir every 8 hours. All subgroups of patients who were treated with telaprevir twice daily versus those who were treated every 8 hours had similar rates of SVR12. The most frequent adverse events (AEs) in the telaprevir phase were fatigue (47%), pruritus (43%), anemia (42%), nausea (37%), rash (35%), and headache (26%); serious AEs were reported in 9% of patients. Rates of AEs and serious AEs were similar or slightly higher among patients treated with telaprevir every 8 hours. CONCLUSIONS: Based on a phase 3 trial, telaprevir twice daily is noninferior to every 8 hours in producing SVR12, with similar levels of safety and tolerability. These results support use of telaprevir twice daily in patients with chronic HCV genotype 1 infection, including those with cirrhosis. ClinicalTrials.gov, Number: NCT01241760.

Pharmacokinetic interaction between etravirine or rilpivirine and telaprevir in healthy volunteers: A randomized, two-way crossover trial.

Coinfection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) may require treatment with an HIV non-nucleoside reverse transcriptase inhibitor (NNRTI), for example, rilpivirine or etravirine, and an HCV direct-acting antiviral drug such as telaprevir. In a two-panel, two-way, crossover study, healthy volunteers were randomized to receive etravirine 200 mg twice daily ± telaprevir 750 mg every 8 hours or rilpivirine 25 mg once daily ± telaprevir 750 mg every 8 hours. Pharmacokinetic assessments were conducted for each drug at steady-state when given alone and when coadministered; statistical analyses were least-square means with 90% confidence intervals. Telaprevir minimum plasma concentration (Cmin), maximum plasma concentration (Cmax), and area under the concentration-time curve (AUC) decreased 25%, 10%, and 16%, respectively, when coadministered with etravirine and 11%, 3%, and 5%, respectively, when coadministered with rilpivirine. Telaprevir did not affect etravirine pharmacokinetics, but increased rilpivirine Cmin, Cmax, and AUC by 93%, 49%, and 78%, respectively. Both combinations were generally well tolerated. The small decrease in telaprevir exposure when coadministered with etravirine is unlikely to be clinically relevant. The interaction between telaprevir and rilpivirine is not likely to be clinically relevant under most circumstances. No dose adjustments are deemed necessary when they are coadministered.

A highly sensitive and selective method for the determination of leukotriene B4 (LTB4) in ex vivo stimulated human plasma by ultra fast liquid chromatography-tandem mass spectrometry.

Leukotriene B4 (LTB4) is an important inflammatory component in a number of diseases and has been used as a pharmacodynamic (PD) biomarker. In this report, a highly sensitive and selective ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method for the determination of LTB4 in plasma from ex vivo stimulated human blood, using leukotriene B4-d4 (LTB4-d4, contains four deuterium atoms at the 6, 7, 14, and 15 positions) as the internal standard (IS), was developed and validated. The chromatographic separation of LTB4 from its three isomers and an unknown interference peak from human plasma was crucial to achieve accurate determination of 0.2 ng/mL (LLOQ) of LTB4. LTB4 and the IS were extracted with methyl tertiary butyl ether (MTBE) from 200 µL human plasma. Reversed-phase HPLC separation was carried out with a Phenomenex Synergi Hydro-RP column (100mm×3mm, 2.5 µm). MS/MS detection was set at mass transitions of 335.0→194.9 m/z for LTB4 and 339.0→196.9 m/z for LTB4-d4 in Turbo Ionization Spray (TIS) negative mode. The dynamic range of the method is 0.2-200 ng/mL. LTB4 was found to be stable in human plasma for at least three freeze (-20 °C)/thaw cycles, and on the benchtop (room temperature) for at least 6h. The stock solution storage stability study demonstrated that the LTB4 stock solution, in 50:50 acetonitrile:water, was stable at 4 °C for at least 198 days. The processed samples were found to be stable for at least 72 h at room temperature. The long-term sample storage stability test demonstrated that LTB4 human plasma samples were stable at a storage temperature of -20 °C for at least 198 days. In addition, intraday and interday accuracy and precision, sensitivity, linearity, and recovery were evaluated. An additional partial validation was conducted to decrease the plasma sample volume from 200 to 100 µL. All the data reported in this study fulfilled the requirements and recommendations in the FDA guidance for bioanalytical method validation. Comparison of the validated UFLC-MS/MS method with an ELISA method using ex vivo stimulated samples indicated that although results from the two assays correlated relatively well, the UFLC-MS/MS method has been shown to be superior in selectivity and dynamic range to an ELISA method in our study. The validated UFLC-MS/MS method was successfully used to analyze samples generated from two clinical studies. The excellent assay performance and incurred sample reproducibility (ISR) results obtained from the study sample analysis demonstrated the assay is robust and reliable.

Translational evaluation of JNJ-18038683, a 5-hydroxytryptamine type 7 receptor antagonist, on rapid eye movement sleep and in major depressive disorder.

In rodents 5-hydroxytryptamine type 7 (5-HT(7)) receptor blockade has been shown to be effective in models of depression and to increase the latency to rapid eye movement (REM) sleep and decrease REM duration. In the clinic, the REM sleep reduction observed with many antidepressants may serve as a biomarker. We report here the preclinical and clinical evaluation of a 5-HT(7) receptor antagonist, (3-(4-chlorophenyl)-1,4,5,6,7,8-hexahydro-1-(phenylmethyl)pyrazolo[3,4-d]azepine 2-hydroxy-1,2,3-propanetricarboxylate) (JNJ-18038683). In rodents, JNJ-18038683 increased the latency to REM sleep and decreased REM duration, and this effect was maintained after repeated administration for 7 days. The compound was effective in the mouse tail suspension test. JNJ-18038683 enhanced serotonin transmission, antidepressant-like behavior, and REM sleep suppression induced by citalopram in rodents. In healthy human volunteers JNJ-18038683 prolonged REM latency and reduced REM sleep duration, demonstrating that the effect of 5-HT(7) blockade on REM sleep translated from rodents to humans. Like in rats, JNJ-18038683 enhanced REM sleep suppression induced by citalopram in humans, although a drug-drug interaction could not be ruled out. In a double-blind, active, and placebo-controlled clinical trial in 225 patients suffering from major depressive disorder, neither treatment with pharmacologically active doses of JNJ-18038683 or escitalopram separated from placebo, indicating a failed study lacking assay sensitivity. Post hoc analyses using an enrichment window strategy, where all the efficacy data from sites with an implausible high placebo response [placebo group Montgomery-Åsberg Depression Rating Scale (MADRS) < = 12] and from sites with no placebo response (MADRS > = 28) are removed, there was a clinically meaningful difference between JNJ-18038683 and placebo. Further clinical studies are required to characterize the potential antidepressant efficacy of JNJ-18038683.

A brief survey of first-in-human studies.

First-in-human (FIH) studies are a critical step in the drug development process and typically aim to characterize a compound's pharmacokinetics, potential effective concentration or dose, and safety or tolerability margins. Although effort continues to enhance the predictive quality of the selection of FIH doses from preclinical data, and little consensus is available on the design and conduct of FIH studies, detailed surveys describing general approaches taken in FIH studies are useful in the optimization of early-phase clinical drug development. Although allometric scaling techniques continue to provide poor predictive estimates for human pharmacokinetic parameters, FIH starting doses are selected with substantial safety factors applied to human equivalent dose, often in excess of regulatory guidelines. Based on these examples, it appears that relatively conservative 2-fold dose escalations are the most common escalation approach within FIH single ascending dose studies. The combination of conservative dose escalations with low starting doses can result in large FIH trials, consuming both time and resources. Approaches that could enhance the predictive nature of a compound's disposition and adaptive nature of FIH studies could provide a tremendous benefit for drug development.

Simultaneous determination of tolbutamide, omeprazole, midazolam and dextromethorphan in human plasma by LC-MS/MS--a high throughput approach to evaluate drug-drug interactions.

Drug-drug interactions involving cytochrome P450 (CYP450s) are an important factor for evaluation of a new chemical entity (NCE) in drug development. To evaluate the potential inhibitory effects of a NCE on the pharmacokinetics of a cocktail of representative probes of CYP enzymes (midazolam for CYP3A4, tolbutamide for CYP2C9, omeprazole for CYP2C19 and dextromethorphan for CYP2D6) and the safety and tolerability of the NCE in the presence of probe substrates, a high throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of tolbutamide, omeprazole, midazolam and dextromethorphan in human plasma using tolbutamide-d(9), midazolam-d(4), (+/-)-omeprazole-d(3), and dextromethorphan-d(3) as the internal standards (ISs). Human plasma samples of 50 microL were extracted by a simple protein-precipitation procedure and analyzed using a high performance liquid chromatography electrospray tandem mass spectrometer system. Reversed-phase HPLC separation was achieved with a Hypersil GOLD AQ column (50 mm x 4.6 mm, 5 microm). MS/MS detection was set at mass transitions of 271-->172 m/z for tolbutamide, 346-->198 m/z for omeprazole, 326-->291 m/z for midazolam, 272-->171 m/z for dextromethorphan, 280-->172 m/z for tolbutamide-d(9) (IS), 349-->198 m/z for (+/-)-omeprazole-d(3) (IS), 330-->295 m/z for midazolam-d(4) (IS), and 275-->171 m/z for dextromethorphan-d(3) (IS) in positive mode. The high throughput LC-MS/MS method was validated for accuracy, precision, sensitivity, stability, recovery, matrix effects, and calibration range. Acceptable intra-run and inter-run assay precision (<10%) and accuracy (<10%) were achieved over a linear range of 50-50,000 ng/mL for tolbutamide, 1-1000 ng/mL for omeprazole, 0.1-100 ng/mL for midazolam and 0.05-50 ng/mL for dextromethorphan in human plasma. Method robustness was demonstrated by the 100% pass rate of 24 incurred sample analysis runs and all of the 50 clinical study samples used for incurred sample reproducibility (ISR) test having met the acceptance criterion (%Diff within 20%). The overall ISR results for all compounds showed that over 95% of the samples had a %Diff of less than 10%. The method is simple, rapid and rugged, and has been applied successfully to sample analysis in support of a drug-drug interaction study.

Apparent active transport of MDMA is not mediated by P-glycoprotein: a comparison with MDCK and Caco-2 monolayers.

Amphetamines and their methylenedioxy derivatives generically display similar behavioral, physiologic and toxic effects. Inconsistent pharmacokinetic and toxicity data for methylenedioxymethamphetamine (MDMA) may suggest that active drug transporters are interacting with these compounds, and thus altering drug absorption and tissue distribution. In vitro models of CNS accumulation and intestinal drug transport were used to assess efflux transport of MDMA. Madin-Darby kidney cell epithelial (MDCK) monolayers displayed a 4-fold increase in accumulation in the basolateral to apical orientation relative to the apical to basolateral orientation, although no differential accumulation was noted between MDCK-WT and MDCK-MDR1 monolayers. Caco-2 monolayers demonstrated an approximate 2-fold increase in accumulation of MDMA. Exposure of various inhibitors of active drug transporters demonstrated mixed results; ritonavir, progesterone and indomethacin produced an approximately 50% reduction of MDMA transport, while verapamil, MK-571 and probenecid had no effect. Based on these data, it is concluded that MDMA efflux is mediated via the activity of a transporter distinct from P-glycoprotein. The possible inhibitory effects of amphetamines on rhodamine-123 transport were also assessed. MDMA, methylenedioxyamphetamine, amphetamine and methamphetamine, at physiologically relevant concentrations, did not significantly alter the transport of rhodamine-123 in Caco-2 monolayers or the LS180 cell line, suggesting that these compounds do not alter the function of P-glycoprotein.

Apparent mechanism-based inhibition of human CYP2D6 in vitro by paroxetine: comparison with fluoxetine and quinidine.

Paroxetine, a selective serotonin reuptake inhibitor, is a potent inhibitor of cytochrome P450 2D6 (CYP2D6) activity, but the mechanism of inhibition is not established. To determine whether preincubation affects the inhibition of human liver microsomal dextromethorphan demethylation activity by paroxetine, we used a two-step incubation scheme in which all of the enzyme assay components, minus substrate, are preincubated with paroxetine. The kinetic parameters of inhibition were also estimated by varying the time of preincubation as well as the concentration of inhibitor. From these data, a Kitz-Wilson plot was constructed, allowing the estimation of both an apparent inactivator concentration required for half-maximal inactivation (K(I)) and the maximal rate constant of inactivation (k(INACT)) value for this interaction. Preincubation of paroxetine with human liver microsomes caused an approximately 8-fold reduction in the IC(50) value (0.34 versus 2.54 microM). Time-dependent inhibition was demonstrated with an apparent K(I) of 4.85 microM and an apparent k(INACT) value of 0.17 min(-1). Spectral scanning of CYP2D6 with paroxetine yielded an increase in absorbance at 456 nm suggesting paroxetine inactivation of CYP2D6 via the formation of a metabolite intermediate complex. This pattern is consistent with the metabolism of the methylenedioxy substituent in paroxetine; such substituents may produce mechanism-based inactivation of cytochrome P450 enzymes. In contrast, quinidine and fluoxetine, both of which are inhibitors of CYP2D6 activity, did not exhibit a preincubation-dependent increase in inhibitory potency. These data are consistent with mechanism-based inhibition of CYP2D6 by paroxetine but not by quinidine or fluoxetine.