Safety, Tolerability, and Pharmacokinetics of Single and Multiple Ascending Intravenous Infusions of PF-07304814 (Lufotrelvir) in Participants Hospitalized With COVID-19.

Background: An urgent need remains for antiviral therapies to treat patients hospitalized with COVID-19. PF-07304814-the prodrug (lufotrelvir) and its active moiety (PF-00835231)-is a potent inhibitor of the SARS-CoV-2 3CL protease. Method: Eligible participants were 18 to 79 years old and hospitalized with confirmed COVID-19. This first-in-human phase 1b study was designed with 2 groups: single ascending dose (SAD) and multiple ascending dose (MAD). Participants could receive local standard-of-care therapy. In SAD, participants were randomized to receive a 24-hour infusion of lufotrelvir/placebo. In MAD, participants were randomized to receive a 120-hour infusion of lufotrelvir/placebo. The primary endpoint was to assess the safety and tolerability of lufotrelvir. The secondary endpoint was to evaluate the pharmacokinetics of lufotrelvir and PF-00835231. Results: In SAD, participants were randomized to receive 250 mg lufotrelvir (n = 2), 500 mg lufotrelvir (n = 2), or placebo (n = 4) by continuous 24-hour infusion. In MAD, participants were randomized to receive 250 mg lufotrelvir (n = 7), 500 mg lufotrelvir (n = 6), or placebo (n = 4) by continuous 120-hour infusion. No adverse events or serious adverse events were considered related to lufotrelvir. At doses of 250 and 500 mg, concentrations for the prodrug lufotrelvir and active moiety PF-00835231 increased in a dose-related manner. Unbound concentrations of the lufotrelvir active metabolite reached steady state approximately 2- and 4-fold that of in vitro EC90 following 250- and 500-mg doses, respectively. Conclusions: These safety and pharmacokinetic findings support the continued evaluation of lufotrelvir in clinical studies. Clinical Trials Registration. ClinicalTrials.gov NCT04535167.

Mixed meal tolerance testing highlights in diabetes altered branched-chain ketoacid metabolism and pathways associated with all-cause mortality.

BACKGROUND: Elevated BCAA levels are strongly associated with diabetes, but how diabetes affects BCAA, branched-chain ketoacids (BCKAs), and the broader metabolome after a meal is not well known. OBJECTIVE: To compare quantitative BCAA and BCKA levels in a multiracial cohort with and without diabetes after a mixed meal tolerance test (MMTT) as well as to explore the kinetics of additional metabolites and their associations with mortality in self-identified African Americans. METHODS: We administered an MMTT to 11 participants without obesity or diabetes and 13 participants with diabetes (treated with metformin only) and measured the levels of BCKAs, BCAAs, and 194 other metabolites at 8 time points across 5 h. We used mixed models for repeated measurements to compare between group metabolite differences at each timepoint with adjustment for baseline. We then evaluated the association of top metabolites with different kinetics with all-cause mortality in the Jackson Heart Study (JHS) (N = 2441). RESULTS: BCAA levels, after adjustment for baseline, were similar at all timepoints between groups, but adjusted BCKA kinetics were different between groups for α-ketoisocaproate (P = 0.022) and α-ketoisovalerate (P = 0.021), most notably diverging at 120 min post-MMTT. An additional 20 metabolites had significantly different kinetics across timepoints between groups, and 9 of these metabolites-including several acylcarnitines-were significantly associated with mortality in JHS, irrespective of diabetes status. The highest quartile of a composite metabolite risk score was associated with higher mortality (HR:1.57; 1.20, 2.05, P = 0.00094) than the lowest quartile. CONCLUSIONS: BCKA levels remained elevated after an MMTT among participants with diabetes, suggesting that BCKA catabolism may be a key dysregulated process in the interaction of BCAA and diabetes. Metabolites with different kinetics after an MMTT may be markers of dysmetabolism and associated with increased mortality in self-identified African Americans.

A phase 2a, randomized, double-blind, placebo-controlled, three-arm, parallel-group study to assess the efficacy, safety, tolerability and pharmacodynamics of PF-06835919 in patients with non-alcoholic fatty liver disease and type 2 diabetes.

AIM: To assess the safety, tolerability and pharmacodynamics (PD) of the ketohexokinase inhibitor PF-06835919 in participants with non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2D). MATERIALS AND METHODS: This double-blind, placebo-controlled, parallel-group study enrolled adults with NAFLD (≥ 8% whole liver fat [WLF] using MRI proton density fat fraction [MRI-PDFF]) and T2D on stable doses of metformin (≥ 500 mg/day). Participants received once-daily placebo, PF-06835919 150 or 300 mg for 16 weeks. Randomization (1:1:1) was via an interactive response technology system. Endpoints included percentage change from baseline (CFB) in WLF using MRI-PDFF (primary endpoint) and CFB in HbA1c (co-primary endpoint) at 16 weeks, PD, safety and tolerability. RESULTS: Among 164 participants randomized and treated, 145 completed the treatment (placebo, n = 50; PF-06835919 150 mg, n = 46; PF-06835919 300 mg, n = 49). At week 16, least squares mean (90% confidence interval) percentage CFB in WLF was -5.26% (-12.86%, 2.99%), -17.05% (-24.01%, -9.46%) and -19.13% (-25.51%, -12.20%) in the placebo, PF-06835919 150-mg and 300-mg groups, respectively (PF-06835919 300-mg group vs. placebo, P = .0288). Modest numerical reductions in HbA1c were observed in all groups that did not reach statistical significance. Treatment-emergent adverse event incidence was similar across groups (40.7%, 45.5% and 32.7% in the placebo, PF-06835919 150-mg and 300-mg groups, respectively), with no apparent dose-related trend. CONCLUSIONS: PF-06835919 administration over 16 weeks was generally safe and well tolerated and resulted in reductions in WLF in participants with NAFLD and T2D.

Safety, Tolerability, and Pharmacokinetics of Multiple Repeated Oral Doses of the α2/3/5-Subtype Selective GABAA -Positive Allosteric Modulator PF-06372865 in Healthy Volunteers.

Multiple-dose pharmacokinetics (PK) and safety were investigated in this phase 1 study of PF-06372865, a positive allosteric modulator of α2/3/5 subunit-containing γ-aminobutyric acid A receptors (NCT03351751). In 2 cohorts (7-8 PF-06372865 and 2 placebo in each cohort), healthy adult subjects received twice-daily oral doses of PF-06372865 for 21 days, which included titration in the first 7 days, followed by a maintenance dose of 25 mg twice daily (Cohort 1) and 42.5 mg twice daily (Cohort 2) for 14 days. Serial PK samples were collected on days 1 and 21. Nineteen subjects were assigned to study treatments; 18 completed the study. Approximate dose-proportional increases in maximum plasma concentratin and area under the plasma concentration-time curve over the dosing interval were observed. PF-06372865 was rapidly absorbed with a median time to maximum concentration of 1 to 2 hours following both single- and multiple-dose administration. Mean terminal elimination half-life on day 21 was approximately 11 hours in both cohorts. All adverse events were mild; the most frequently reported was dizziness. After titration, there were no reports of somnolence. There were no clinically significant safety findings, including a lack of withdrawal symptoms on discontinuation of treatment. These results demonstrate that PF-06372865 is safe and well tolerated at doses estimated to achieve high receptor occupancy (>80%), a profile differentiated from nonselective benzodiazepines.

Is High Placebo Response Really a Problem in Depression Trials? A Critical Re-analysis of Depression Studies.

Objective: We investigated the accuracy of the often-stated assumption that placebo nonadditivity and an increasing placebo response are major problems in clinical trials and the cause of a trend for smaller treatment effects observed in clinical trials for major depressive disorder (MDD) in recent years. Method of research: We reviewed data from 122 MDD trials conducted between the years 1983 and 2010 (analyzed originally by Undurraga and Baldessarini in 2012) to determine whether the data support the assumption of placebo additivity. Statistical techniques, such as conventional least squares regression, orthogonal least squares regression and locally weighted loess smoothing, were applied to the data set. Results: Re-analysis of the data set showed the active and placebo responses to be highly correlated, to the degree that would be expected assuming placebo additivity, when random variability in both active and placebo response is considered. Despite the placebo responses in MDD trials increasing up to approximately the year 1998, we found no evidence that it has continued to increase since this date, or that it has been the cause of smaller reported treatment effects in recent years. Conclusion: Attempts to reduce the placebo response are unlikely to increase the treatment effect since they are likely to reduce drug nonspecific effects in the treatment arm by a similar amount. Thus, it should come as no surprise that trial designs set up with the sole purpose of reducing placebo response fail to discernibly benefit our ability to identify new effective treatments.

Analgesic potential of PF-06372865, an α2/α3/α5 subtype-selective GABAA partial agonist, in humans.

BACKGROUND: This study investigated the analgesic effects of two doses (15 and 65 mg) of PF-06372865, a novel α2/α3/α5 gamma-aminobutyric acid A (GABAA) subunit selective partial positive allosteric modulator (PAM), compared with placebo and pregabalin (300 mg) as a positive control. METHODS: We performed a randomised placebo-controlled crossover study (NCT02238717) in 20 healthy subjects, using a battery of pain tasks (electrical, pressure, heat, cold and inflammatory pain, including a paradigm of conditioned pain modulation). Pharmacodynamic measurements were performed at baseline and up to 10 h after dose. RESULTS: A dose of 15 mg PF-06372865 increased pain tolerance thresholds (PTTs) for pressure pain at a ratio of 1.11 (90% confidence interval [CI]: 1.02, 1.22) compared with placebo. A dose of 65 mg PF-06372865 led to an increase in PTT for the cold pressor at a ratio of 1.17 (90% CI: 1.03, 1.32), and pressure pain task: 1.11 (90% CI: 1.01, 1.21). Pregabalin showed an increase in PTT for pressure pain at a ratio of 1.15 (95% CI: 1.06, 1.26) and cold pressor task: 1.31 (90% CI: 1.16, 1.48). CONCLUSION: We conclude that PF-06372865 has analgesic potential at doses that do not induce significant sedation or other intolerable adverse events limiting its clinical use. In addition, the present study established the potential role for this battery of pain tasks as a tool in the development of analgesics with a novel mechanism of action, for the treatment of various pain states including neuropathic pain and to establish proof-of-concept. CLINICAL TRIALS REGISTRATION: NCT0223871.

Photosensitive epilepsy: Robust clinical efficacy of a selective GABA potentiator.

OBJECTIVE: The objective of this phase 2a study was to assess the activity of PF-06372865, a positive allosteric modulator (PAM) of α2/3/5 subunit-containing GABAA receptors with minimal activity at α1-containing receptors, which are believed to mediate many of the adverse events associated with benzodiazepines, in the epilepsy photosensitivity model as a proof-of-principle of efficacy. METHODS: Seven participants with a photoparoxysmal response to intermittent photic stimulation (IPS) at baseline were randomized in a double-blind, 4-period cross-over study examining single doses of 17.5 and 52.5 mg PF-06372865, 2 mg lorazepam (active control), and placebo. Standardized photosensitivity ranges (SPRs) to IPS were recorded at screening, predose, and 1, 2, 4, and 6 hours postdose. The primary endpoint was the average least squares mean change in the SPR in the participant's most sensitive eye condition, across all time points. RESULTS: Both doses of PF-06372865 produced a marked and statistically significant mean reduction in SPR compared to placebo, which was similar in degree to lorazepam. There was complete suppression of SPR in 6/7 participants following PF-06372865 or lorazepam administration. PF-06372865 was safe and well-tolerated. CONCLUSION: PF-06372865 demonstrated highly robust efficacy. This demonstrates anticonvulsant activity of a novel α2/3/5-subtype selective GABAA PAM in humans. Further study of the antiepileptic properties of PF-06372865 is warranted. CLINICALTRIALSGOV IDENTIFIER: NCT02564029. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that for people with a stable photoparoxysmal response to intermittent photic stimulation, PF-06372865 reduces the SPR.

An 8-Week, Randomized, Phase 2, Double-Blind, Sequential Parallel-Group Comparison Study of Two Dose Levels of the GABAA Positive Allosteric Modulator PF-06372865 Compared With Placebo as an Adjunctive Treatment in Outpatients With Inadequate Response to Standard of Care for Generalized Anxiety Disorder.

BACKGROUND: Generalized anxiety disorder (GAD) is a common psychiatric disorder, but many patients experience only partial relief of symptoms with existing therapies. Benzodiazepines are effective in many cases but are limited by a number of significant adverse effects. PF-06372865 is a subtype-selective gamma-aminobutyric acid A (GABAA)-positive allosteric modulator lacking in functional activity at alpha 1-containing receptors that are believed to mediate many of these adverse effects. METHODS: PF-06372865 was evaluated as an adjunct to current GAD treatment in a double-blind, placebo-controlled, sequential parallel comparison study in patients with GAD who showed an incomplete response to current standard-of-care pharmacotherapy. A total of 90 subjects (of the planned 384) were randomized into the study before the decision to terminate the study. Two doses of PF-06372865 (2.5 mg twice daily and 7.5 mg twice daily) were compared with placebo. RESULTS: Neither dose of PF-06372865 differentiated from placebo on week 4 Hamilton Anxiety Inventory total (primary end point) or on the Sheehan Disability Scale total score (secondary end point). Adverse events including dizziness, headache, and somnolence were observed, and the 7.5 mg dose demonstrated some impairment on the Digit Symbol Substitution test and the Epworth Sleepiness Scale relative to placebo and the 2.5 mg dose. CONCLUSIONS: Factors contributing to the negative results include the limited sample size and failure to explore a broader range of doses.

Audio Recording for Independent Confirmation of Clinical Assessments in Generalized Anxiety Disorder.

Objective: The assessment of patients with generalized anxiety disorder (GAD) to deteremine whether a medication intervention is necessary is not always clear and might benefit from a second opinion. However, second opinions are time consuming, expensive, and not practical in most settings. We obtained independent, second opinion reviews of the primary clinician's assessment via audio-digital recording. Design: An audio-digital recording of key site-based assessments was used to generate site-independent "dual" reviews of the clinical presentation, symptom severity, and medication requirements of patients with GAD as part of the screening procedures for a clinical trial (ClinicalTrials.gov: NCT02310568). Results: Site-independent reviewers affirmed the diagnosis, symptom severity metrics, and treatment requirements of 90 moderately ill patients with GAD. The patients endorsed excessive worry that was hard to control and essentially all six of the associated DSM-IV-TR anxiety symptoms. The Hamilton Rating Scale for Anxiety scores revealed moderately severe anxiety with a high Pearson's correlation (r=0.852) between site-based and independent raters and minimal scoring discordance on each scale item. Based upon their independent reviews, these "second" opinions confirmed that these GAD patients warranted a new medication intervention. Thirty patients (33.3%) reported a previous history of a major depressive episode (MDE) and had significantly more depressive symptoms than patients without a history of MDE. Conclusion: The audio-digital recording method provides a useful second opinion that can affirm the need for a different treatment intervention in these anxious patients. A second live assessment would have required additional clinic time and added patient burden. The audio-digital recording method is less burdensome than live second opinion assessments and might have utility in both research and clinical practice settings.

A randomised, placebo-controlled clinical trial with the α2/3/5 subunit selective GABAA positive allosteric modulator PF-06372865 in patients with chronic low back pain.

The effect of PF-06372865, a subtype-selective positive allosteric modulator of the γ-aminobutyric acid type A (GABAA) receptor, on chronic low back pain was investigated in a randomised, placebo- and active-controlled phase 2 clinical trial. The parallel treatment group trial consisted of a 1-week single-blind placebo run in the phase, followed by 4-week double-blind treatment. Patients were randomised to receive either PF-06372865, naproxen, or placebo twice a day for 4 weeks. The primary end point was the numerical rating score of low back pain intensity after 4 weeks of active treatment. Secondary end points included the Roland Morris Disability Questionnaire and the Hopkins Verbal Learning Test-Revised. The trial had predefined decision rules based on the probability that PF-06372865 was better than placebo. The study was stopped at the interim analysis for futility. At this time, a total of 222 patients were randomised and the mean PF-06372865 4-week response on the low back pain intensity was 0.16 units higher (worse) than placebo (90% confidence interval -0.28 to 0.60). There were small, statistically significant reductions in the delayed recall test score with PF-06372865, as measured by Hopkins Verbal Learning Test-Revised. The effects of naproxen were in line with expectations. PF-06372865 was well tolerated. The most common treatment-related adverse events in the PF-06372865 arm were somnolence (5 mild and 4 moderate), dizziness (2 mild and 3 moderate), and nausea (2 mild). Although the reason for the lack of analgesic effect is not completely clear, it may be a result of not achieving sufficient receptor occupancy to drive efficacy.

Phase 1 clinical study of an embryonic stem cell-derived retinal pigment epithelium patch in age-related macular degeneration.

Age-related macular degeneration (AMD) remains a major cause of blindness, with dysfunction and loss of retinal pigment epithelium (RPE) central to disease progression. We engineered an RPE patch comprising a fully differentiated, human embryonic stem cell (hESC)-derived RPE monolayer on a coated, synthetic basement membrane. We delivered the patch, using a purpose-designed microsurgical tool, into the subretinal space of one eye in each of two patients with severe exudative AMD. Primary endpoints were incidence and severity of adverse events and proportion of subjects with improved best-corrected visual acuity of 15 letters or more. We report successful delivery and survival of the RPE patch by biomicroscopy and optical coherence tomography, and a visual acuity gain of 29 and 21 letters in the two patients, respectively, over 12 months. Only local immunosuppression was used long-term. We also present the preclinical surgical, cell safety and tumorigenicity studies leading to trial approval. This work supports the feasibility and safety of hESC-RPE patch transplantation as a regenerative strategy for AMD.

Pharmacology in translation: the preclinical and early clinical profile of the novel α2/3 functionally selective GABAA receptor positive allosteric modulator PF-06372865.

BACKGROUND AND PURPOSE: Benzodiazepines, non-selective positive allosteric modulators (PAMs) of GABAA receptors, have significant side effects that limit their clinical utility. As many of these side effects are mediated by the α1 subunit, there has been a concerted effort to develop α2/3 subtype-selective PAMs. EXPERIMENTAL APPROACH: In vitro screening assays were used to identify molecules with functional selectivity for receptors containing α2/3 subunits over those containing α1 subunits. In vivo receptor occupancy (RO) was conducted, prior to confirmation of in vivo α2/3 and α1 pharmacology through quantitative EEG (qEEG) beta frequency and zolpidem drug discrimination in rats respectively. PF-06372865 was then progressed to Phase 1 clinical trials. KEY RESULTS: PF-06372865 exhibited functional selectivity for those receptors containing α2/3/5 subunits, with significant positive allosteric modulation (90-140%) but negligible activity (≤20%) at GABAA receptors containing α1 subunits. PF-06372865 exhibited concentration-dependent occupancy of GABAA receptors in preclinical species. There was an occupancy-dependent increase in qEEG beta frequency and no generalization to a GABAA α1 cue in the drug-discrimination assay, clearly demonstrating the lack of modulation at the GABAA receptors containing an α1 subtype. In a Phase 1 single ascending dose study in healthy volunteers, evaluation of the pharmacodynamics of PF-06372865 demonstrated a robust increase in saccadic peak velocity (a marker of α2/3 pharmacology), increases in beta frequency qEEG and a slight saturating increase in body sway. CONCLUSIONS AND IMPLICATIONS: PF-06372865 has a unique clinical pharmacology profile and a highly predictive translational data package from preclinical species to the clinical setting.

Learning to identify CNS drug action and efficacy using multistudy fMRI data.

The therapeutic effects of centrally acting pharmaceuticals can manifest gradually and unreliably in patients, making the drug discovery process slow and expensive. Biological markers providing early evidence for clinical efficacy could help prioritize development of the more promising drug candidates. A potential source of such markers is functional magnetic resonance imaging (fMRI), a noninvasive imaging technique that can complement molecular imaging. fMRI has been used to characterize how drugs cause changes in brain activity. However, variation in study protocols and analysis techniques has made it difficult to identify consistent associations between subtle modulations of brain activity and clinical efficacy. We present and validate a general protocol for functional imaging-based assessment of drug activity in the central nervous system. The protocol uses machine learning methods and data from multiple published studies to identify reliable associations between drug-related activity modulations and drug efficacy, which can then be used to assess new data. A proof-of-concept version of this approach was developed and is shown here for analgesics (pain medication), and validated with eight separate studies of analgesic compounds. Our results show that the systematic integration of multistudy data permits the generalized inferences required for drug discovery. Multistudy integrative strategies of this type could help optimize the drug discovery and validation pipeline.

Characterization, optimisation and process robustness of a co-processed mannitol for the development of orally disintegrating tablets.

This is a study to fully assess a commercially available co-processed mannitol for its usefulness as an off-the-shelf excipient for developing orally disintegrating tablets (ODTs) by direct compression on a pilot scale (up to 4 kg). This work encompassed material characterization, formulation optimisation and process robustness. Overall, this co-processed mannitol possessed favourable physical attributes including low hygroscopicity and compactibility. Two design-of-experiments (DoEs) were used to screen and optimise the placebo formulation. Xylitol and crospovidone concentrations were found to have the most significant impact on disintegration time (p < 0.05). Higher xylitol concentrations retarded disintegration. Avicel PH102 promoted faster disintegration than PH101, at higher levels of xylitol. Without xylitol, higher crospovidone concentrations yielded faster disintegration and reduced tablet friability. Lubrication sensitivity studies were later conducted at two fill loads, three levels for lubricant concentration and number of blend rotations. Even at 75% fill load, the design space plot showed that 1.5% lubricant and 300 blend revolutions were sufficient to manufacture ODTs with ≤ 0.1% friability and disintegrated within 15 s. This study also describes results using a modified disintegration method based on the texture analyzer as an alternative to the USP method.

Raman mapping of low-content active-ingredient pharmaceutical formulations. part II: statistically optimized sampling for detection of less than 1% of an active pharmaceutical ingredient.

Several tablets are prepared with two forms of an active pharmaceutical ingredient (API) of which one (less than 1% w/w) is considered undesirable. The presence of this component is tested for by Raman microscopy in a series of mapping experiments. These experiments are conducted with a statistically based sampling routine in which the number of spectra to collect across the whole surface of a tablet is set so as to theoretically ensure spectral detection of the low-concentration form. Such experiments are then repeated a number of times to achieve approximately 95% confidence that the strictly limited number of sampling points suffice to detect the low-concentration form and that Raman microscopy is technically a reliable method for analytical analysis of this type.

Induced hepatic fibrosis in rats: hepatic steatosis, macromolecule content, perfusion parameters, and their correlations--preliminary MR imaging in rats.

PURPOSE: To prospectively evaluate magnetic resonance (MR) imaging for the characterization of liver fibrosis by estimating fat and extracellular matrix content and hepatic perfusion parameters in CCl(4)-treated rats. MATERIALS AND METHODS: The animal research protocol was approved by the Institutional Animal Care and Use Committee. Fifty-two rats (38 treated, 14 control) were included. A CCl(4) mixture was injected three times per week for 2-16 weeks. Fat-to-water ratios (FWRs) were calculated. Images were obtained with 12 saturation offset frequencies; magnetization transfer ratios (MTRs) were calculated. Distribution volume (DV), mean transit time (MTT), and portal fraction (PF) of blood inflow were calculated. For pairwise group comparisons, an unequal two-tailed Student t test was used. For pairwise correlations between variables, Pearson correlation coefficients were calculated. For multiple pairwise comparisons, Bonferroni correction was performed by adjusting the significance level (alpha). RESULTS: FWR and DV were correlated with CCl(4) treatment duration from 0 through 8 weeks (r = 0.658, P < .001 and r = -0.664, P < .001, respectively; alpha = .010). PF and MTT were correlated with CCl(4) treatment duration from 0 through 16 weeks (r = -0.483, P = .002 and r = 0.414, P = .008, respectively; alpha = .010). DV was inversely correlated with FWR over the same period (r = -0.581, P < .001; alpha = .007). Fibrotic rats without cirrhosis had a higher FWR and lower DV and PF (P < .001, P < .001, and P = .004, respectively; alpha = .017) than control rats, and lower MTR, DV, and MTT (P = .014, .001, and .010, respectively; alpha = .017) than cirrhotic rats. Cirrhotic rats had a higher FWR and a lower PF (P < .001, alpha = .017) than control rats. CONCLUSION: Magnetization transfer contrast is not a specific indicator of increased fibrosis in diseased liver; steatosis may influence some perfusion parameters.