Totality of evidence of the effectiveness of repurposed therapies for COVID-19: Can we use real-world studies alongside randomized controlled trials?

Rapid and robust strategies to evaluate the efficacy and effectiveness of novel and existing pharmacotherapeutic interventions (repurposed treatments) in future pandemics are required. Observational "real-world studies" (RWS) can report more quickly than randomized controlled trials (RCTs) and would have value were they to yield reliable results. Both RCTs and RWS were deployed during the coronavirus disease 2019 (COVID-19) pandemic. Comparing results between them offers a unique opportunity to determine the potential value and contribution of each. A learning review of these parallel evidence channels in COVID-19, based on quantitative modeling, can help improve speed and reliability in the evaluation of repurposed therapeutics in a future pandemic. Analysis of all-cause mortality data from 249 observational RWS and RCTs across eight treatment regimens for COVID-19 showed that RWS yield more heterogeneous results, and generally overestimate the effect size subsequently seen in RCTs. This is explained in part by a few study factors: the presence of RWS that are imbalanced for age, gender, and disease severity, and those reporting mortality at 2 weeks or less. Smaller studies of either type contributed negligibly. Analysis of evidence generated sequentially during the pandemic indicated that larger RCTs drive our ability to make conclusive decisions regarding clinical benefit of each treatment, with limited inference drawn from RWS. These results suggest that when evaluating therapies in future pandemics, (1) large RCTs, especially platform studies, be deployed early; (2) any RWS should be large and should have adequate matching of known confounders and long follow-up; (3) reporting standards and data standards for primary endpoints, explanatory factors, and key subgroups should be improved; in addition, (4) appropriate incentives should be in place to enable access to patient-level data; and (5) an overall aggregate view of all available results should be available at any given time.

Meta-Analyses of Clinical Efficacy of Risankizumab and Adalimumab in Chronic Plaque Psoriasis: Supporting Evidence of Risankizumab Superiority.

Risankizumab, an anti-interleukin-23 monoclonal antibody, achieved significantly (P < 0.001) greater Psoriasis Area and Severity Index (PASI) and static Physician Global Assessment (sPGA) clear or almost clear (0/1) responses than adalimumab in a phase III trial in patients with moderate-to-severe psoriasis. Meta-analyses of the PASI 50, PASI 75, PASI 90, PASI 100, and sPGA0/1 responses after 16 weeks of treatment from eight (three for risankizumab and five for adalimumab) randomized, placebo-controlled trials were conducted to estimate the efficacy difference between risankizumab and adalimumab. For PASI 75, PASI 90, PASI 100, and sPGA0/1 responses, the estimated effect differences (95% confidence interval) between risankizumab and adalimumab were 15.2% (10.1%, 20.4%), 23.7% (15.7%, 31.2%), 20.8% (13.0%, 28.7%), and 20.1% (13.7%, 26.1%), respectively. These results were consistent with the observed efficacy difference from the head-to-head phase III trial, which was not included in the meta-analyses, providing independent, confirmatory evidence of the superior efficacy of risankizumab compared with adalimumab for treatment of moderate-to-severe psoriasis.

Short-Term Efficacy Reliably Predicts Long-Term Clinical Benefit in Rheumatoid Arthritis Clinical Trials as Demonstrated by Model-Based Meta-Analysis.

The objective of this study was to assess the relationship between short-term and long-term treatment effects measured by the American College of Rheumatology (ACR) 50 responses and to assess the feasibility of predicting 6-month efficacy from short-term data. A rheumatoid arthritis (RA) database was constructed from 68 reported trials. We focused on the relationship between 3- and 6-month ACR50 treatment effects and developed a generalized nonlinear model to quantify the relationship and test the impact of covariates. The ΔACR50 at 6 months strongly correlated with that at 3 months, moderately correlated with that at 2 months, and only weakly correlated with results obtained at <2 months. A scaling factor that reflected the ratio of 6- to 3-month treatment effects was estimated to be 0.997, suggesting that the treatment effects at 3 months are approaching a "plateau." Drug classes, baseline Disease Activity Score in 28 Joints, and the magnitude of control arm response did not show significant impacts on the scaling factor. This work quantitatively supports the empirical clinical development paradigm of using 3-month efficacy data to predict long-term efficacy and to inform the probability of clinical success based on early efficacy readout.

A model-based dose-response meta-analysis of ocular hypotensive agents as a drug development tool to evaluate new therapies in glaucoma.

PURPOSE: To characterize dose and response for intraocular pressure (IOP) reduction and incidence of hyperemia using a model-based meta-analysis of IOP-lowering monotherapy studies to evaluate new ocular antihypertensive therapies for glaucoma. METHODS: Published randomized controlled trials, regulatory documents, and sponsor reports of IOP-lowering monotherapies were used to develop dose-response models to characterize efficacy (IOP change from baseline) and safety (incidence of hyperemia) profiles. RESULTS: The meta-analysis for efficacy included 31 trials with 6,516 patients receiving bimatoprost, latanoprost, travoprost, timolol, or placebo. Estimated IOP reduction with placebo was -2.01 mmHg. Maximal IOP reduction was similar among the prostaglandin analogs (estimate, -6.27 mmHg; baseline, 25 mmHg). Estimated median effective IOP-lowering dose (ED50) was 0.002%, 0.00098%, and 0.00063% daily with bimatoprost, latanoprost, and travoprost, respectively. The hyperemia (safety) analysis included 25 trials with 6,244 patients. Typical maximal estimated difference between drug and placebo was 43%, and estimated ED50 of 0.011%, 0.014%, and 0.0015% daily for bimatoprost, latanoprost, and travoprost, respectively. Latanoprost treatment was predicted to incur the lowest rate of hyperemia of the prostaglandins, for equivalent IOP reduction. CONCLUSIONS: Model-based meta-analyses for IOP reduction and incidence of hyperemia among prostaglandin analogs are well described by maximal efficacy models and can provide a useful methodology for evaluating glaucoma therapies.

Time course of bone mineral density changes with denosumab compared with other drugs in postmenopausal osteoporosis: a dose-response-based meta-analysis.

OBJECTIVE: Our objective was to compare the time course of bone mineral density (BMD) changes at the lumbar spine (LS) and total hip (TH) in postmenopausal women during treatment with denosumab, bisphosphonates, selective estrogen receptor modulators, PTH, or calcitonin. DATA SOURCES AND STUDY SELECTION: Data were extracted from 142 randomized controlled trials for prevention or treatment of postmenopausal osteoporosis representing over 113,000 women. DATA EXTRACTION AND DATA SYNTHESIS: The percent change from baseline in BMD was analyzed using a nonlinear least-squares random-effects meta-regression analysis. The dose-response relationship of BMD changes was well characterized by a maximal effect (EMax) model with a different EMax for LS and TH for each drug class. The ratio of LS and TH BMD changes was significantly different across the different drug classes. The time course of BMD changes was well characterized by an exponential onset with a different rate for LS and TH for each drug class. The dose-response relationship for denosumab showed that the approved dosing regimen of 60 mg every 6 months resulted in maximal BMD changes. CONCLUSION: This exploratory analysis shows that 3 years of treatment with denosumab resulted in bigger changes in LS and TH BMD compared with 3 years of treatment with 10 mg/d oral alendronate, 5 mg/y i.v. zoledronic acid, 5 mg/d oral risedronate, 150 mg/mo oral ibandronate, 3 mg i.v. ibandronate every 3 months, 60 mg/d oral raloxifene, and 200 IU/d calcitonin. Treatment with PTH resulted in larger changes in LS BMD compared with denosumab; however, denosumab treatment provided larger changes in TH BMD.

Similar relationship between the time course of bone mineral density improvement and vertebral fracture risk reduction with denosumab treatment in postmenopausal osteoporosis and prostate cancer patients on androgen deprivation therapy.

Denosumab has received approval in many countries and indications include treating women with postmenopausal osteoporosis (PMO) at increased or high risk for fracture and men at high risk for fracture receiving androgen deprivation therapy (ADT) for non-metastatic prostate cancer. Increases in total hip bone mineral density (BMD) with denosumab explained a large percentage of new vertebral fracture risk reduction in women with PMO; however, this effect has not been studied in men with prostate cancer receiving ADT. We compared the relationship between the time course of BMD changes and new vertebral fracture risk reduction with denosumab in women with PMO and men with prostate cancer. After adjusting for different baseline hazards, a significant and similar relationship between time course of total hip and lumbar spine BMD changes and new vertebral fracture risk was observed in both patient populations. Time course of total hip BMD changes with denosumab was the best predictor for changes in fracture risk and explained 88% of the new vertebral fracture risk reduction in women with PMO and 91% in men with prostate cancer. Therefore, total hip BMD is a useful surrogate to measure the clinical impact of denosumab on fracture risk reduction in both patient populations.

Modeling the onset and offset of dental pain relief by ibuprofen.

Onset and offset of dental pain relief by ibuprofen following third molar extraction were modeled in a randomized, double-blind, placebo-controlled, parallel-group, 8-hour study of patients receiving either a novel effervescent ibuprofen tablet (400 mg; N = 30), standard ibuprofen tablets (Nurofen(®) 2 × 200 mg; N = 22), or placebo (N = 37). An Emax model was fit to pain relief scores. Linear hazard models were used to analyze the time to first perceptible relief (TFPR), the time to meaningful pain relief (TMPR), and time to remedication (REMD). Nomograms were created to correlate TFPR, TMPR, and REMD with different ibuprofen pharmacokinetic profiles. Effervescent ibuprofen was absorbed rapidly with 95% completion within 15 minutes. Maximum pain relief score by ibuprofen was 1.8 units greater than placebo, with an EC50 (effect-site) for ibuprofen concentration of 10.2 µg·mL(-1). The likelihood to achieve TFPR and TMPR was doubled for every 10 µg·mL(-1) increase in ibuprofen plasma concentration. REMD risk decreased 40-fold as the categorical pain relief score increased from 0 to 3. Rapid absorption of ibuprofen effervescent resulted in an earlier TFPR and TMPR, and a lower REMD rate than standard ibuprofen. The nomograms may be useful in predicting the onset and offset of new faster acting ibuprofen formulations, based on pharmacokinetic profiles.

Discovery of novel hepatoselective HMG-CoA reductase inhibitors for treating hypercholesterolemia: a bench-to-bedside case study on tissue selective drug distribution.

The design of drugs with selective tissue distribution can be an effective strategy for enhancing efficacy and safety, but understanding the translation of preclinical tissue distribution data to the clinic remains an important challenge. As part of a discovery program to identify next generation liver selective HMG-CoA reductase inhibitors we report the identification of (3R,5R)-7-(4-((3-fluorobenzyl)carbamoyl)-5-cyclopropyl-2-(4-fluorophenyl)-1H-imidazol-1-yl)-3,5-dihydroxyheptanoic acid (26) as a candidate for treating hypercholesterlemia. Clinical evaluation of 26 (PF-03491165), as well as the previously reported 2 (PF-03052334), provided an opportunity for a case study comparison of the preclinical and clinical pharmacokinetics as well as pharmacodynamics of tissue targeted HMG-CoA reductase inhibitors.

Parathyroid hormone (1-34)-coated microneedle patch system: clinical pharmacokinetics and pharmacodynamics for treatment of osteoporosis.

OBJECTIVES: To evaluate the clinical PK/PD of PTH(1-34) delivered by a novel transdermal drug-coated microneedle patch system (ZP-PTH) for the treatment of osteoporosis. METHODS: Phase 1 PK studies evaluated the effect of site of administration, patch wear time and dose in normal volunteers, ages 40-85 yrs. Phase 2 was conducted in post-menopausal women with osteoporosis to determine the patch dose response compared to placebo patch and FORTEO® injection. RESULTS: Phase 1 ZP-PTH patch delivery demonstrated a rapid PTH plasma pulse profile with T(max) 3 times shorter and apparent T(1/2) 2 times shorter than FORTEO®. In Phase 2, ZP-PTH 20, 30 and 40 µg doses showed a proportional increase in plasma PTH AUC. Inter-subject and intra-subject AUC variability was similar for all patch doses and comparable to injection. All patch doses produced a significant increase in spine bone mineral density. Unexpectedly, ZP-PTH also produced an early increase in hip bone mineral density, an effect not observed with the injection. CONCLUSIONS: These studies suggest that this novel ZP-PTH patch system can deliver a consistent and therapeutically relevant PTH PK profile. Based on encouraging Phase 2 safety and efficacy data, the program is advancing into a pivotal Phase 3 clinical study.

Model-based development of gemcabene, a new lipid-altering agent.

The purpose of this study was to evaluate the value of model-based, quantitative decision making during the development of gemcabene, a novel lipid-altering agent. The decisions were driven by a model of the likely clinical profile of gemcabene in comparison with its competitors, such as 3-hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), the cholesterol absorption inhibitor ezetimibe, and their combination. Dose-response models were developed for the lipid effects (low-density lipoprotein cholesterol [LDL-C] and high-density lipoprotein cholesterol); adverse effects, such as persistent alanine aminotransferase elevation and myalgia; tolerability issues, such as headache; and risk reduction for coronary artery disease-related events for 5 statins, ezetimibe, gemcabene, and their combinations. The integrated model was based on the joint analysis of publicly available summary-level data and proprietary patient-level data and included information from almost 10,000 patients. The model was made available and accessible to the development team by using the Pharsight Drug Model Explorer model visualization technology. The modeling greatly enhanced the understanding of the clinical profile of gemcabene when given alone or in combination with a statin. The interaction between statins and gemcabene for the LDL-C lowering effect was found to be significantly different from the interaction between statins and ezetimibe. Ezetimibe was found to have a pharmacological-independent interaction resulting in additional LDL-C lowering over the entire statin dose range. The gemcabene interaction was found to be less than independent, resulting in almost no additional LDL-C lowering at high-statin doses, although the drug has a significant LDL-C effect when administered alone or in combination with a low dose of a statin. The quick availability of the model after completion of the first phase II trial in the target patient population and the ability of the team to explore the potential clinical efficacy and safety of gemcabene in comparison with alternative treatment options facilitated a quick decision to stop development.

The use of clinical trial simulation to support dose selection: application to development of a new treatment for chronic neuropathic pain.

PURPOSE: Pregabalin is being evaluated for the treatment of neuropathic pain. Two phase 2 studies were simulated to determine how precisely the dose that caused a one-point reduction in the pain score could be estimated. The likelihood of demonstrating at least a one-point change for each available dose strength was also calculated. METHODS: A pharmacokinetic-pharmacodynamic (PK/PD) model relating pain relief to gabapentin plasma concentrations was derived from a phase 3 study. The PK component of the model was modified to reflect pregabalin PK. The PD component was modified by scaling the gabapentin concentration-effect relationship to reflect pregabalin potency, which was based on preclincal data. Uncertainty about the potency difference and the steepness of the concentration-response slope necessitated simulating a distribution of outcomes for a series of PK/PD models. RESULTS: Analysis of the simulated data suggested that after accounting for the uncertainty, there was an 80% chance that the dose defining the clinical feature was within 45% of the true value. The likelihood of estimating a dose that was within an acceptable predefined precision range relative to a known value approximated 60%. The minimum dose that should be studied to have a reasonable chance of estimating the dose that caused a one-point change was 300 mg. CONCLUSIONS: Doses that identify predefined response may be imprecisely estimated, suggesting that replication of a similar outcome may be elusive in a confirmatory study. Quantification of this precision provides a rationale for phase 2 trial design and dose selection for confirmatory studies.

Pharmacokinetics of melagatran and the effect on ex vivo coagulation time in orthopaedic surgery patients receiving subcutaneous melagatran and oral ximelagatran: a population model analysis.

OBJECTIVE: Ximelagatran, an oral direct thrombin inhibitor, is rapidly bioconverted to melagatran, its active form. The objective of this population analysis was to characterise the pharmacokinetics of melagatran and its effect on activated partial thromboplastin time (APTT), an ex vivo measure of coagulation time, in orthopaedic surgery patients sequentially receiving subcutaneous melagatran and oral ximelagatran as prophylaxis for venous thromboembolism. To support the design of a pivotal dose-finding study, the impact of individualised dosage based on bodyweight and calculated creatinine clearance was examined. DESIGN AND METHODS: Pooled data obtained in three small dose-guiding studies were analysed. The patients received twice-daily administration, with either subcutaneous melagatran alone or a sequential regimen of subcutaneous melagatran followed by oral ximelagatran, for 8-11 days starting just before initiation of surgery. Nonlinear mixed-effects modelling was used to evaluate rich data of melagatran pharmacokinetics (3326 observations) and the pharmacodynamic effect on APTT (2319 observations) in samples from 216 patients collected in the three dose-guiding trials. The pharmacokinetic and pharmacodynamic models were validated using sparse data collected in a subgroup of 319 patients enrolled in the pivotal dose-finding trial. The impact of individualised dosage on pharmacokinetic and pharmacodynamic variability was evaluated by simulations of the pharmacokinetic-pharmacodynamic model. RESULTS: The pharmacokinetics of melagatran were well described by a one-compartment model with first-order absorption after both subcutaneous melagatran and oral ximelagatran. Melagatran clearance was correlated with renal function, assessed as calculated creatinine clearance. The median population clearance (creatinine clearance 70 mL/min) was 5.3 and 22.9 L/h for the subcutaneous and oral formulations, respectively. The bioavailability of melagatran after oral ximelagatran relative to subcutaneous melagatran was 23%. The volume of distribution was influenced by bodyweight. For a patient with a bodyweight of 75kg, the median population estimates were 15.5 and 159L for the subcutaneous and oral formulations, respectively. The relationship between APTT and melagatran plasma concentration was well described by a power function, with a steeper slope during and early after surgery but no influence by any covariates. Simulations demonstrated that individualised dosage based on creatinine clearance or bodyweight had no clinically relevant impact on the variability in melagatran pharmacokinetics or on the effect on APTT. CONCLUSIONS: The relatively low impact of individualised dosage on the pharmacokinetic and pharmacodynamic variability of melagatran supported the use of a fixed-dose regimen in the studied population of orthopaedic surgery patients, including those with mild to moderate renal impairment.