Results on patient-reported outcomes are underreported in summaries of product characteristics for new drugs.

BACKGROUND: Summaries of product characteristics (SmPCs) are regulatory documents published upon drug approval. They should report all relevant study data and advise how to use drugs safely and effectively. Patient-reported outcomes (PROs) are increasingly used in clinical trials to incorporate the patient perspective-SmPCs should thus adequately report PROs. In Germany, new drugs undergo mandatory early benefit assessment. Pharmaceutical companies submit dossiers containing all evidence; the subsequent dossier assessments focus on patient-relevant outcomes and comprehensively report PROs. OBJECTIVE: The primary aim was to investigate to what extent PROs recorded as outcomes in clinical trials of new drugs are reported in SmPCs. METHODS: We analysed dossier assessments with randomized controlled trials (RCTs) of new drugs entering the market between 01/2014 and 07/2018 and the corresponding SmPCs, and compared PRO reporting in both document types. For this purpose, we evaluated dossier assessment characteristics (e.g. drug name, indication, disease category) and study characteristics (e.g. evaluable PROs available?). PROs were divided into symptoms and health-related quality of life (HRQoL). SmPCs were screened to identify RCTs. We conducted 3 main evaluation steps: (1) Did the RCT included in the dossier assessment contain evaluable PROs? (2) If yes, was the RCT included in the SmPC? (3) If yes, were the PROs reported in the SmPC? Results are presented descriptively. RESULTS: 88 dossier assessments including 143 RCTs on 72 drugs were considered: 109 (76.2%) RCTs included evaluable PROs, of which 89 were included in SmPCs. 38 RCTs (42.7%) investigated oncologics, 18 (20.2%) anti-infectives, and 33 (37.1%) other drugs. The RCTs considered symptoms more often than HRQoL (82 vs. 66 RCTs). In SmPCs, PROs were reported for 41 RCTs (46.1%), with a slightly higher reporting rate for RCTs considering HRQoL (43.9%) than for RCTs considering symptoms (41.5%). In oncologic indications, PROs were reported for 36.7% of RCTs considering HRQoL and 33.3% of RCTs considering symptoms. In infectious diseases, the rates were 21.4% (symptoms) and 0% (HRQoL), and for other diseases about 60% (symptoms) to 70% (HRQoL). CONCLUSION: Even though a large amount of PRO data on new drugs is available from clinical trials included in SmPCs, the corresponding results are underreported.

A Novel Study Design Using Continuous Intravenous and Intraduodenal Infusions of Midazolam and Voriconazole for Mechanistic Quantitative Assessment of Hepatic and Intestinal CYP3A Inhibition.

The extent of a drug-drug interaction (DDI) mediated by cytochrome P450 (CYP) 3A inhibitors is highly variable during a dosing interval, as it depends on the temporal course of victim and perpetrator drug concentrations at intestinal and hepatic CYP3A expression sites. Capturing the time course of inhibition is therefore difficult using standard DDI studies assessing changes in area under the curve; thus, a novel design was developed. In a 4-period changeover pilot study, 6 healthy men received intraduodenal or intravenous infusions of the CYP3A substrate midazolam (MDZ) at a rate of 0.26 mg/h for 24 hours. This was combined with intraduodenal or intravenous infusion of the CYP3A inhibitor voriconazole (VRZ), administered at rates of 7.5 mg/h from 8 to 16 hours and of 15 mg/h from 16 to 24 hours, after starting midazolam administration. Plasma and urine concentrations of VRZ, MDZ, and its major metabolites were quantified by liquid chromatography-tandem mass spectrometry and analyzed by semiphysiological population pharmacokinetic nonlinear mixed-effects modeling. A model including mechanism-based inactivation of the metabolizing enzymes (maximum inactivation rate constant kinact , 2.83 h-1 ; dissociation rate constant KI , 9.33 µM) described the pharmacokinetics of VRZ well. By introducing competitive inhibition by VRZ on primary and secondary MDZ metabolism, concentration-time profiles, MDZ and its metabolites were captured appropriately. The model provides estimates of local concentrations of substrate and inhibitor at the major CYP3A expression sites and thus of the respective dynamic extent of inhibition. A combination of intravenous and intraduodenal infusions of inhibitors and substrates has the potential to provide a more accurate assessment of DDIs occurring in both gut wall and liver.

Sorafenib and everolimus in patients with advanced solid tumors and KRAS-mutated NSCLC: A phase I trial with early pharmacodynamic FDG-PET assessment.

BACKGROUND: Treatment of patients with solid tumors and KRAS mutations remains disappointing. One option is the combined inhibition of pathways involved in RAF-MEK-ERK and PI3K-AKT-mTOR. METHODS: Patients with relapsed solid tumors were treated with escalating doses of everolimus (E) 2.5-10.0 mg/d in a 14-day run-in phase followed by combination therapy with sorafenib (S) 800 mg/d from day 15. KRAS mutational status was assessed retrospectively in the escalation phase. Extension phase included KRAS-mutated non-small-cell lung cancer (NSCLC) only. Pharmacokinetic analyses were accompanied by pharmacodynamics assessment of E by FDG-PET. Efficacy was assessed by CT scans every 6 weeks of combination. RESULTS: Of 31 evaluable patients, 15 had KRAS mutation, 4 patients were negative for KRAS mutation, and the KRAS status remained unknown in 12 patients. Dose-limiting toxicity (DLT) was not reached. The maximum tolerated dose (MTD) was defined as 7.5 mg/d E + 800 mg/d S due to toxicities at previous dose level (10 mg/d E + 800 mg/d S) including leucopenia/thrombopenia III° and pneumonia III° occurring after the DLT interval. The metabolic response rate in FDG-PET was 17% on day 5 and 20% on day 14. No patient reached partial response in CT scan. Median progression free survival (PFS) and overall survival (OS) were 3.25 and 5.85 months, respectively. CONCLUSIONS: Treatment of patients with relapsed solid tumors with 7.5 mg/d E and 800 mg/d S is safe and feasible. Early metabolic response in FDG-PET was not confirmed in CT scan several weeks later. The combination of S and E is obviously not sufficient to induce durable responses in patients with KRAS-mutant solid tumors.

A semiphysiological population pharmacokinetic model for dynamic inhibition of liver and gut wall cytochrome P450 3A by voriconazole.

BACKGROUND: Accurate predictions of cytochrome P450 (CYP) 3A-mediated drug-drug interactions (DDIs) account for dynamic changes of CYP3A activity at both major expression sites (liver and gut wall) by considering the full pharmacokinetic profile of the perpetrator and the substrate. Physiological-based in vitro-in vivo extrapolation models have become of increasing interest. However, due to discrepancies between the predicted and observed magnitude of DDIs, the role of models fully based on in vivo data is still essential. OBJECTIVE: The primary objective of this study was to develop a coupled dynamic model for the interaction of the CYP3A inhibitor voriconazole and the prototypical CYP3A substrate midazolam. METHODS: Raw concentration data were obtained from a DDI study. Ten subjects were given either no pretreatment (control) or voriconazole twice daily orally. Midazolam was given either intravenously or orally after the last voriconazole dose and during control phases. Data analysis was performed by the population pharmacokinetic approach using non-linear mixed effects modelling (NONMEM 7.2.0). Model evaluation was performed using visual predictive checks and bootstrap analysis. RESULTS: A semiphysiological model was able to describe the pharmacokinetics of midazolam, its major metabolite and voriconazole simultaneously. By considering the temporal disposition of all three substances in the liver and gut wall, a time-varying CYP3A inhibition process was implemented. Only the incorporation of hypothetical enzyme site compartments resulted in an adequate fit, suggesting a sustained inhibitory effect through accumulation. Novel key features of this analysis are the identification of (1) an apparent sustained inhibitory effect by voriconazole due to a proposed quasi accumulation at the enzyme site, (2) a significantly reduced inhibitory potency of intravenous voriconazole for oral substrates, (3) voriconazole as a likely uridine diphosphate glucuronosyltransferase (UGT) 2B inhibitor and (4) considerable sources of interindividual variability. CONCLUSION: The proposed semiphysiological modelling approach generated a mechanistic description of the complex DDI occurring at major CYP3A expression sites and thus may serve as a powerful tool to maximise information acquired from clinical DDI studies. The model has been shown to draw precise and accurate predictions. Therefore, simulations based on this kind of models may be used for various clinical scenarios to improve pharmacotherapy.