Utility and impact of quantitative pharmacology on dose selection and clinical development of immuno-oncology therapy

Immuno-oncology (IO) therapies have changed the cancer treatment landscape. Immune checkpoint inhibitors (ICIs) have improved overall survival in 20-40% of patients with malignancies that were previously refractory. Due to the uniqueness in biology, modalities and patient responses, drug development strategies for IO differed from that traditionally used for cytotoxic and target therapies in oncology, and quantitative pharmacology utilizing modeling approach can be applied in all phases of the development process. In this review, we used case studies to showcase how various modeling methodologies were applied from translational science and dose selection through to label change, using examples that included anti-programmed-death-1 (anti-PD-1), anti-programmed-death ligand-1 (anti-PD-L1), anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4), and anti-glucocorticoid-induced tumor necrosis factor receptor-related protein (anti-GITR) antibodies. How these approaches were utilized to support phase I-III dose selection, the design of phase III trials, and regulatory decisions on label change are discussed to illustrate development strategies. Model-based quantitative approaches have positively impacted IO drug development, and a better understanding of the biology and exposure-response relationship may benefit the development and optimization of new IO therapies.

Considerations for the development of guidance on dose level selection for developmental and reproductive toxicity studies

In 2022, the European Chemicals Agency issued advice on the selection of high dose levels for developmental and reproductive toxicity (DART) studies indicating that the highest dose tested should aim to induce clear evidence of reproductive toxicity without excessive toxicity and severe suffering in parental animals. In addition, a recent publication advocated that a 10% decrease in body weight gain should be replaced with a 10% decrease in bodyweight as a criterion for dose adequacy. Experts from the European Centre for Ecotoxicology and Toxicology of Chemicals evaluated these recent developments and their potential impact on study outcomes and interpretation and identified that the advice was not aligned with OECD test guidelines or with humane endpoints guidance. Furthermore, data analysis from DART studies indicated that a 10% decrease in maternal body weight during gestation equates to a 25% decrease in body weight gain, which differs from the consensus of experts at a 2010 ILSI/HESI workshop. Dose selection should be based on a biological approach that considers a range of other factors. Excessive dose levels that cause frank toxicity and overwhelm homeostasis should be avoided as they can give rise to effects that are not relevant to human health assessments.

Challenges, approaches and enablers: effectively triangulating towards dose selection in pediatric rare diseases

Dose selection is an integral part of a molecule's journey to become medicine. On top of typical challenges faced in dose selection for more common diseases, pediatric rare disease has additional unique challenges due to the combination of 'rare' and 'pediatric' populations. Using the central theme of maximizing 'relevant' information to overcome information paucity, dose selection strategy in pediatric rare diseases is discussed using a triangulation concept involving challenges, approaches and very importantly, enablers. Using actual examples, unique scenarios are discussed where specific enablers allowed certain approaches to be used to overcome the challenges. The continued need for model-informed drug development is also discussed using examples of where modeling and simulation tools have been successfully used in bridging available information to select pediatric doses in rare disease. Additionally, challenges with translation and associated dose selection of new modalities such as gene therapy in rare diseases are examined with the lens of continuous learning and knowledge development that will enable pediatric dose selection of these modalities with confidence.

Model-Informed Support of Dose Selection for Prophylactic Treatment with Dalcinonacog Alfa in Adult and Paediatric Hemophilia B Patients

INTRODUCTION

Dalcinonacog alfa (DalcA), a novel subcutaneously administered recombinant human factor IX (FIX) variant is being developed for adult and paediatric patients with hemophilia B (HB). DalcA has been shown to raise FIX to clinically meaningful levels in adults with HB. This work aimed to support dosing regimen selection in adults and perform first-in-paediatric dose extrapolations using a model-based pharmacokinetic (PK) approach.

METHODS

A population PK model was built using adult data from two clinical trials (NCT03186677, NCT03995784). With allometry in the model, clinical trial simulations were performed to study alternative dosing regimens in adults and children. Steady-state trough levels and the time-to-reach target were derived to inform dose selection.

RESULTS

Almost 90% of the adults were predicted to achieve desirable FIX levels, i.e. 10% FIX activity, following daily 100 IU/kg dosing, with 90% of the subjects reaching target within 1.6-7.1 days. No every-other-day regimen met the target. A dose of 125 IU/kg resulted in adequate FIX levels down to 6 years, whereas a 150 IU/kg dose was needed below 6 down to 2 years of age. For subjects down to 6 years that did not reach target with 125 IU/kg, a dose escalation to 150 IU/kg was appropriate. The children below 6 to 2 years were shown to need a dose escalation to 200 IU/kg if 150 IU/kg given daily was insufficient.

CONCLUSION

This study supported the adult dose selection for DalcA in the presence of sparse data and enabled first-in-paediatric dose selection to achieve FIX levels that reduce risk of spontaneous bleeds.

Pharmacokinetics and pharmacodynamics of polymyxin B and proposed dosing regimens in elderly patients with multi-drug-resistant Gram-negative bacterial infections

There are limited data on the pharmacokinetics (PK) and pharmacodynamics (PD) of polymyxin B in the elderly population. The objective of this study was to develop a population PK model of polymyxin B in elderly patients, determine factors that affect its PK parameters, and propose alternative dosing regimens. Critically ill elderly patients (age ≥65 years) who received intravenous polymyxin B for multi-drug-resistant Gram-negative bacterial infections were enrolled. A population PK model was developed using Phoenix NLME software. Monte Carlo simulations were performed to optimize regimens attaining the PK/PD target of AUC_24h/MIC >50 and target exposure of 50-100 mg‧h/L. Clinical efficacy and nephrotoxicity of polymyxin B treatment were also assessed. A total of 142 polymyxin B concentrations from 23 patients were available. A two-compartment model with first-order elimination was developed, and albumin was the significant covariate of PK parameters. However, albumin had only a slight effect on polymyxin B exposure. Simulation results indicated that two fixed regimens of 50 mg and 75 mg would be sufficient to reach the PK/PD targets when the minimum inhibitory concentrations was ≤0.5 mg/L. With the exception of 1.25 mg/kg for 58 kg, other weight-based regimens (1.25-1.5 mg/kg for 70 kg and 80 kg; twice daily) may result in at least 40% of predicted AUC_ss,24h >100 mg‧h/L. In conclusion, fixed maintenance dosing of 50 mg and 75 mg for polymyxin B may maximize efficacy while balancing nephrotoxicity concerns for elderly patients.

Exposure-response analyses for the MET inhibitor tepotinib including patients in the pivotal VISION trial: support for dosage recommendations

Purpose

Tepotinib is a highly selective MET inhibitor approved for treatment of non-small cell lung cancer (NSCLC) harboring METex14 skipping alterations. Analyses presented herein evaluated the relationship between tepotinib exposure, and efficacy and safety outcomes.

Methods

Exposure–efficacy analyses included data from an ongoing phase 2 study (VISION) investigating 500 mg/day tepotinib in NSCLC harboring METex14 skipping alterations. Efficacy endpoints included objective response, duration of response, and progression-free survival. Exposure–safety analyses included data from VISION, plus four completed studies in advanced solid tumors/hepatocellular carcinoma (30–1400 mg). Safety endpoints included edema, serum albumin, creatinine, amylase, lipase, alanine aminotransferase, aspartate aminotransferase, and QT interval corrected using Fridericia’s method (QTcF).

Results

Tepotinib exhibited flat exposure–efficacy relationships for all endpoints within the exposure range observed with 500 mg/day. Tepotinib also exhibited flat exposure–safety relationships for all endpoints within the exposure range observed with 30–1400 mg doses. Edema is the most frequently reported adverse event and the most frequent cause of tepotinib dose reductions and interruptions; however, the effect plateaued at low exposures. Concentration-QTc analyses using data from 30 to 1400 mg tepotinib resulted in the upper bounds of the 90% confidence interval being less than 10 ms for the mean exposures at the therapeutic (500 mg) and supratherapeutic (1000 mg) doses.

Conclusions

These analyses provide important quantitative pharmacologic support for benefit/risk assessment of the 500 mg/day dosage of tepotinib as being appropriate for the treatment of NSCLC harboring METex14 skipping alterations.

Registration Numbers

NCT01014936, NCT01832506, NCT01988493, NCT02115373, NCT02864992.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-022-04441-3.

Recommendations on dose level selection for repeat dose toxicity studies

Prior to registering and marketing any new pharmaceutical, (agro)chemical or food ingredient product manufacturers must, by law, generate data to ensure human safety. Safety testing requirements vary depending on sector, but generally repeat-dose testing in animals form the basis for human health risk assessments. Dose level selection is an important consideration when designing such studies, to ensure that exposure levels that lead to relevant hazards are identified. Advice on dose level selection is provided in test guidelines and allied guidance documents, but it is not well harmonised, particularly for selection of the highest dose tested. This paper further builds on concepts developed in a technical report by the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) which recommends pragmatic approaches to dose selection considering regulatory requirements, animal welfare and state of the art scientific approaches. Industry sectors have differing degrees of freedom to operate regarding dose level selection, depending on the purpose of the studies and the regulatory requirements/legislation, and this is reflected in the overall recommended approaches. An understanding of systemic exposure should be utilised where possible (e.g., through toxicokinetic approaches) and used together with apical endpoints from existing toxicity studies to guide more appropriate dose level selection. The highest dose should be limited to a reasonable level, causing minimal but evident toxicity to the test animals without significantly compromising their well-being. As the science of predictive human exposure further develops and matures, this will provide exciting and novel opportunities for more human-relevant approaches to dose level selection.

Opportunities and challenges related to saturation of toxicokinetic processes: Implications for risk assessment

Top dose selection for repeated dose animal studies has generally focused on identification of apical endpoints, use of the limit dose, or determination of a maximum tolerated dose (MTD). The intent is to optimize the ability of toxicity tests performed in a small number of animals to detect effects for hazard identification. An alternative approach, the kinetically derived maximum dose (KMD), has been proposed as a mechanism to integrate toxicokinetic (TK) data into the dose selection process. The approach refers to the dose above which the systemic exposures depart from being proportional to external doses. This non-linear external-internal dose relationship arises from saturation or limitation of TK process(es), such as absorption or metabolism. The importance of TK information is widely acknowledged when assessing human health risks arising from exposures to environmental chemicals, as TK determines the amount of chemical at potential sites of toxicological responses. However, there have been differing opinions and interpretations within the scientific and regulatory communities related to the validity and application of the KMD concept. A multi-stakeholder working group, led by the Health and Environmental Sciences Institute (HESI), was formed to provide an opportunity for impacted stakeholders to address commonly raised scientific and technical issues related to this topic and, more specifically, a weight of evidence approach is recommended to inform design and dose selection for repeated dose animal studies. Commonly raised challenges related to the use of TK data for dose selection are discussed, recommendations are provided, and illustrative case examples are provided to address these challenges or refute misconceptions.

EC50 images, a novel endpoint from PET target occupancy studies, reveal spatial variation in apparent drug affinity

PURPOSE

We recently introduced voxel-level images of drug occupancy from PET via our "Lassen plot filter." Occupancy images revealed clear dependence of ¹¹C-flumazenil displacement on dose of GABAa inhibitor, CVL-865, but with different scales in different brain regions. We hypothesized that regions requiring higher drug concentrations to achieve desired occupancy would have higher EC₅₀ values. We introduce an "EC₅₀ image" from human data to evaluate this hypothesis.

METHODS

Five healthy subjects were scanned with the nonselective GABAa tracer, ¹¹C-flumazenil, before and (twice) after administration of CVL-865. We created ten occupancy images and applied an E_max model locally to create one EC₅₀ image. We also performed simulations to confirm our observations of regional variation in EC₅₀ and to identify the main source of variability in EC₅₀.

RESULTS

As expected, the EC₅₀ image revealed spatial variation in apparent drug affinity. High EC₅₀ was found in areas of low occupancy for a given drug dose. Simulations demonstrated that sampling from an inadequate range of plasma drug concentrations could impair precision.

CONCLUSION

Our results argue for (a) confidence in the ability of the EC₅₀ images to identify regional differences and (b) a need to tailor the range of drug doses in an occupancy study to regularize the precision of the EC₅₀ throughout the brain. The EC₅₀ image could add value to early-phase drug development by identifying regional variation in affinity that might impact therapy or safety and by guiding dose selection for later-phase trials.

A Review of the Dose Justification of Phase 3 Trials to Regulatory Authorities for Drugs Intended for the Treatment of Type 2 Diabetes in Europe

Aims: Cardiovascular outcome trials with anti-diabetic drugs suggest that additional cardiovascular benefit can be achieved independent of improving glycaemic control. Nonetheless, dose selection of anti-diabetic drugs is typically based solely on glycaemic effects. We evaluated whether off-target drug effects are currently considered for dose justification to regulatory agencies.

Methods: In the European Union, anti-diabetic drugs are registered by the European Medicines Agency. We extracted available information regarding dose selection from public assessment reports and marketing application dossiers. Descriptive statistics were used to summarise the extracted information.

Results: In total, 14 drugs of three drug classes were included; sodium-glucose co-transporter-2 inhibitors (n = 4), dipeptidyl peptidase-4 inhibitors (n = 4) and glucagon-like peptide-1 receptor agonists (n = 6). For these drugs, 21 dose-finding trials were submitted including results of multiple off-target effects, of which body weight (n = 18) and low-density lipoprotein cholesterol (n = 14) were most frequently reported. Dose-response curves for off-target effects appeared to be different compared to the glycaemic dose-response curve. Glycated hemoglobin (100%) and fasting plasma glucose (42.9%), were used most frequently for the dose justification, but generally off-target effects (<25%) were not.

Conclusions: Dose justification to regulatory authorities was mainly based on glycaemic effects. The dose-response relationship for the off-target effects did not necessarily follow the dose-response relationship of the on-target effects suggesting that selection of the optimal anti-diabetic dose could benefit from including off-target effects in the dose selection process as well.

Utility-Based Dose Selection for Phase II Dose-Finding Studies

BACKGROUND AND OBJECTIVES

Dose selection is a key feature of clinical development. Poor dose selection has been recognized as a major driver of development failure in late phase. It usually involves both efficacy and safety criteria. The objective of this paper is to develop and implement a novel fully Bayesian statistical framework to optimize the dose selection process by maximizing the expected utility in phase III.

METHODS

The success probability is characterized by means of a utility function with two components, one for efficacy and one for safety. Each component refers to a dose-response model. Moreover, a sequential design (with futility and efficacy rules at the interim analysis) is compared to a fixed design in order to allow one to hasten the decision to perform the late phase study. Operating characteristics of this approach are extensively assessed by simulations under a wide range of dose-response scenarios.

RESULTS AND CONCLUSIONS

Simulation results illustrate the difficulty of simultaneously estimating two complex dose-response models with enough accuracy to properly rank doses using an utility function combining the two. The probability of making the good decision increases with the sample size. For some scenarios, the sequential design has good properties: with a quite large probability of study termination at interim analysis, it enables to reduce the sample size while maintaining the properties of the fixed design.

Population pharmacokinetic analysis of phase 1 bemarituzumab data to support phase 2 gastroesophageal adenocarcinoma FIGHT trial

Purpose

To report population pharmacokinetic (PK) analysis of the phase 1 study (FPA144-001, NCT02318329) and to select a clinical dose and schedule that will achieve an empirical target trough concentration (C_trough) for an anti-fibroblast growth factor receptor 2b antibody, bemarituzumab.

Methods

Nonlinear mixed-effect modeling was used to analyse PK data. In vitro binding affinity and receptor occupancy of bemarituzumab were determined. Simulation was conducted to estimate dose and schedule to achieve an empirical target C_trough in a phase 2 trial (FIGHT, NCT03694522) for patients receiving first-line treatment combined with modified 5-fluourouracil, oxaliplatin and leucovorin (mFOLFOX6) for gastric and gastroesophageal junction adenocarcinoma.

Results

Bemarituzumab PK is best described by a two-compartment model with parallel linear and nonlinear (Michaelis–Menten) elimination from the central compartment. Albumin, gender, and body weight were identified as the covariates on the linear clearance and/or volume of distribution in the central compartment, and no dose adjustment was warranted. An empirical target of bemarituzumab C_trough of ≥ 60 µg/mL was projected to achieve > 95% receptor occupancy based on in vitro data. Fifteen mg/kg every 2 weeks, with a single dose of 7.5 mg/kg on Cycle 1 Day 8, was projected to achieve the target C_trough on Day 15 in 98% of patients with 96% maintaining the target at steady state, which was confirmed in the FIGHT trial.

Conclusion

A projected dose and schedule to achieve the target C_trough was validated in phase 1 of the FIGHT trial which supported selection of the phase 2 dose and schedule for bemarituzumab.

Electronic supplementary material

The online version of this article (10.1007/s00280-020-04139-4) contains supplementary material, which is available to authorized users.

Intrapulmonary concentrations of meropenem administered by continuous infusion in critically ill patients with nosocomial pneumonia: a randomized pharmacokinetic trial

Background

Optimal antimicrobial drug exposure in the lung is required for successful treatment outcomes for nosocomial pneumonia. Little is known about the intrapulmonary pharmacokinetics (PK) of meropenem when administered by continuous infusion (CI). The aim of this study was to evaluate the PK of two dosages of meropenem (3 g vs 6 g/day by CI) in the plasma and epithelial lining fluid (ELF) in critically ill patients with nosocomial pneumonia.

Methods

Thirty-one patients (81% male, median (IQR) age 72 (22) years) were enrolled in a prospective, randomized, clinical trial. Sixteen patients received 1 g/8 h and 15 2 g/8 h by CI (8 h infusion). Plasma and ELF meropenem concentrations were modeled using a population methodology, and Monte Carlo simulations were performed to estimate the probability of attaining (PTA) a free ELF concentration of 50% of time above MIC (50% fT>MIC), which results in logarithmic killing and the suppression of resistance in experimental models of pneumonia.

Results

The median (IQR) of meropenem AUC_0–24 h in the plasma and ELF was 287.6 (190.2) and 84.1 (78.8) mg h/L in the 1 g/8 h group vs 448.1 (231.8) and 163.0 (201.8) mg h/L in the 2 g/8 h group, respectively. The penetration ratio was approximately 30% and was comparable between the dosage groups. In the Monte Carlo simulations, only the highest approved dose of meropenem of 2 g/8 h by CI allowed to achieve an optimal PTA for all isolates with a MIC < 4 mg/L.

Conclusions

An increase in the dose of meropenem administered by CI achieved a higher exposure in the plasma and ELF. The use of the highest licensed dose of 6 g/day may be necessary to achieve an optimal coverage in ELF for all susceptible isolates (MIC ≤ 2 mg/L) in patients with conserved renal function. An alternative therapy should be considered when the presence of microorganisms with a MIC greater than 2 mg/L is suspected.

Trial registration

The trial was registered in the European Union Drug Regulating Authorities Clinical Trials Database (EudraCT-no. 2016-002796-10). Registered on 27 December 2016.

Criteria for dose-finding in two-stage seamless adaptive design

In pharmaceutical/clinical development, two-stage seamless adaptive designs are commonly considered. Such designs include a two-stage phase I/II or phase II/III adaptive trial that combines one phase IIb study for dose-finding or treatment selection and one phase III study for efficacy confirmation into a single study. At the end of stage 1, promising dose(s) will be selected based on pre-specified selection criteria. In practice, since there is little power with limited subjects available at interim, commonly considered selection criteria for critical decision-making include (i) conditional power, (ii) precision analysis, (iii) predictive probability of success, and (iv) probability of being the best dose or treatment. The selected promising dose(s) will then proceed to the next stage for efficacy confirmation. In this article, we introduce, compare, and evaluate these criteria. Simulation studies and a numeric example are given to illustrate those criteria. Besides, we attempt to address some concerns for the two-stage seamless adaptive clinical trial.

A translational pharmacokinetic/pharmacodynamic model to characterize bacterial kill in the presence of imipenem-relebactam

OBJECTIVES

Relebactam is a small molecule β-lactamase inhibitor under clinical investigation for use as a fixed-dose combination with imipenem/cilastatin. Here we present a translational pharmacokinetic/pharmacodynamic mathematical model to support optimal dose selection of relebactam.

METHODS

Data derived from in vitro checkerboard and hollow fiber infection studies of imipenem-resistant strains of Pseudomonas aeruginosa were incorporated into the model. The model integrates the effect of relebactam concentration on imipenem susceptibility in a semi-mechanistic manner using the checkerboard data and characterizes the bacterial time-kill profiles from the hollow fiber infection model data.

RESULTS

Simulations demonstrated that the ratio of the area under the concentration-time curve for free drug to the minimum inhibitory concentration (fAUC/MIC) was the pharmacokinetic driver for relebactam, with a target fAUC/MIC=7.5 associated with 2-log kill. At a clinical dose of 250mg relebactam, greater than 2-log reductions in bacterial load are projected for imipenem-resistant strains with an imipenem/relebactam MIC≤4μg/mL.

CONCLUSIONS

The study confirms that the pharmacokinetic/pharmacodynamic driver for relebactam is fAUC/MIC, that an fAUC/MIC ratio of 7.5 is associated with 2-log kill in vitro, and that a 250mg clinical dose of relebactam achieves this target value when delivered in combination with imipenem/cilastatin.

Rituximab dosing in hematological malignancies: an old question, revisited

Rituximab is the standard of care for most B-cell malignancies. Its rapid clinical development enabled patients to receive this life-prolonging medicine sooner; however, it precluded a thorough assessment of dose selection. Extensive clinical pharmacology data collected from the recent subcutaneous development program enabled re-examination of this old question and support that the approved rituximab dosing regimens in non-Hodgkin's lymphoma and chronic lymphocytic leukemia appear to maximize the clinical benefit in the majority of patients.

Generalized ROC methods for immunogenicity data analysis of vaccine phase I studies in a seropositive population

Immunogenicity data from phase 1 vaccine studies can be difficult to interpret, especially in seropositive populations and when multiple assays are used. We developed 3 statistical methods (Youden index [YI] threshold, receiver-operating characteristic relative to baseline [ROC-B], and ROC of postdose levels [ROC-P]) to characterize complex immunogenicity data by assessing the proportion of a study population that achieved values above thresholds. The YI method calculates a single threshold per assay. Both ROC methods construct ROC curves for individual assays and surfaces for assay combinations to assess degree of separation of postdose values from a reference distribution; the ROC-B method uses overall predose values as the reference distribution and the ROC-P method uses pooled postdose values. All methods are applicable to a seropositive population with overlapping distributions of baseline and postdose measurements and can evaluate results of multiple assays jointly. The ROC-P method is also applicable when postdose levels are fully separated from baseline levels, as is common in a seronegative population. These methods were demonstrated using data from a phase 1a study of respiratory syncytial virus vaccines formulated with and without an adjuvant in a seropositive population of adults aged ≥60 years. All 3 methods provided a comprehensive assessment of vaccine immunogenicity effects with results presented in easily interpretable formats. In the example data, the methods demonstrated antigen dose response trend and contribution of adjuvant to response in multiple assays individually and jointly where optimal responses in assay combinations (humoral and cellular) are important.

Nonclinical Development of Combination Drugs

We define "combination drugs" as "fixed-dose combinations" (FDCs), that is, two or more drugs (marketed or not) combined in a single pill or two or more separate drugs packaged together. FDCs have been available commercially for many years but only relatively recently have nonclinical development guidelines been released by a number of regulatory authorities and the World Health Organization; as yet there are no ICH guidelines specific to combination drugs. In general however, the ICH guidelines for monotherapy development provide a framework for FDC development. Depending on the type of drug combination (marketed drug/marketed drug; marketed drug/NME and NME/NME) the scope and complexity of toxicity studies will vary greatly. In all cases however, a key issue is the potential for pharmacokinetic and/or toxicologic interaction between the components. For a marketed drug/marketed drug combination a detailed review of the nonclinical data available may suffice, particularly when the components have a history of coadministration at about the same dose and ratio as that of the proposed combination. For a marketed drug/NME combination, in addition to a review of the data for the marketed drug, a full ICH program of studies will be required for the NME, and a study of up to 90-day duration (in one species) for the combination. With an NME/NME combination each component will require a full ICH battery of studies and a combination study in one species. In all cases additional studies may be needed to address data gaps. Given the many novel and complex issues which arise when developing FDCs we recommend that, whenever possible, the nonclinical study strategy is discussed with the regulatory authorities.

Drug related problems identified by clinical pharmacist at the Internal Medicine Ward in Turkey

Background Drug-related problems (DRPs) interfere with patient optimal therapeutic outcomes and may be associated with higher morbidity, mortality and healthcare expenditures. Objective This study aimed to identify DRPs and their causes in a Turkish hospital. Setting Bakirkoy Dr. Sadi Konuk Teaching and Research Hospital, Internal Medicine Ward, Istanbul, Turkey. Method Cross-sectional study included a total of 100 patients. Patient demographics, medications, and history were evaluated. Data regarding recent medications were analyzed by two clinical pharmacists and an Internal Medicine physician. The DRPs were identified via V7.0 PCNE classification. Lexicomp^® was used to assess the drug-drug interactions. UpToDate^® recommendations and national guidelines were applied in the assessment of compliance with approved medication procedures. Main outcome measures Number and causes of the potential DRPs. Results At least one potential DRP was seen in 80% of the patients and 163 potential DRPs were identified (average = 1.6 DRPs/patient). The most common causes of DRPs were errors in drug selection (44.78%), dose selection (27.61%) and medication procedures (21.47%). There were significant correlations (p < 0.05) between DRPs and age (r = 0.4), number of drugs used (r = 0.32), duration of hospitalization (r = 0.25), renal impairment (r = - 0.34) and inflammation (r = 0.31). Conclusion The majority of the patients had DRPs. Patients with renal impairment, inflammation, polypharmacy or an extended hospital stay had a much higher chance of developing DRPs.

Advances of radiation sterilisation in tissue banking

Under the auspices of the IAEA tissue banking programme on "Radiation Sterilisation of Tissue Graft" conducted from 1985 to 2004, many scientists and surgeons were involved in various regional research and development (R&D) projects mainly in dealing with radiation dose selection, radiation effects on human tissues and quality system in radiation sterilisation. New findings on radiation effects, tissue processing and preservation were shared during the regional and interregional meetings and workshops. Many tissue banks started to use radiation (25 kGy) to sterilize tissue grafts for tissue safety and efficacy and still continue to use it. The IAEA Code of Practice for Radiation Sterilization of Tissues Allografts developed in 2007 offered simpler methods to conduct radiation dose setting and dose validation experiments for tissue grafts. Advances in dose selection and dose mapping are continued under the quality management system when banks need to be certified to continue their operation. The combination of good tissue processing and preservation as well as good radiation practice will ensure the tissue products are properly sterilised thus safe and of high quality. Experience in meeting challenges in using radiation sterilisation and achievements reported by the tissue bankers are shared here.

Bayesian dose selection design for a binary outcome using restricted response adaptive randomization

Background

In phase II trials, the most efficacious dose is usually not known. Moreover, given limited resources, it is difficult to robustly identify a dose while also testing for a signal of efficacy that would support a phase III trial. Recent designs have sought to be more efficient by exploring multiple doses through the use of adaptive strategies. However, the added flexibility may potentially increase the risk of making incorrect assumptions and reduce the total amount of information available across the dose range as a function of imbalanced sample size.

Methods

To balance these challenges, a novel placebo-controlled design is presented in which a restricted Bayesian response adaptive randomization (RAR) is used to allocate a majority of subjects to the optimal dose of active drug, defined as the dose with the lowest probability of poor outcome. However, the allocation between subjects who receive active drug or placebo is held constant to retain the maximum possible power for a hypothesis test of overall efficacy comparing the optimal dose to placebo. The design properties and optimization of the design are presented in the context of a phase II trial for subarachnoid hemorrhage.

Results

For a fixed total sample size, a trade-off exists between the ability to select the optimal dose and the probability of rejecting the null hypothesis. This relationship is modified by the allocation ratio between active and control subjects, the choice of RAR algorithm, and the number of subjects allocated to an initial fixed allocation period. While a responsive RAR algorithm improves the ability to select the correct dose, there is an increased risk of assigning more subjects to a worse arm as a function of ephemeral trends in the data. A subarachnoid treatment trial is used to illustrate how this design can be customized for specific objectives and available data.

Conclusions

Bayesian adaptive designs are a flexible approach to addressing multiple questions surrounding the optimal dose for treatment efficacy within the context of limited resources. While the design is general enough to apply to many situations, future work is needed to address interim analyses and the incorporation of models for dose response.

Nivolumab dose selection: challenges, opportunities, and lessons learned for cancer immunotherapy

Background

Immuno-oncology (I-O) therapies target the host immune system, providing the potential to choose a uniform dose and schedule across tumor types. However, dose selection for I-O agents usually occurs early in clinical development and is typically based on tumor response, which may not fully represent the potential for improved overall survival. Here, we describe an integrated approach which incorporates clinical safety and efficacy data with data obtained from analyses of dose-/exposure-response (D-R/E-R) relationships, used to select a monotherapy dose for nivolumab, a programmed death–1 inhibitor, in clinical studies of different tumor types.

Methods

Dose was selected based on anti-tumor activity and safety data from a large phase 1b, open-label, dose-escalation study of nivolumab at doses ranging from 0.1 to 10 mg/kg administered every 2 weeks (Q2W) in 306 patients with advanced malignancies, and quantitative analyses were performed to characterize D-R/E-R relationships for pharmacodynamic, safety, and efficacy endpoints.

Results

A maximum tolerated dose for nivolumab was not identified, and the safety profile was similar across tumor types and dose levels (0.1–10 mg/kg). Objective response rates (ORRs) were similar across doses in melanoma and renal cell carcinoma (RCC), while higher ORRs were observed in non-small cell lung cancer (NSCLC) at 3 mg/kg and 10 mg/kg versus 1 mg/kg. Peripheral receptor occupancy was saturated at doses ≥ 0.3 mg/kg. In D-R/E-R analyses, a positive dose-dependent objective response trend was observed for each tumor type, but appeared to plateau at nivolumab doses of ≥ 1 mg/kg for melanoma and RCC, and at ≥ 3 mg/kg for NSCLC. Although there was no apparent relationship between tumor shrinkage rate and exposure, tumor progression rate appeared to decrease with increasing exposure up to a dose of 3 mg/kg Q2W for NSCLC.

Conclusions

Nivolumab monotherapy at 3 mg/kg Q2W provides unified dosing across tumor types. This dose and schedule has been validated in several phase II/III studies in which overall survival was an endpoint. Integrating D-R/E-R relationships with efficacy data and a safety profile that is unique to I-O therapy is a rational approach for dose selection of these agents.

Electronic supplementary material

The online version of this article (doi:10.1186/s40425-016-0177-2) contains supplementary material, which is available to authorized users.

Chemotherapy plus Ofatumumab at Standard or Mega dose in relapsed CLL (COSMIC) trial: study protocol for a phase II randomised controlled trial

Background

Chronic lymphocytic leukaemia (CLL) is the most common adult leukaemia. Combination immunochemotherapy such as fludarabine, cyclophosphamide and rituximab is the standard first line therapy in fit patients, but there is limited evidence regarding the optimal treatment of patients after relapse. Ofatumumab as monotherapy has been proven to be effective in the treatment of relapsed, refractory CLL, and as it is not myelotoxic, it is an ideal drug to combine with chemotherapy. However, the optimal dose of ofatumumab in this setting is not known. The Chemotherapy plus Ofatumumab at Standard or Mega dose in relapsed CLL (COSMIC) trial will assess the efficacy and safety of standard and high (mega) doses of ofatumumab combined with bendamustine or a combination of fludarabine and cyclophosphamide to determine which, if either, schedule should progress to a phase III trial.

Methods/design

COSMIC is a phase II, multi-centre, randomised, open, parallel group trial for patients with relapsed CLL who are not refractory to fludarabine-based chemotherapy. Participants will be randomised to receive either standard dose or mega dose ofatumumab. Both doses will be given in combination with either bendamustine or fludarabine and cyclophosphamide chemotherapy backbone. The primary objective is to assess the proportion of participants achieving a complete remission following therapy with the two treatment arms (mega versus standard), as assessed at 3 months post treatment. The treatment groups will be assessed independently to determine whether the level of response is acceptable in relation to pre-specified criteria. If both treatment groups show an acceptable level of response, selection criteria will be used to determine which to take forward to a confirmatory phase III trial. A key secondary objective is to assess the dynamics of minimal residual disease (MRD) levels in relapsed disease. Eighty-two participants are planned to be recruited from 18 research centres in the UK.

Discussion

Currently there is limited evidence regarding the optimal treatment of patients with relapsed or refractory CLL, and so suitable therapies are urgently needed. The COSMIC trial will identify whether ofatumumab given in combination with chemotherapy is safe and effective in this population, and will identify the optimal doses for further investigation.

Trial registration

ISRCTN51382468. Registered on 21 September 2011.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1581-0) contains supplementary material, which is available to authorized users.

A survey of new oncology drug approvals in the USA from 2010 to 2015: a focus on optimal dose and related postmarketing activities

The maximally tolerated dose (MTD) of cytotoxic agents has historical precedence in treating cancer, as it was believed that dose and therapeutic effect are intrinsically linked and that the MTD would provide greatest therapeutic value. With molecularly targeted agents, the premise of preventing toxicity to normal tissues while modulating tumor growth provides a potential for an increased therapeutic window. Results from these targeted agents suggest we are entering an era of chronic cancer management, which will require design of regimens with long-term tolerability. A corresponding switch from MTD-based (toxicity-driven) dosing strategies to alternative paradigms is also expected. The challenge with these targeted agents is to fully understand the complex relationship between pharmacokinetics, pharmacodynamics, and safety and efficacy in early-stage trials, so that the optimal dose and schedule for registration trials may be identified. This review provides a systematic survey of the applications submitted to the United States Food and Drug Administration (FDA) for oncology indications, from 2010 through early 2015, and summarizes the dose selection rationale for registrational trials, the relationship of the MTD to outcomes of the final label dose, the postmarketing requirements or commitments related to dose optimization activities, the role of biomarkers, and typical exposure-response modeling methods.

An Adaptive Staggered Dose Design for a Normal Endpoint

In a clinical trial where several doses are compared to a control, a multi-stage design that combines both the selection of the best dose and the confirmation of this selected dose is desirable. An example is the two-stage drop-the-losers or pick-the-winner design, where inferior doses are dropped after interim analysis. Selection of target dose(s) can be based on ranking of observed effects, hypothesis testing with adjustment for multiplicity, or other criteria at interim stages. A number of methods have been proposed and have made significant gains in trial efficiency. However, many of these designs started off with all doses with equal allocation and did not consider prioritizing the doses using existing dose-response information. We propose an adaptive staggered dose procedure that allows explicit prioritization of doses and applies error spending scheme that favors doses with assumed better responses. This design starts off with only a subset of the doses and adaptively adds new doses depending on interim results. Using simulation, we have shown that this design performs better in terms of increased statistical power than the drop-the-losers design given strong prior information of dose response.