Assessment of benefits and risks in development of targeted therapies for cancer--The view of regulatory authorities

Strength of statistical evidence for the efficacy of cancer drugs: a Bayesian reanalysis of randomized trials supporting Food and Drug Administration approval

OBJECTIVES

To quantify the strength of statistical evidence of randomized controlled trials (RCTs) for novel cancer drugs approved by the Food and Drug Administration in the last 2 decades.

STUDY DESIGN AND SETTING

We used data on overall survival (OS), progression-free survival, and tumor response for novel cancer drugs approved for the first time by the Food and Drug Administration between January 2000 and December 2020. We assessed strength of statistical evidence by calculating Bayes factors (BFs) for all available endpoints, and we pooled evidence using Bayesian fixed-effect meta-analysis for indications approved based on 2 RCTs. Strength of statistical evidence was compared among endpoints, approval pathways, lines of treatment, and types of cancer.

RESULTS

We analysed the available data from 82 RCTs corresponding to 68 indications supported by a single RCT and 7 indications supported by 2 RCTs. Median strength of statistical evidence was ambiguous for OS (BF = 1.9; interquartile range [IQR] 0.5-14.5), and strong for progression-free survival (BF = 24,767.8; IQR 109.0-7.3 × 106) and tumor response (BF = 113.9; IQR 3.0-547,100). Overall, 44 indications (58.7%) were approved without clear statistical evidence for OS improvements and 7 indications (9.3%) were approved without statistical evidence for improvements on any endpoint. Strength of statistical evidence was lower for accelerated approval compared to nonaccelerated approval across all 3 endpoints. No meaningful differences were observed for line of treatment and cancer type. This analysis is limited to statistical evidence. We did not consider nonstatistical factors (eg, risk of bias, quality of the evidence).

CONCLUSION

BFs offer novel insights into the strength of statistical evidence underlying cancer drug approvals. Most novel cancer drugs lack strong statistical evidence that they improve OS, and a few lack statistical evidence for efficacy altogether. These cases require a transparent and clear explanation. When evidence is ambiguous, additional postmarketing trials could reduce uncertainty.

Evidence synthesis analysis with prioritized benefit outcomes in oncology clinical trials

Overall survival, progression-free survival, objective response/complete response, and duration of (complete) response are frequently used as the primary and secondary efficacy endpoints for designs and analyses of oncology clinical trials. However, these endpoints are typically analyzed separately. In this article, we introduce an evidence synthesis approach to prioritize the benefit outcomes by applying the generalized pairwise comparisons (GPC) method, and use win statistics (win ratio, win odds and net benefit) to quantify treatment benefit. Under the framework of GPC, the main advantage of this evidence synthesis approach is the ability to combine relevant outcomes of various types into a single summary statistic without relying on any parametric assumptions. It is particularly relevant since health authorities and the pharmaceutical industry are increasingly incorporating structured quantitative methodologies in their benefit-risk assessment. We apply this evidence synthesis approach to an oncology phase 3 study in first-line renal cell carcinoma to assess the overall effect of an investigational treatment by ranking the most clinically relevant endpoints in cancer drug development. This application and a simulation study demonstrate that the proposed approach can synthesize the evidence of treatment effect from multiple prioritized benefit outcomes, and has substantial advantage over conventional methods that analyze each individual endpoint separately. We also introduce a newly developed R package WINS for statistical inference based on win statistics.

Global Landscape of Benefit-Risk Considerations for Medicinal Products: Current State and Future Directions

In the last decade there has been a significant increase in the literature discussing the use of benefit-risk methods in medical product (including devices) development. Government agencies, medical product industry groups, academia, and collaborative consortia have extensively discussed the advantages of structured benefit-risk assessments. However, the abundance of information has not resulted in a consistent way to utilize these findings in medical product development. Guidelines and papers on methods, even though well structured, have not led to a firm consensus on a clear and consistent approach. This paper summarizes the global landscape of benefit-risk considerations for product- or program-level decisions from available literature and regulatory guidance, providing the perspectives of three stakeholder groups-regulators, collaborative groups and consortia, and patients. The paper identifies key themes, potential impact on benefit-risk assessments, and significant future trends.

Characteristics of Single Pivotal Trials Supporting Regulatory Approvals of Novel Non-orphan, Non-oncology Drugs in the European Union and United States from 2012-2016

For regulatory approval of a new medicine, the gold standard for demonstration of efficacy has traditionally been a minimum of two positive, adequate, and well‐controlled clinical trials. Nevertheless, drugs to treat cancer and rare diseases are usually approved based on a single and often uncontrolled pivotal trial. In contrast, little is known about single pivotal trial approvals for non‐orphan, non‐oncology drugs. Between 2012 and 2016, 23 novel therapeutic drugs were approved by the US Food and Drug Administration (FDA) and/or the European Medicines Agency (EMA) for 27 non‐orphan, non‐oncology indications each based on a single pivotal trial. Although there was considerable variation in the nature and strength of the efficacy evidence supporting these drug approvals, the majority (85%) of the pivotal trials were randomized and controlled. For all superiority trials, the primary outcome was met with a statistical significance of P ≤ 0.005. Most approvals were supported by additional efficacy data from nonpivotal studies.

Evaluation of Riboflavin Transporters as Targets for Drug Delivery and Theranostics

The retention and cellular internalization of drug delivery systems and theranostics for cancer therapy can be improved by targeting molecules. Since an increased uptake of riboflavin was reported for various cancers, riboflavin and its derivatives may be promising binding moieties to trigger internalization via the riboflavin transporters (RFVT) 1, 2, and 3. Riboflavin is a vitamin with pivotal role in energy metabolism and indispensable for cellular growth. In previous preclinical studies on mice, we showed the target-specific accumulation of riboflavin-functionalized nanocarriers in cancer cells. Although the uptake mechanism of riboflavin has been studied for over a decade, little is known about the riboflavin transporters and their expression on cancer cells, tumor stroma, and healthy tissues. Furthermore, evidence is lacking concerning the representativeness of the preclinical findings to the situation in humans. In this study, we investigated the expression pattern of riboflavin transporters in human squamous cell carcinoma (SCC), melanoma and luminal A breast cancer samples, as well as in healthy skin, breast, aorta, and kidney tissues. Low constitutive expression levels of RFVT1-3 were found on all healthy tissues, while RFVT2 and 3 were significantly overexpressed in melanoma, RFVT1 and 3 in luminal A breast cancer and RFVT1-3 in SCC. Correspondingly, the SCC cell line A431 was highly positive for all RFVTs, thus qualifying as suitable in vitro model. In contrast, activated endothelial cells (HUVEC) only presented with a strong expression of RFVT2, and HK2 kidney cells only with a low constitutive expression of RFVT1-3. Functional in vitro studies on A431 and HK2 cells using confocal microscopy showed that riboflavin uptake is mostly ATP dependent and primarily driven by endocytosis. Furthermore, riboflavin is partially trafficked to the mitochondria. Riboflavin uptake and trafficking was significantly higher in A431 than in healthy kidney cells. Thus, this manuscript supports the hypothesis that addressing the riboflavin internalization pathway may be highly valuable for tumor targeted drug delivery.

Perspectives on the integration of Immuno-Oncology Biomarkers and drugs in a Health Care setting

Immunotherapies, specifically checkpoint inhibitors, are becoming an important component in cancer care with the most application now in melanoma and lung cancer patients. Some drawbacks that converge with this new evolution are the rather low response rates to these drugs and their high cost with a significant economic impact on the health care system. These major challenges can likely be circumvented by implementing a "personalized immuno-oncology" approach to accomplish a selection of optimal responders based on biomarkers. In this paper we first discuss the legal framework for the development of valuable in vitro diagnostics. Based on a case study in lung cancer, the clinical validity and utility requirements of predictive immuno-oncology biomarkers is highlighted and an overview is given on the evolution towards multiplex or omics-based assays together with its challenges and pitfalls. Finally, some initiatives between the public and private sector are pinpointed to sustain the future access to innovative medicines in cancer therapy at a reasonable cost.

Spanish Cultural Adaptation of the Questionnaire Early Arthritis for Psoriatic Patients

INTRODUCTION AND OBJECTIVES

The Early Arthritis for Psoriatic patients (EARP) questionnaire is a screening tool for psoriatic arthritis. The original Italian version has good measurement properties but the EARP required translation and adaptation for use in Spain. This article describes the cultural adaptation process as a step prior to validation.

MATERIAL AND METHODS

We used the principles of good practice for the cross-cultural adaptation of patient-reported outcomes measurement established by the International Society Pharmacoeconomics and Outcome Research. The steps in this process were preparation, forward translation, reconciliation, back-translation and review, harmonization, cognitive debriefing and review, and proofreading. During preparation the developers of the original questionnaire were asked for their permission to adapt the EARP for use in Spain and to act as consultants during the process.

RESULTS

The original questionnaire was translated into Spanish by native Spanish translators, who made slight changes that were approved by the questionnaire's developers. The Spanish version was then back-translated into Italian; that version was reviewed to confirm equivalence with the original Italian text. The reconciled Spanish EARP was then tested for comprehensibility and interpretation in a group of 35 patients. All the patients answered all items without making additional comments.

CONCLUSION

This cultural adaptation of the EARP questionnaire for Spanish populations is the first step towards its later use in routine clinical practice. The application of a cross-cultural adaptation method ensured equivalence between the original and Spanish versions of the EARP. The Spanish questionnaire will be validated in a second stage.

Comparative Safety of Vaccine Adjuvants: A Summary of Current Evidence and Future Needs

Use of highly pure antigens to improve vaccine safety has led to reduced vaccine immunogenicity and efficacy. This has led to the need to use adjuvants to improve vaccine immunogenicity. The ideal adjuvant should maximize vaccine immunogenicity without compromising tolerability or safety. Unfortunately, adjuvant research has lagged behind other vaccine areas such as antigen discovery, with the consequence that only a very limited number of adjuvants based on aluminium salts, monophosphoryl lipid A and oil emulsions are currently approved for human use. Recent strategic initiatives to support adjuvant development by the National Institutes of Health should translate into greater adjuvant choices in the future. Mechanistic studies have been valuable for better understanding of adjuvant action, but mechanisms of adjuvant toxicity are less well understood. The inflammatory or danger-signal model of adjuvant action implies that increased vaccine reactogenicity is the inevitable price for improved immunogenicity. Hence, adjuvant reactogenicity may be avoidable only if it is possible to separate inflammation from adjuvant action. The biggest remaining challenge in the adjuvant field is to decipher the potential relationship between adjuvants and rare vaccine adverse reactions, such as narcolepsy, macrophagic myofasciitis or Alzheimer's disease. While existing adjuvants based on aluminium salts have a strong safety record, there are ongoing needs for new adjuvants and more intensive research into adjuvants and their effects.

Assessment of benefits and risks in development of targeted therapies for cancer--The view of regulatory authorities

Drug licensing and approval decisions involve the balancing of benefits against the risks (harms) in the presence of uncertainty. Typically, the benefits are estimated from primary efficacy endpoints from confirmatory (phase III) clinical trials although exceptions where promising early data from single-arm studies have led to accelerated approvals are not uncommon, particularly for cancer drugs. The challenge for regulators is to balance early evidence of efficacy that might support approval versus the need to establish clinical benefit based on conclusive evidence. Targeted agents offer the promise that knowledge about the mechanism of the disease will help identify patients with tumors likely to respond, resulting in higher efficacy and less toxicity, and earlier regulatory decisions based on convincing evidence of clinical benefit. In this paper, we describe methods and examples of benefit-risk assessment of targeted drugs, recent initiatives from EMA and FDA on improving communication about benefits and risks, and discuss future steps.