As cancer patients are surviving longer, there is growing interest in better understanding the potential for cardiovascular complications associated with cancer therapies. Indeed, over four decades, clinical data have shown that oncology treatments-from chemotherapies to targeted immunotherapies-can negatively impact heart health. Risks include ischemia, vascular disease, cardiomyopathy, myocarditis, hypertension, heart failure, arrhythmias, QT prolongation, and thrombosis.

^1,2,3

Often, patients face a tradeoff of the benefits and risks of treatment. Herceptin, for example, revolutionized the treatment of breast cancer, but also produced congestive heart failure in many patients.

Thus, the FDA requires cardiac safety monitoring in oncology trials. And experienced clinical development teams understand and apply the evolving body of clinical research and therapeutic-level recommendations to clinical trial protocols in order to monitor for these cardiac conditions. Yet, the imaging required to monitor for cardiotoxicities during clinical development can, at times, be treated as a perfunctory task.

The fact is, for cardiac safety trials, as in all clinical studies involving imaging, it matters how images are taken, how they are analyzed, and how the process is monitored. The quality and capabilities of the imaging management system-the process and tools used to collect, share, interpret, and store images-has an appreciable impact on patient safety as well as trial costs and timelines.

Cardiac imaging in oncology trials

Imaging is commonly used as a biomarker for safety in oncology development and, in many trials, is the primary efficacy endpoint. Echocardiography is used to assess symptomatic and asymptomatic cardiac dysfunction in oncology patients and to grade the severity of the condition; the results are surrogate markers for cardiac safety.

The availability of high-resolution and sensitive imaging techniques allows for the identification of potential pathological changes earlier (e.g., decline in left ventricular ejection fraction (LVEF), acute myocarditis, and valve leaflet thickening).

Such assessments are performed in order to:

• Make go/no-go decisions for continued drug development

• Understand baseline risk

• Assist in identifying high-risk subgroups within the population (for example, subjects with low ejection fraction or ventricular volume)

• Screen subjects for protocol eligibility

• Monitor patients for treatment-emergent changes, which may necessitate the need for dose adjustment or treatment discontinuation

The study team will recommend the monitoring frequency based on an understanding of the drug’s mechanism of action, the intended patient population(s), the drug toxicity profile, and a review of prior clinical and non-clinical data.

Early detection and diagnosis of cardiotoxicity is, of course, important, as the goal is to be able to medically intervene, prevent delayed effects, and improve outcomes for the patients. And, should the investigational product need to be re-engineered in the lab, it is better to determine this as early as possible in the development path.

Increasingly, echocardiography is the primary assessment tool for cardiac safety assessments, given its advantages of wide availability, lower cost, and the improved detection three-dimensional methods afford.

A critical factor in patient care and data integrity

Several factors can impact the quality of data produced through echocardiography, as with other imaging modalities.

First, the sonographer’s skill, experience, and knowledge can influence the quality of the image. Second, there can be variations in how the image is acquired, such as the display or resolution, which are related to the equipment itself. And, third, how individual readers interpret the images can-and does-vary. Studies conducted since 1947 have measured diagnostic discordance in the 25% to 40% range.^4,5

Indeed, wide variability in both quantitative and qualitative echocardiography assessments is recognized in recent guidance publications offered by both the European Society of Cardiology (ESC) and the American Society of Echocardiography (ASE).

Errors and inconsistencies can have a direct impact on patient care, as well as on the chance of regulatory approval for the investigational product. Thus, there’s a need for a comprehensive approach to ensuring that image acquisition techniques are standardized, that images are appropriately collected to the highest quality standard across multiple sites, and that the images are evaluated consistently to support the study protocol endpoints. That’s why imaging management systems and active reader management practices are critical. Additionally, the recent ASE Echocardiography Report recommends the use of a centralized echo-reading laboratory in multicenter clinical trials.⁶

Imaging management technology: Added transparency, reduced risk

Today’s imaging technology platforms can help reduce the chance of human error, speed the assessment process, increase objectivity and consistency, and improve patient safety. A single system is used to collect the source data (which is input directly by the clinical trial site staff), manage image analysis, report on the results, and archive records. Because the data are always contained in the same system, there are no delays or errors caused by transferring it between different platforms to perform various operational tasks. This, in fact, eliminates virtually 100% of transcription errors. Furthermore, a consistent process is applied using standardized procedures in a common viewing platform.

The best systems available provide:

• Real-time safety monitoring. Imaging results are collected at the clinical site and are immediately available at the clinical institution, so safety signals can be identified at once for clinical decision-making. They are also immediately available to independent or blinded readers (BICR) so that they can make their independent assessments. The results can also be shared with other stakeholders such as sponsors, cardiac advisory boards, and data and safety monitoring committees.

• Visibility to all study data in near real time. Trial managers and medical directors have total visibility to all study imaging data, throughout the imaging life cycle. They can:

• View reader assessments

• Monitor intra/inter reader variability

• Measure the degree of discordance between site-based and blinded, central readers

• Track the number of cases requiring adjudication

• Monitor for selection bias in adjudicated cases

Such insight into reader workloads and performance makes it possible to quickly address issues around reader drift, variability, and bias, thus minimizing their impact. If, for example, it becomes clear from the metrics that a reader’s approach has changed, retraining can be provided so that the reader’s performance is consistent with others in the reader pool.

• Automated workflows. The system delivers reminders and gives users automatic prompts so that images pass through the agreed-upon workflow from reader to reader to adjudicator as efficiently as possible. The process is not dependent upon a project manager to keep it on track.

• Software-guided and AI-assisted reads. Image analysis software can direct a reader through the analysis of each imaging time point and even pre-process and segment anatomical structures of interest in lockstep with the study’s imaging charter and image evaluation protocol (IEP). This minimizes protocol deviations and ensures that each reader’s unique bias does not creep into the analysis process by focusing the reader on targeted endpoints whose workflows are outline in the trial-specific IEP. Artificial intelligence (AI) can be used to augment human assessment. Using AI in this way can reduce read times by as much as 50% and the need for adjudication by 20%. It would, in the process, increase speed and reduce costs.

Active reader management: Added efficiency and effectiveness

An imaging core lab will be concerned with all of the controllable factors that impact data quality, from data collection to image review and data analysis. The best practices of an imaging core lab include:

• Ensuring that the imaging endpoints support the protocol

• Selecting a limited number of independent readers based on their training and experience

• Managing the image assessment-starting with training on the system and standardizing the imaging protocol and reading criteria

• Monitoring reader performance periodically during the study to lower variability and adjudication rates (readers are asked to re-read cases to identify performance drift)

• Reporting on imaging status and reader performance with recommendations for discussion and intervention if needed

The lab’s ability to monitor reader performance and oversee imaging progress is dependent upon the capabilities of the imaging management software.

Achieving success: Tips for sponsors

Ensuring the validity of cardiac imaging data points in oncology clinical trials is difficult, and the challenge must be addressed early in study planning to both protect patients and the integrity of the trial itself. Sponsors should:

• Look to both positive and negative results in early trials to determine the potential predictive value of cardiac endpoints.

• Identify patients at risk for cardiotoxicity and determine how to balance survival benefits with reduced cardiac risk relative to a patient’s quality of life. (There is a higher tolerance for adverse events in oncologic treatments, and the benefit/risk balancing point is different than in other disease states.)

• Clearly define the protocol-required cardiac assessments and measurement parameters to be obtained during the echocardiogram. This will help the clinical team understand patients’ clinical course and inform decisions on treatment adjustments that may be needed to maintain or restore normal cardiac function. The protocol should include details on the number of imaging findings required, together with information based on statistical analysis to assist investigators in managing patients.

• Establish a baseline of cardiac performance prior to treatment, perform serial assessments during the trial, and conduct a follow-up assessment post-therapy. 

• Pay particular attention to the technologies and processes used to ensure accuracy in how images are taken and interpreted.

Questions to ask your imaging partner in cardiac safety trials

• Which system is used to collect imaging endpoints?

• How quickly are the data available? How easy is the analysis?

• How precise are the assessments?

• What is the expected rate of reader discordance?

• What is the optimal number of independent readers for the trial?

• What has the adjudication rate been on similar trials?

• What process is used to monitor the timeliness and accuracy of reads?

• What process/technology is in place for creating an audit trail and ensuring compliance?

• What systems and training are in place to ensure that sites know how to follow the imaging protocol?

Conclusion

Ensuring that imaging in cardiac safety clinical trials is managed expertly and with the benefit of the latest technology and careful oversight has broad implications for patient safety as well as trial cost and timing. Overall error rates can be reduced by as much as 20%, read times can be reduced by up to 50%, and adjudication rates can be cut
by 20%.

References

1. Blaes, AH, Thavendiranathan, P, Moslehi J. Cardiac Toxicities in the Era of Precision Medicine: Underlying Risk Factors, Targeted Therapies, and Cardiac Biomarkers; 2018 ASCO Educational Book (Print ISSN: 1548-8748 38; Electronic ISSN: 1548-8756) published by the American Society of Clinical Oncology, Inc. (“ASCO”), volume 38, p764-774
2. Zamorano JL, Lancellotti P, Rodriguez Muñoz D, Aboyans V, Asteggiano R, Galderisi M, et al. 2016 ESC Position Paper on cancer treatments and cardiovascular toxicity developed under the auspices of the ESC Committee for Practice Guidelines: The Task Force for cancer treatments and cardiovascular toxicity of the European Society of Cardiology (ESC) Eur Heart J. 2016 Sep 21;37(36):2768-2801
3. Curigliano, G, Mayer EL, Burstein, HJ, Winer EP, Goldhirsch A. Cardiac Toxicity From Systemic Cancer Therapy: A Comprehensive Review; Progress in Cardiovascular Diseases 53 (2010) 94–104
4. Birkelo, C.C., et al., “Tuberculosis case finding: A Comparison of the effectiveness of various roentgenographic and photofluorographic methods. Journal of the American Medical Association, 1947. 133(6): p. 359-366
5. Pinto, A., et al., “The concept of error and malpractice in radiology,” Seminars in Ultrasound, CT, and MRI, 2012, Elsevier
6. American Society of Echocardiography Recommendations for Use of Echocardiography in Clinical Trials A Report from the American Society of Echocardiography’s Guidelines and Standards Committee and The Task Force on Echocardiography in Clinical Trials, Writing Committee: John S. Gottdiener, MD (Chair), James Bednarz, BS, RDCS, Richard Devereux, MD, Julius Gardin, MD, Allan Klein, MD, Warren J. Manning, MD, Annitta Morehead, BA, RDCS, Dalane Kitzman, MD, Jae Oh, MD, Miguel Quinones, MD, Nelson B. Schiller, MD, James H. Stein, MD, and Neil J. Weissman, MD; J Am Soc Echocardiogr 2004;17:1086-1119

Joseph Pierro, MD, Medical Director, Imaging, ERT; Robert Kleiman, MD, Vice President and Chief Medical Officer, Cardiology, ERT