A University of Houston College of Pharmacy Ph.D. graduate has earned one of three UH 2023 Outstanding Dissertation Awards for his research highlighting the benefits of implementing guideline-recommended treatment with a newer class of anticancer drugs, especially among a patient population generally not well represented in clinical trials: older adults on Medicare.
The dissertation by Ravi K. Goyal, Ph.D. (’22), "Impact of Cyclin-Dependent Kinase 4 and 6 Inhibitors on Chemotherapy Utilization and Overall Survival in Women with HR+/HER2– Metastatic Breast Cancer in the United States," was selected as the top presentation in the Biological Sciences/Life Sciences category. His project will be submitted for nomination in the national Council of Graduate Schools/ProQuest national Distinguished Dissertation Award competition.
Following his graduation in 2022, Goyal joined RTI Health Solutions, a business unit of global nonprofit research organization RTI International headquartered in Research Triangle Park, N.C. He serves as senior director, health economics, at RTI.
Uncertainty in early utilization of new chemotherapy
Metastatic breast cancer (MBC) in women remains one of the most challenging forms of cancer to treat for clinicians and researchers, with the five-year survival rate increasing only a modest 6% percentage point from 23% in 1999 to 29% in 2017. Goyal notes that for MBC patients with the hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2–) molecular subtype, clinical practice guidelines advocate for three sequential lines of endocrine (hormone) therapy.
Yet, several observational studies highlighted that chemotherapy continued to see substantially high utilization in the early lines of treatment. In 2015, an entirely new class of drugs called cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors saw their first FDA approval following improved clinical outcomes in HR+/HER2– MBC. Although now considered the preferred choice for the first-line therapy to inhibit the activity of proteins contributing to cancer cell growth, Goyal noted that evidence related to their success in reducing early chemotherapy utilization was unknown and their effect on overall survival rate remained mixed.
Goyal’s research illustrates that chemotherapy utilization in earlier therapy lines for HR+/HER2– MBC declined steadily between 2010 and 2019. These declines were significantly accelerated by the introduction of CDK4/6 therapy class in 2015, notably in the second- and third-line settings.
Improved survival among older Medicare patients
Further, his research makes notable contribution to MBC literature by showing that the “addition of CDK4/6 inhibitors to ET significantly improved overall survival among older Medicare beneficiaries with HR+/HER2– MBC who are generally not well represented in clinical trials, further highlighting the importance of assessing these outcomes from the perspective of Medicare, which provides healthcare coverage to more than 55 million individuals aged 65 years and older in the U.S.”
In his research, Goyal also identified several factors, including social determinants of health, that influence whether Medicare patients receive the next-generation CDK4/6 therapy. Goyal stated in his dissertation, “These results offer an insight into potential disparities in access to these novel therapies and will help foster equity in the delivery of breast cancer care. Medicare policymakers should explore strategies to minimize disparities in access to these expensive but effective treatments, especially for patients living in the areas with low median household income.”
Two papers based on his dissertation work were published in the peer-reviewed journals Breast Cancer Research and Treatment and Cancer, with the latter being accompanied by an editorial. Both journal articles were coauthored by UHCOP faculty members Michael Johnson, Ph.D., who also served as Goyal's graduate advisor, Hua Chen, M.D., Ph.D., and Susan Abughosh, Ph.D., and UHCOP adjunct faculty member/UTHealth Houston McGovern Medical School faculty member and chair Holly Holmes, M.D., M.S., AGSF, and RTI colleague and vice president of health economics Sean Candrilli, Ph.D.