Michelle Muir, PharmD, University of North Carolina at Chapel Hill Eshelman School of Pharmacy, Carrboro, discusses results from a study evaluating the effectiveness and safety of generic imatinib compared to branded imatinib for patients with chronic myeloid leukemia (CML) in real-world clinical practice.

This study was presented at the 2021 ASH Annual Meeting.

Transcript

I'm excited to be speaking about our recent poster presentation at the 2021 ASH Conference. My name is Michele Muir. I am a current postdoctoral fellow at the University of North Carolina at Chapel Hill's Eshelman School of Pharmacy.

I just want to give a special thank you to the Journal of Clinical Pathways for this platform to discuss our study that was entitled "Evaluating Real-World Effectiveness, Safety, and Cost of Generic and Brand-Name Imatinib in Chronic Myeloid Leukemia."

I performed this work with Dr Benyam Muluneh in the Division of Pharmacotherapy and Experimental Therapeutics. There's Dr Chen in the Division of Pharmaceutical Outcomes and Policy, Dr Ozawa in the Division of Practice Advancement and Clinical Education. Then several pharmacy students participated in this study, Jasmine Johnson, Sitong Shu, and Melissa Mass, from UNC.

To get started, chronic myeloid leukemia, otherwise known as CML, is a hematologic malignancy that starts in the bone marrow and has considerable health and economic burden to patients.

Imatinib, our drug of interest, is an oral tyrosine kinase inhibitor that has been shown to significantly reduce CML mortality. However, the high cost of imatinib treatment has still been prohibitive for patient access, and even despite high hopes that accompanied the approval of generic imatinib in 2016, uptake has still remained quite low.

Our research question was actually inspired by the book "Bottle of Lies: The Inside Story of the Generic Drug Boom" by Katherine Eban. While the book focuses on the concerns and ethics behind generic drug manufacturing, we were intrigued to further investigate the differences between brand and generic medications.

There had also been reports of substandard quality of imatinib identified outside of the United States. Although the FDA requires that generic medications have to contain the same active ingredient as the brand, inactive ingredients can vary between formulation and products and potentiate undocumented side effects.

Additionally, the FDA inspection of generic manufacturers outside the United States had also come under scrutiny. Then, in terms of costs, generic medications theoretically should increase access in patients where cost was previously an issue or a barrier. However, when generic formulations of imatinib were approved and commercially available in the United States, out-of-pocket spending was only about 24% lower, even though the list prices were around 80% lower.

Therefore, we wanted to push the envelope and investigate the real-world effectiveness, safety, and cost of generic imatinib when compared to the branded product in our patient population.

To accomplish this analysis, we performed this study through a retrospective single-institution proof-of-principle study, where we collected chart-reviewed information and cost data from participating pharmacies.

We included patients treated at our academic medical institution that were diagnosed with CML and treated with imatinib at any time during the course of treatment. Then our primary end point included product effectiveness that was determined by the patients’ molecular response.

Then, in terms of secondary endpoints, we included product safety, and that involved things like adverse drug events, all-cause hospitalization, early treatment discontinuation. Then, lastly, we evaluated out-of-pocket costs for these patients.

Then patients were excluded from the primary end point evaluation and only included for the safety end point analysis if they were not treated with imatinib first-line and if the duration of imatinib treatment was less than 6 months.

Then, when evaluating our results, we found molecular response rates were higher at 3 and 6 months with brand-name imatinib when compared to the generic. Then, when evaluating that safety end point, brand-name imatinib had higher rates of temporary dose interruptions, while generic imatinib had higher rates of permanent discontinuation due to an adverse event.

Then, when evaluating the cost data, out-of-pocket costs among the CML patients for generic imatinib was found on average to be around 57% lower than brand-name imatinib.

In conclusion, the brand-name imatinib had achieved higher rates of molecular response and experienced higher rates of temporary dose interruptions but was less likely to be permanently discontinued due to an adverse event. Then, conversely, generic imatinib was found on average to have a 57% lower monthly out-of-pocket cost when compared to that branded product.

I will say, although further analyses of these comparisons and continuation of data collection, and even getting evaluation of demographic data, will provide a more robust assessment to compare these end points, we at least hope these findings and future findings will guide pharmaceutical policies and prescribing practices to just improve chronic myeloid leukemia patients' health and economic outcomes.

It does continue to raise the question, are brand and generic medications created equal? Brand imatinib appears to provide better clinical outcomes despite its high price tag, but is the trade-off worth it?

If further research with more patients confirms this hypothesis, we absolutely have to find a way to balance the scale of brand and generics to provide affordable access and clinical excellence to our patients.

I just want to give a shout-out and say that we appreciate the mission of the Journal of Clinical Pathways to provide a platform to improve high-quality cost-effective care. I once again want to thank my coauthors and mentors for their support and guidance in this research. Thank you.

Muir M, Johnson J, Shu S, et al. Evaluating Real-World Effectiveness and Safety of Generic and Brand-Name Imatinib in Chronic Myeloid Leukemia. Presented at the ASH Annual Meeting and Exposition; December 11-14, 2021; Atlanta, GA and Virtual. Abstract 3614.