HER2+ Treatment in the Era of Biosimilars, Clinical Pathways, & Precision Medicine

In a Managed Care Learning Network session, Adam M Brufsky, MD, PhD, and Edward Li, PharmD, MPH, outlined the clinical and cost implication of HER2+ breast cancer treatment in the era of biosimilars, clinical pathways, and precision medicine.

Dr Brufsky, professor of medicine and associate chief of the division of hematology/oncology, at the University of Pittsburgh School of Medicine, started the session by giving an overview of the latest clinical evidence related to the management of breast cancer using HER-directed therapies.

“Personalized therapy for HER2+ breast cancer is clearly one of the most important developments to happen in the last 20 or 30 years in cancer treatment,” Dr Brufsky said. “Adjuvant therapy for HER2+ breast cancer really has revolutionized treatment.”

He highlighted multiple trials of Herceptin (trastuzumab; Genentech), which all showed a benefit associated with use of the drug. He explained that all of the studies resulted in a substantial improvement in disease free survival and overall survival at 3 to 4 years. He also highlighted studies that supported the use of Perjeta (pertuzumab; Genentech), in combination with Herceptin, which extended positive overall survival results to 5 years.

For second-line treatments of HER2+ metastatic breast cancer, Dr Brufsky highlighted Kadcyla (ado-trastuzumab emtansine; Genentech). He explained that if disease progression occurs within 12 months of treatment then use of Kadcyla is appropriate, based on evidence from clinical trial results.

Cost-Containment Strategies

Dr Li, associate professor at the University of New England College of Pharmacy, took over the session to outline how clinical pathways, value-based guidance, and biosimilars have impacted cost-containment strategies for the treatment of HER2 breast cancer.

Dr Li explained that clinical pathways are treatment decision algorithms that emphasize the most cost-effective strategies while also taking into account the need for personalized care. However, he explained that there is a lack of published evidence supporting the use of clinical pathways in the treatment of breast cancer. He said that this commonly leads to the use of value frameworks in the breast cancer space, which are used to “describe a treatments efficacy in context with the costs.”

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Dr Li then gave an overview of health care spending on breast cancer drugs. He cited data showing that drug spending growth in oncology slowed between 2010 and 2013 due to some high cost drugs coming off of patent, which opened up the market for generic competition. However, in 2014 oncology drug spending spiked because no exclusivity patents expired and a number of high cost novel monoclonal antibodies came to the market.

According to Dr Li, biosimilars have the potential to bring spending back down again in the same way generic drugs did between 2010 and 2013.

“Now we usher in the era of biosimilars and the potential for biosimilars to actually be in that space and create some competition in that space to hopefully lower drug expenditures,” he said.

Dr Li said that the cost-savings potential of biosimilars in the United States is $44.2 billion over 10 years.

However, he said that there are numerous barriers to the implementation of biosimilars, including formulary analysis, how ordering and inventory is managed, financial analysis, and education of providers and patients.

“All of these can be boiled down into the fact that we as the stakeholders will actually determine the outcome of biosimilars,” he said.

He explained that due to financial arrangements made by stakeholders, biosimilars may not always be the cheapest option. However, he noted that their presence on the market should be enough to spur competition and bring prices down over time.

Dr Li pointed to a challenge associated with the labeling of Herceptin biosimilars that could also impact uptake. He noted that the label for Perjeta states that it can be used “in combination with trastuzumab,” but that this may be interpreted to exclude combination use with trastuzumab biosimilars. He explained that there is a scientific justification for the off-label use of biosimilar products due to the rigorous regulatory framework for their approval.

Dr Li concluded that biosimilars have the ability to improve population health management of breast cancer by lowering pricing for all trastuzumab-based products.

“From the managed care perspective, implementation of biosimilars really needs to incorporate not just the cost but the total impact and how expanding the utilization of biological products in general will affect population health,” he said.

—David Costill

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