AllianceRx Walgreens Prime studies the use of cyclin-dependent kinase 4/6 inhibitors in breast cancer patients

ORLANDO, Fla., May 11, 2020 /PRNewswire/ -- A recent study of metastatic breast cancer (MBC) patients, prescribed a class of drugs that interrupt malignant cell growth, revealed high rates of adherence, low side effects and low rates of patients stopping their medication. The class of drugs is known as cyclin-dependent kinase (CDK) 4/6 inhibitors. The retrospective study was conducted by AllianceRx Walgreens Prime, a leading specialty and home delivery pharmacy, in collaboration with the Duquesne University School of Pharmacy.

Breast cancer is the second most commonly diagnosed cancer in women, equaling about 30 percent of all newly diagnosed cancers in women in the United States. If unmanaged, this cancer typically spreads to the bones, brain, and lungs. The most common form of breast cancer is hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative which makes up 60 percent of all breast cancer diagnoses.

Typically, CDK 4/6 inhibitors (i.e., palbociclib, abemaciclib and ribociclib) are used in combination with aromatase inhibitors (a class of drugs used to treat breast cancer in postmenopausal women) as a first-line therapy regimen in the treatment of HR-positive, HER2-negative advanced or MBC. Together, this therapy lowers estrogen levels to prevent the spread of the disease.

While effective, if disease progression continues while on CDK 4/6 inhibitor therapy, there is limited current data that switching to another CDK 4/6-containing regimen would be beneficial. This study aimed to review and compare current CDK 4/6 inhibitors used to treat MBC on patient outcomes such as medication adherence, safety, and cost.

During the retrospective study, researchers analyzed records of 2,906 patients receiving either palbociclib, abemaciclib or ribociclib between January and October 2019. Patients were separated into several groups, including CDK 4/6 inhibitor monotherapy (400), CDK 4/6 inhibitor with another oncolytic agent (67), and CDK 4/6 inhibitor with both an oncolytic and hormone therapy (341). Most study patients (2,098) were on prescribed combination therapy with a CDK 4/6 and a hormonal therapy agent.

As part of the study, researchers reviewed prescription fill history to determine if patients were on appropriate dual therapy and were adherent to their medications; as well as discontinuation, and changes in therapy. They also evaluated patient-reported adverse effects as well as average copays among the medications and various payers.

Patient adherence based on a six-month time period was higher than average-reported oncolytic agent adherence rates in prior studies, according to Lakyn Husinka, PharmD, PGY-1 resident at AllianceRx Walgreens Prime and lead author/analyst of the study. "Over 60 percent of patients reported no side effects during the therapy time period and less than five percent discontinued their therapy."

As for cost, Husinka says the average wholesale price of these agents is over $13,000, and 9 percent of patients had a $0 copay throughout the six-month period.

"Relative to the cost of the medications, patient out-of-pocket costs were manageable due to the prescription coverage provided by managed care organizations as well as patient assistance programs," says Rick Miller, vice president of clinical and professional services at AllianceRx Walgreens Prime.

Husinka says the adverse drug event (ADE) results and average copays can aid a prescriber's decision when initiating therapy. "Since ADEs and high copay cost are barriers for patients to start or continue medications, having a better understanding of these attributes can help tailor agent choice to the patient," she says. "Additionally, having a better understanding of ADEs and adherence barriers experienced by patients prescribed one of the study medications will aid clinicians during patient interactions to help address and decrease these patient challenges."

She adds: "Since these medications are considered first-line agents in metastatic breast cancer due to efficacy, it is important to have positive outcomes in terms of safety, adherence and cost."

About AllianceRx Walgreens Prime
AllianceRx Walgreens Prime ( is a specialty and home delivery pharmacy that strives to provide exceptional care throughout a patient's treatment journey with the medications they need every day. Formed in 2017 through a collaboration between Walgreens, one of the nation's largest chain drug stores, and Prime Therapeutics, a leading pharmacy benefit manager, the company offers tools and resources for patients, providers and health plans to deliver the optimal health outcomes. The company is headquartered in Orlando, Fla. and its pharmacies are accredited by several national pharmacy accreditation services.

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Adrienne Foley
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SOURCE AllianceRx Walgreens Prime