RX Profiler: Review of Ribociclib for Advanced Hormone Receptor–Positive Breast Cancer

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Perspectives

Treatment of Advanced Breast Cancer: A Clinical Pharmacy Perspective

By Val R. Adams, PharmD, FCCP, BCOP, and Allison R. Butts, PharmD, BCOP
Dr Adams is Associate Professor, Pharmacy, Program Director, Hematology/Oncology Pharmacy Residency; Dr Butts is Hematology/Oncology Clinical Pharmacist and Adjunct Assistant Professor, Pharmacy, Comprehensive Breast Care Center, University of Kentucky HealthCare, Lexington

 

At the Markey Cancer Center in Lexington, KY, clinical pharmacists are integral members of the multidisciplinary care team, working in the clinic alongside surgical and medical oncologists, imaging specialists, radiation oncologists, pathologists, nurses, and other healthcare providers. Clinical pharmacists also have a close working relationship with specialty pharmacists who are employed by the institution. As part of the team, clinical pharmacists play a vital role in patient evaluation, education, and management. In addition, they participate in tumor boards and collaborate with the team in making treatment recommendations.

In the breast cancer clinic, the clinical pharmacist sees all patients who receive active therapy, and monitors the emergence and management of treatment-related toxicities through patient assessment and evaluation of laboratory results. During discussions with the patient, the clinical pharmacist reinforces the importance of adhering to therapy as prescribed. This is especially important for patients who receive oral chemotherapy, which is self-administered so patients may have fewer clinic visits than those who receive intravenous (IV) treatment.

A 2015 study by Parsons and colleagues showed that a pharmacist intervention significantly increased compliance with prescribing standards for oral chemotherapy compared with no pharmacist intervention regarding dose calculation (P <.0001), patient height and weight (P <.015), and other pertinent information (P <.0001).1 The study also showed that of a total of 84 pharmacist interventions, the most common interventions were dose adjustments (19%) and side-effect management (17%).1

Depending on the patient’s needs, the clinical pharmacist may also work with other staff members, such as financial counselors or social workers, to optimize patient care. Similarly, clinical pharmacists confer with specialty pharmacists to ensure that insurance issues are resolved so that the patient receives timely access to treatment.

In some cases, it may be necessary to switch therapies. When this occurs, clinical pharmacists leverage their specialized training to make treatment recommendations based on the patient’s breast cancer subtype, extent of disease, treatment history, and performance status.

As a regional referral center, Markey Cancer Center has a sizable number of patients with metastatic breast cancer, a type of cancer that is increasingly being viewed and treated as a chronic disease. In this paradigm, clinicians often start with the least toxic regimens, to offer the patient the best quality of life, for the longest duration possible. Patients may not respond to therapy over time and progress through multiple lines of treatment; therefore, it is important to closely assess their response and make an effort to prevent, identify, and manage toxicities through counseling and appropriate interventions. The multidisciplinary care model is well-suited to the coordinated, integrated care that is required for patients with advanced breast cancer, many of whom may have supportive care needs or other conditions that require medical attention by multiple clinicians.

In the clinic, patients with endocrine receptor–positive breast cancer are often initially prescribed hormonal therapy, such as aromatase inhibitors or tamoxifen. Although these drugs are administered with curative intent, a proportion of patients subsequently have disease metastases. When metastatic disease is detected, clinicians may consider targeted therapies after disease progression or in combination with endocrine therapies. For example, the kinase inhibitor palbociclib is indicated for the treatment of hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced or metastatic breast cancer, in combination with letrozole as initial endocrine-based therapy in postmenopausal women, or in combination with fulvestrant in women with disease progression after endocrine therapy.

In our experience, oral hormone and targeted therapies are generally less toxic than IV chemotherapy, making oral therapies an attractive treatment option for some patients. The consideration of treatment options depends on several factors, including performance status, access to the clinic, and the patient’s ability and willingness to tolerate side effects. Regardless of the specific therapeutic approach, treatment decisions are very much individualized to the patient.

Because patients’ tumors ultimately become resistant to hormonal treatment options, the majority of patients with advanced-stage breast cancer will receive chemotherapy at some point during the course of their disease. Many patients, especially those with slowly progressing or indolent disease, will have disease progression through multiple treatment regimens, and some patients run out of treatment options. As a result, an unmet need remains for additional therapies to treat these patients. A newly approved drug, ribociclib has shown promise in extending progression-free survival, with acceptable toxicity in patients with metastatic breast cancer.

As more treatment options for breast cancer become available, and patients receive more lines of treatment, clinicians face new challenges in optimizing breast cancer treatment. Because of the manner in which clinical trials are currently designed, it can be difficult to determine how to appropriately sequence therapies, or how to determine which combination approaches are best for patients.

Clinical pharmacists and other clinicians are increasingly looking for novel end points to provide actionable data. One such end point is the ratio of progression-free survival, which measures the time to disease progression with the current treatment versus the time to disease progression with previous treatment. Because the disease-relapse interval typically becomes progressively shorter with each successive line of therapy, clinicians seek treatment strategies that maximize progression-free intervals.

As more cancers, including breast cancer, are viewed through the lens of chronic disease, these types of data, in addition to novel and targeted therapeutic approaches, offer the best opportunity to positively impact patient outcomes.

Author Disclosure Statement
Dr Adams and Dr Butts reported no conflicts of interest.

Reference

  1. Parsons LB, Edwards K, Perez A, et al. Positive outcomes associated with a pharmacist-driven oral chemotherapy program. J Hematol Oncol Pharm. 2015;5:99-108.
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