Patient-Reported Outcomes Predictive of PFS in Patients Receiving Abemaciclib for Advanced Breast Cancer

Pretreatment patient-reported outcomes (PROs) are potential prognostic tools for patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2–) advanced breast cancer who are undergoing treatment with abemaciclib, a CDK4/6 inhibitor, according to a team of researchers based in Australia. Their findings were published in The Oncologist.

The researchers developed a model based on data from the single-arm MONARCH 1 trial, along with data from 2 other randomized trials: MONARCH 2 and MONARCH 3. The data were from a total of 1284 patients, with 900 in the treatment (abemaciclib) arms and 384 in the placebo, comparator therapy arms.

The researchers analyzed several PROs, including pain, fatigue, appetite loss, role function, and physical function, to determine their association with progression-free survival (PFS). The patient-reported outcome that came out on top was physical function. This outcome proved to be superior (c =0.55) to the Eastern Cooperative Oncology Group performance status (ECOG-PS; c =0.54) in predicting outcomes.

Another key finding from the study was that patients with low physical function who were treated with abemaciclib experienced a smaller PFS benefit than patients with intermediate or high physical function.

This information could be very useful for clinicians who are caring for patients with HR+/HER2– advanced breast cancer, as it suggests that pretreatment physical function might be an important predictor for PFS in this subgroup of patients who are likely to achieve less benefit from treatment with abemaciclib in combination with fulvestrant or a nonsteroidal aromatase inhibitor (NSAI) compared with fulvestrant or an NSAI alone.

“The present study demonstrates PROs as a simple, effective, inexpensive and independent prognostic marker for HR+/HER2– [advanced breast cancer] treated with abemaciclib, which is a patient cohort with a scarcity of prognostic markers,” the researchers wrote. “Ultimately, it will be of interest for future research to consider incorporating PROs in the development of clinical prediction models and tools, which may be able to provide patients with realistic expectations of treatment outcomes and support shared decision-making.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Badaoui S, Kichenadasse G, Rowland A, Sorich MJ, Hopkins AM. Patient-reported outcomes predict progression-free survival of patients with advanced breast cancer treated with abemaciclib. Oncologist.  Published online April 29, 2021. doi:10.1002/onco.13806