141P Impact of pembrolizumab versus chemotherapy on health-related quality of life in patients with metastatic triple negative breast cancer

Clinical trials of immunotherapy in triple-negative breast cancer

Purpose

Immunotherapy has started to transform the treatment of triple-negative breast cancer (TNBC), in part due to the unique immunogenicity of this breast cancer subtype. This review summarizes clinical studies of immunotherapy in advanced and early-stage TNBC.

Findings

Initial studies of checkpoint blockade monotherapy demonstrated occasional responses, especially in patients with untreated programmed death-ligand 1 (PD-L1) positive advanced TNBC, but failed to confirm a survival advantage over chemotherapy. Nonetheless, pembrolizumab monotherapy has tumor agnostic approval for microsatellite instability-high or high tumor mutational burden cancers, and thus can be considered for select patients with advanced TNBC. Combination chemoimmunotherapy approaches have been more successful, and pembrolizumab is approved for PD-L1 positive advanced TNBC in combination with chemotherapy. This success has been translated to the curative setting, where pembrolizumab is now approved in combination with neoadjuvant chemotherapy for high-risk early-stage TNBC.

Conclusion

Immunotherapy has been a welcome addition to the growing armamentarium for TNBC, but responses remain limited to a subset of patients. Innovative strategies are under investigation in an attempt to induce immune responses in resistant tumors—with regimens incorporating small-molecule inhibitors, novel immune checkpoint targets, and intratumoral injections that directly alter the tumor microenvironment. As the focus shifts toward the use of immunotherapy for early-stage TNBC, it will be critical to identify those who derive the most benefit from treatment, given the potential for irreversible autoimmune toxicity and the lack of predictive accuracy of PD-L1 expression in the early-stage setting.

Economic and Humanistic Burden of Triple-Negative Breast Cancer: A Systematic Literature Review

BACKGROUND

Triple-negative breast cancer (TNBC) accounts for 10-20% of all breast cancers (BCs). It is more commonly diagnosed in younger women and often has a less favorable prognosis compared with other BC subtypes.

OBJECTIVE

The objective of this study was to provide a literature-based extensive overview of the economic and humanistic burden of TNBC to assist medical decisions for healthcare payers, providers, and patients.

METHODS

A systematic literature review was performed using multiple databases, including EMBASE, MEDLINE, Econlit, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews, from database inception to 16 May 2021. In addition, a targeted search was performed in the Northern Light Life Sciences Conference Abstracts database from 2016 through June 2021. The bibliographies of included articles were reviewed to identify other potentially relevant publications. Quality assessment of the included studies was conducted.

RESULTS

The review identified 19 studies assessing the economic burden and 10 studies assessing the humanistic burden of TNBC. Studies varied widely in study design, settings, patient populations, and time horizons. The estimates of mean per-patient annual direct medical costs ranged from around $20,000 to over $100,000 in stage I-III TNBC and from $100,000 to $300,000 in stage IV TNBC. Healthcare costs and resource utilization increased significantly with disease recurrence, progression, and increased cancer stage or line of therapy. Compared with the costs of systemic anticancer therapy, cancer management costs comprised a larger portion of total direct costs. The estimates of indirect costs due to productivity loss ranged from $207 to $1573 per patient per month (all costs presented above were adjusted to 2021 US dollars). Cancer recurrence led to significantly reduced productivity and greater rates of leaving the workforce. A rapid deterioration of health utility associated with disease progression was observed in TNBC patients. Treatment with pembrolizumab or talazoparib showed significantly greater improvements in health-related quality of life (HRQoL) compared with chemotherapy, as measured by EORTC QLQ-C30, QLQ-BR23, and FACT-B.

CONCLUSION

TNBC is associated with a substantial economic burden on healthcare systems and societies and considerably reduced productivity and HRQoL for patients. This study synthesized the published literature on the economic and humanistic burden of TNBC and highlighted the need for continued research due to the rapidly changing landscape of TNBC care.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of breast cancer

Breast cancer has historically been a disease for which immunotherapy was largely unavailable. Recently, the use of immune checkpoint inhibitors (ICIs) in combination with chemotherapy for the treatment of advanced/metastatic triple-negative breast cancer (TNBC) has demonstrated efficacy, including longer progression-free survival and increased overall survival in subsets of patients. Based on clinical benefit in randomized trials, ICIs in combination with chemotherapy for the treatment of some patients with advanced/metastatic TNBC have been approved by the United States (US) Food and Drug Administration (FDA), expanding options for patients. Ongoing questions remain, however, about the optimal chemotherapy backbone for immunotherapy, appropriate biomarker-based selection of patients for treatment, the optimal strategy for immunotherapy treatment in earlier stage disease, and potential use in histological subtypes other than TNBC. To provide guidance to the oncology community on these and other important concerns, the Society for Immunotherapy of Cancer (SITC) convened a multidisciplinary panel of experts to develop a clinical practice guideline (CPG). The expert panel drew upon the published literature as well as their clinical experience to develop recommendations for healthcare professionals on these important aspects of immunotherapeutic treatment for breast cancer, including diagnostic testing, treatment planning, immune-related adverse events (irAEs), and patient quality of life (QOL) considerations. The evidence-based and consensus-based recommendations in this CPG are intended to give guidance to cancer care providers treating patients with breast cancer.