257P Health-related quality of life (HRQoL) in the ASCENT study of sacituzumab govitecan (SG) in metastatic triple-negative breast cancer (mTNBC)

Cost-benefit evaluation of advanced therapy lines in metastatic triple-negative breast cancer in Germany

BACKGROUND

Triple-negative breast cancer (TNBC) is responsible for 10-20% cases of breast cancer and is resulting in rising healthcare costs. Thus, health-economic evaluations are needed to relate clinical outcomes and costs of treatment options and to provide recommendations of action from a health-economic perspective.

METHODS

We investigated the cost-benefit-ratio of approved treatment options in metastatic TNBC in Germany by applying the efficiency frontier approach. These included sacituzumab-govitecan (SG), eribulin, vinorelbine, and capecitabine. Clinical benefit was measured as (i) median overall survival (mOS) and (ii) health-related quality of life (HRQoL) in terms of time to symptom worsening (TSW). To assess medical benefits, literature was systematically reviewed in PubMed for (i) and (ii), respectively. Treatment costs were calculated considering annual direct outpatient treatment costs from a statutory healthcare payer perspective. It was intended that both, (i) and (ii), yield an efficiency frontier.

RESULTS

Annual direct outpatient treatment costs amounted to EUR 176,415.21 (SG), EUR 47,414.14 (eribulin), EUR 13,711.35 (vinorelbine), and EUR 3,718.84 (capecitabine). Systematic literature review of (i) and statistical analysis resulted in OS values of 14.3, 9.56, 9.44, and 7.46 months, respectively. Capecitabine, vinorelbine, and SG are part of the efficiency frontier including OS. The highest additional benefit per additional cost was determined for vinorelbine, followed by SG. Systematic review of (ii) revealed that no TSW data of TNBC patients receiving vinorelbine were available, preventing the presentation of an efficiency frontier including HRQoL.

CONCLUSIONS

Vinorelbine is most cost-effective, followed by SG. Health-economic evaluations support decision-makers to assess treatment options within one indication area. In Germany, the efficiency frontier can provide decision support for the pricing of innovative interventions. Results of our analysis may thus guide reimbursement determination.

Early-stage triple negative breast cancer: the therapeutic role of immunotherapy and the prognostic value of pathological complete response

Triple negative breast cancer (TNBC) represents an aggressive disease associated with a high risk of recurrence after curative treatment and a poor prognosis in the metastatic setting. Chemotherapy was for years the only treatment available in the early and metastatic setting, due to the lack of actionable targets. Clinical practice has changed following the results obtained with the addition of immunotherapy to standard chemotherapy, the development of novel drugs [i.e. antibody-drug conjugates (ADCs)], and the use of targeted treatments for patients carrying germline pathogenic breast cancer susceptibility genes (BRCA) 1 or BRCA 2 variants. The treatment of early-stage disease has had a shift in clinical practice since July 2021, after the Food and Drug Administration (FDA) approval of pembrolizumab in association with chemotherapy as neoadjuvant treatment for TNBC and as a single agent in the subsequent adjuvant setting. This intensive treatment based on the combination of a poly-chemotherapy and an immune checkpoint inhibitor (ICI) led to the improvement of short- and long-term outcomes, but it has highlighted some new unmet clinical needs in the treatment of early-stage TNBC: the selection of the most effective adjuvant therapy and the integration of pembrolizumab with other therapeutic strategies [capecitabine, poly(ADP-ribose) polymerase (PARP) inhibitors] based on the achievement of pathologic complete response (pCR); the identification of predictive biomarkers to select patients who could most benefit from the addition of ICI, to minimize toxicities and to maximize outcomes; the possibility of de-escalating chemotherapy in favor of immune-combo or novel agents, such as ADCs; the role of immunotherapy in estrogen receptor (ER)-low patients. The advent of immunotherapy not only addresses current challenges in TNBC treatment but also holds the promise of a radical transformation in its therapeutic paradigm, enhancing significantly clinical outcomes and offering new perspectives for patients grappling with this aggressive form of breast cancer.

In vitro breast cancer models for studying mechanisms of resistance to endocrine therapy

The development of endocrine resistance is a common reason for the failure of endocrine therapies in hormone receptor-positive breast cancer. This review provides an overview of the different types of in vitro models that have been developed as tools for studying endocrine resistance. In vitro models include cell lines that have been rendered endocrine-resistant by ex vivo treatment; cell lines with de novo resistance mechanisms, including genetic alterations; three-dimensional (3D) spheroid, co-culture, and mammosphere techniques; and patient-derived organoid models. In each case, the key discoveries, different analysis strategies that are suitable, and strengths and weaknesses are discussed. Certain recently developed methodologies that can be used to further characterize the biological changes involved in endocrine resistance are then emphasized, along with a commentary on the types of research outcomes that using these techniques can support. Finally, a discussion anticipates how these recent developments will shape future trends in the field. We hope this overview will serve as a useful resource for investigators that are interested in understanding and testing hypotheses related to mechanisms of endocrine therapy resistance.

New antibody-drug conjugates (ADCs) in breast cancer—an overview of ADCs recently approved and in later stages of development

Antibody-drug conjugates (ADCs) have changed the treatment of breast cancer (BC) in more recent years. BC is a heterogenous group of malignancies with a broad range of histopathological characteristics. ADCs represent a class of therapeutics that combines an antigen-specific antibody backbone bound to a potent cytotoxic agent (the payload), via a linker, contributing to an improved therapeutic index. Currently, three ADCs received approval by the US Food and Drug Administration (FDA) and are in routine clinical use in different treatment settings; many more ADCs are in earlier and later stages of development, and their future approval will improve treatment options for patients with advanced but potentially also early-stage BC over time. Just recently, the results of three phase 3 trials (ASCENT, TULIP, and DESTINY-Breast03) evaluating sacituzumab govitecan (SG), trastuzumab duocarmazine, and trastuzumab deruxtecan (T-DXd) in different treatment settings were presented and showed promising results. This overview focuses on the newer ADCs, including T-DXd and SG, their pharmacology, mechanisms of action, and relevant studies. In addition, the latest results from trials investigating some newer ADCs, in further stages of development are presented.

A New Kid on the Block: Sacituzumab Govitecan for the Treatment of Breast Cancer and Other Solid Tumors

Human trophoblast cell-surface antigen-2 (Trop-2) is a membrane glycoprotein involved in cell proliferation and motility, frequently overexpressed in epithelial tumors. Thus, it represents an attractive target for anticancer therapies. Sacituzumab govitecan (SG) is a third-generation antibody-drug conjugate, consisting of an anti-Trop-2 monoclonal antibody (hRS7), a hydrolyzable linker, and a cytotoxin (SN38), which inhibits topoisomerase 1. Specific pharmacological features, such as the high antibody to payload ratio, the ultra-toxic nature of SN38, and the capacity to kill surrounding tumor cells (the bystander effect), make SG a very promising drug for cancer treatment. Indeed, unprecedented results have been observed with SG in patients with heavily pretreated advanced triple-negative breast cancer and urothelial carcinomas, and the drug has already received approval for these indications. These results are coupled with a manageable toxicity profile, with neutropenia and diarrhea as the most frequent adverse events, mainly of grades 1-2. While several trials are exploring SG activity in different tumor types and settings, potential biomarkers of response are under investigation. Among these, Trop-2 overexpression and the presence of BRCA1/2 mutations seem to be the most promising. We review the available literature concerning SG, with a focus on its toxicity spectrum and possible biomarkers of its response.