Cost-effectiveness of sacituzumab govitecan in hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer

Cost-effectiveness of sacituzumab govitecan for hormone receptor-positive human epidermal growth factor receptor 2-negative metastatic breast cancer based on the EVER-132-002 trial in China

BACKGROUND

The EVER-132-002 trial demonstrated the significant efficacy and manageable safety of sacituzumab govitecan in hormone receptor-positive human epidermal growth factor receptor 2-negative (HR + HER2-) metastatic breast cancer. This study evaluated the cost-effectiveness of sacituzumab govitecan compared with chemotherapy from the Chinese healthcare system perspective.

METHODS

A partitioned survival model at 21-day intervals over a 10-year time horizon was developed to evaluate the total cost, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) at willingness-to-pay (WTP) threshold of 3 times gross domestic product per capita ($38,042.49 per QALY). Clinical data were extracted from the EVER-132-002 trial; direct medical costs and utility values were obtained from public bid-winning databases, local charges or published literature. To determine the model's robustness, scenario, one-way, two-way and probabilistic sensitivity analyses were performed.

RESULTS

Compared with chemotherapy, sacituzumab govitecan generated an additional cost of $91,273.72, with an additional QALY of 0.43, resulted in an ICER of $211,948.62 per QALY. Patient weight was the most influential parameter on base-case results, and variations in each parameter did not substantially alter the conclusion. Probabilistic sensitivity analysis demonstrated that the probability of sacituzumab govitecan to be cost-effective was zero at the WTP threshold of $38,042.49 per QALY. Scenario analysis indicated that sacituzumab govitecan would be cost-effective versus chemotherapy only if its cost was reduced by 83% ($202.65 per unit) or more.

CONCLUSIONS

Sacituzumab govitecan might not be cost-effective compared with chemotherapy in the treatment for HR + HER2- metastatic breast cancer in China.

Sacituzumab Govitecan: A Review in Unresectable or Metastatic HR+/HER2- Breast Cancer

Sacituzumab govitecan (TRODELVY®) is a first-in-class trophoblast cell-surface antigen 2 (Trop-2)-directed antibody and topoisomerase I inhibitor conjugate that is approved globally as monotherapy for the treatment of adults with unresectable locally advanced or metastatic, hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-; defined as immunohistochemistry 0, 1+ or 2+ and in situ hybridization-negative) breast cancer who have received endocrine-based therapy and ≥ 2 additional systemic therapies in the advanced setting. In the phase III TROPiCS-02 trial, intravenous sacituzumab govitecan demonstrated statistically significant and clinically meaningful improvements in progression-free survival and overall survival compared with physician's choice of chemotherapy (capecitabine, eribulin, gemcitabine or vinorelbine) in adults with metastatic HR+/HER2- breast cancer. Sacituzumab govitecan had a generally manageable tolerability profile in these patients; the most common treatment-related grade ≥ 3 adverse events included neutropenia, diarrhoea, leukopenia, anaemia, fatigue and febrile neutropenia. Sacituzumab govitecan carries regulatory warnings for severe neutropenia and severe diarrhoea. Sacituzumab govitecan demonstrated an overall benefit in terms of health-related quality of life. Current evidence indicates that sacituzumab govitecan is an effective treatment option, with a generally manageable tolerability profile, for patients with pre-treated, unresectable locally advanced or metastatic HR+/HER2- breast cancer.

Emerging treatment approaches for triple-negative breast cancer

Approximately, 15% of global breast cancer cases are diagnosed as triple-negative breast cancer (TNBC), identified as the most aggressive subtype due to the simultaneous absence of estrogen receptor, progesterone receptor, and HER2. This characteristic renders TNBC highly aggressive and challenging to treat, as it excludes the use of effective drugs such as hormone therapy and anti-HER2 agents. In this review, we explore standard therapies and recent emerging approaches for TNBC, including PARP inhibitors, immune checkpoint inhibitors, PI3K/AKT pathway inhibitors, and cytotoxin-conjugated antibodies. The mechanism of action of these drugs and their utilization in clinical practice is explained in a pragmatic and prospective manner, contextualized within the current landscape of standard therapies for this pathology. These advancements present a promising frontier for tailored interventions with the potential to significantly improve outcomes for TNBC patients. Interestingly, while TNBC poses a complex challenge, it also serves as a paradigm and an opportunity for translational research and innovative therapies in the field of oncology.

Cost-effectiveness of trastuzumab deruxtecan for previously treated HER2-low advanced breast cancer

OBJECTIVE

The clinical efficacy and safety profile of trastuzumab deruxtecan (T-DXd) have been demonstrated in previously treated patients with human epidermal growth factor receptor 2 (HER2)-low advanced breast cancer (BC). It is, however, necessary to evaluate the value of T-DXd considering both its clinical efficacy and its cost, given that it is high. This study aimed to evaluate the cost-effectiveness of T-DXd versus chemotherapy in patients with previously treated HER2-low advanced BC.

METHODS

We used a partitioned survival model that included three mutually exclusive health states. The patients in the model were identified based on their clinical characteristics and outcomes from the DESTINY-Breast04. Probabilistic and one-way sensitivity analyses were performed to evaluate the model's robustness. Subgroup analyses were also conducted. The measures included costs, life years, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios (ICERs), incremental net health benefits (INHBs), and incremental net monetary benefits (INMBs).

RESULTS

The ICERs of T-DXd vs. chemotherapy were $83,892/QALY, $82,808/QALY, and $93,358/QALY in all HER2-low advanced BC patients, HER2-positive (HER2+) advanced BC patients and HER2-negative (HER2-) advanced BC patients, respectively. In one-way sensitivity analysis, the cost of T-DXd and hazard ratio (HR) for progression-free survival (PFS) and overall survival (OS) were also identified as key drivers. If the price of T-DXd decreased to $17.00/mg, $17.13/mg, and $14.07/mg, it would be cost-effective at a willingness to pay (WTP) threshold of $50,000/QALY in all HER2-low advanced BC patients, HER2+ advanced BC patients and HER2- advanced BC patients, respectively. At a WTP threshold of $100,000/QALY, the probability of T-DXd being cost-effective was 81.10%, 82.27%, and 73.78% compared to chemotherapy for all HER2-low advanced BC patients, HER2+ advanced BC patients and HER2- advanced BC patients, respectively. Most subgroups of patients with HER2+ disease had a cost-effectiveness probability of > 50%.

CONCLUSION

From a third-party payer's perspective in the United States, the findings of the cost-effectiveness analysis revealed that, at the current price, T-DXd is a cost-effective alternative to chemotherapy for patients with prior HER2-low advanced BC, at WTP threshold of $100,000/QALY.