Impact of Pertuzumab and Ado-Trastuzumab Emtansine on Cumulative Avoidance of Recurrence Among Women Treated for Locally Advanced, Inflammatory, or Early-Stage Nonmetastatic HER2-Positive Breast Cancer in the United States.

INTRODUCTION: We assessed the impact of HER2-positive early breast cancer (EBC) treatment landscape changes following the introduction of pertuzumab and ado-trastuzumab emtansine (T-DM1) on cumulative population-level recurrences avoided since 2013 (first pertuzumab approval for EBC in the United States; US). METHODS: We constructed a multi-year epidemiologic population treatment-impact model to estimate annual recurrences between 2013 and 2031. Parameters were: BC incidence; stage I-III proportion; HER2-positive disease proportion; treatment proportions for neoadjuvant-only, adjuvant-only, and neoadjuvant-adjuvant continuation; and therapeutic agent proportions within each of those settings (chemotherapy only, trastuzumab ± chemotherapy, pertuzumab with trastuzumab ± chemotherapy, or T-DM1). The primary endpoint was cumulative recurrences, estimated by incorporating extrapolated clinical trial data for each regimen of interest into the model under four scenarios. RESULTS: Approximately 889,057 women were predicted to be diagnosed with stage I-III HER2-positive BC from 2006 to 2031 in the US and potentially indicated for HER2-targeted treatment. In steady-state equilibrium, the model estimated that real-world utilization of pertuzumab and T-DM1 will reduce the population-level number of recurrences by approximately 32%, with 7226 recurrences predicted in 2031 based on current utilization rates. In different modeled scenarios, use of neoadjuvant pertuzumab, continuation of pertuzumab in the adjuvant setting, and T-DM1 in the adjuvant setting in women with residual disease after neoadjuvant treatment were all predicted to reduce the number of recurrences. CONCLUSION: Given the improvement of HER2-targeted treatments, alongside increases in BC disease burden, we expect that the population-level impact of HER2-targeted treatments will accelerate over the next decade. Our results suggest that utilization of HER2-targeted treatments in the US has the potential to change the epidemiology of HER2-positive EBC by preventing a substantial number of women from experiencing disease recurrence. These improvements may help to inform our understanding of the future disease and economic burden of HER2-positive BC in the US.

We predicted whether two treatments for a type of breast cancer called "HER2-positive," that had not yet spread from the breast, could be used to avoid the cancer coming back in women in the United States (US), using computer modeling. The model estimated that approximately 889,057 women were predicted to be diagnosed with this type of breast cancer from 2006 to 2031, and that use of the treatments pertuzumab and ado-trastuzumab emtansine (T-DM1) would reduce the number of breast cancers that came back by around 32%. Treating with pertuzumab before surgery, continuing pertuzumab treatment after surgery, and giving T-DM1 after surgery (in the event that some of the breast cancer remained after being treated before surgery) were all predicted to reduce the number of breast cancers that come back. Overall, we expect use of pertuzumab and T-DM1 to keep lowering the number of breast cancers that come back over the next decade in the US.

Assessment of the Cost-Effectiveness of HER2-Targeted Treatment Pathways in the Neoadjuvant Treatment of High-Risk HER2-Positive Early-Stage Breast Cancer.

INTRODUCTION: This study aims to assess differences in costs and benefits of treatment strategies for high-risk human epidermal growth factor receptor 2 positive (HER2+) early-stage breast cancer (ESBC). METHODS: We used a hybrid decision-tree/Markov model to simulate costs and outcomes across six health states: Invasive disease-free, non-metastatic recurrence, remission, first-line and second-line metastatic cancer, and death. We considered several strategies, defined by four attributes: (1) Neoadjuvant targeted therapy (infused pertuzumab and trastuzumab (PH) versus subcutaneous fixed-dose combination (FDC) of pertuzumab and trastuzumab versus trastuzumab alone (H)); (2) adjuvant targeted therapy if pathological complete response (pCR) is achieved (PH, FDC, or H); (3) adjuvant targeted therapy (T-DM1 or H) in the case of residual disease (RD); and (4) use of branded or biosimilar H. Transition probabilities were derived from relevant clinical trials. We included drug costs and costs associated with adverse events and administration. Health state utilities were obtained from clinical trials and the literature. RESULTS: Strategies not containing T-DM1 were dominated (worse outcomes and greater costs) by strategies containing T-DM1. Among strategies with pertuzumab continuation in the case of pCR and T-DM1 in the case of RD, use of FDC was dominant (equivalent outcomes and lower costs), relative to strategies using infused therapies, regardless of biosimilar versus branded trastuzumab. Adjuvant continuation of FDC was also cost-effective (better outcomes at reasonable cost increases) relative to strategies which discontinued pertuzumab following pCR. CONCLUSION: Dual targeted therapy via FDC (with transition to T-DM1 in the case of RD) is a cost-effective treatment strategy in high-risk HER2+ ESBC.

HER2-Positive Metastatic Breast Cancer: A Retrospective Cohort Study of Healthcare Costs in the Targeted-Therapy Age.

INTRODUCTION: Claims data (IBM MarketScan Commercial and MarketScan Medicare Supplemental databases) from June 30, 2011 to September 30, 2017 were used to evaluate the cost impact of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) in this retrospective cohort study. METHODS: The primary analysis compared short-term costs for patients diagnosed with HER2+ MBC at least 180 days after the end of first HER2-targeted treatment (MBC+ cohort) versus a propensity score matched cohort of patients with breast cancer who did not develop MBC (MBC- cohort). A pseudo-post period for patients in the HER2+ MBC- cohort was defined by indexing to the HER2+ treatment completion-MBC diagnosis time interval of the matched pair in the HER2+ MBC+ cohort; we then compared average monthly cost differences between these groups for the year preceding and following MBC diagnosis. In secondary analyses, we estimated medium-term aggregate and categorical healthcare costs for patients with HER2+ MBC up to 3 years post-diagnosis. RESULTS: In the short-term primary analysis, costs for the HER2+ MBC+ and HER2+ MBC- cohorts were largely comparable in the year preceding MBC diagnosis. Monthly direct costs were significantly higher for the HER2+ MBC+ cohort in the months immediately preceding MBC diagnosis, with differences in the range of $500-5000. Following diagnosis, total monthly costs were $13,000-34,000 higher for patients in the HER2+ MBC+ cohort vs. the HER2+ MBC- cohort. In the medium-term secondary analysis, mean per patient total costs were $218,171 [standard error (SE) $5450] in the first year following MBC diagnosis and $412,903 (SE $13,034) cumulatively over 3 years following diagnosis (among patients with complete follow-up). Primary cost contributors were outpatient visits ($195,162; SE $8043) and HER2-targeted therapy drug costs ($177,489; SE $8120). CONCLUSIONS: HER2+ MBC is associated with high short-term and medium-term direct healthcare costs. These could be alleviated with early diagnosis and optimal standard-of-care treatment for early breast cancer, which can significantly reduce the risk of recurrence.