Comparative effectiveness of trastuzumab emtansine versus lapatinib plus chemotherapy for HER2+ metastatic breast cancer

Third-line treatment patterns in HER2-positive metastatic breast cancer: a retrospective analysis of real-world data in Canada

There is an increasing demand for real-world data pertaining to the usage of cancer treatments, especially in settings where no standard treatment is specifically recommended. This study presents the first real-world analysis of third-line treatment patterns in HER2-positive metastatic breast cancer (mBC) patients in Canada. The purpose was to assess evolution of clinical practice and identify unmet needs in post-second-line therapy. Retrospective data from medical records of 66 patients who received third-line treatment before 31st October 2018, and data from 56 patients who received third-line treatment after this date, extracted from the Personalize My Treatment (PMT) cancer patient registry, were analyzed. In the first cohort, the study revealed heterogeneity in the third-line setting, with trastuzumab, lapatinib, and T-DM1 being the main treatment options. Even though data were collected before the wide availability of tucatinib, neratinib and trastuzumab deruxtecan in Canada, the PMT cohort revealed the emergence of new therapeutic combinations and a shift from lapatinib usage to T-DM1 choice was observed. These findings underscore the evolving nature of third-line treatment strategies in Canada, a facet that is intrinsically tied to the availability of new drugs. The absence of a consensus on post-second-line treatment highlights the pressing need for more efficient therapeutic alternatives beyond the currently available options. This study not only offers valuable insights into the present landscape of third-line treatment in Canada but validates the significance and effectiveness of the PMT registry as a tool for generating pan-Canadian real-world evidence in oncology and its capacity to provide information on evolution of therapeutic practices.

Real-World Treatment Patterns and Outcomes Following First-Line Pertuzumab and Trastuzumab Among Patients with HER2+ Metastatic Breast Cancer

INTRODUCTION

Many patients with human epidermal growth factor receptor-2-positive metastatic breast cancer (HER2+ mBC) require subsequent lines of therapy (LOTs) after being treated with pertuzumab and trastuzumab-based regimens in the first line (1L). Although the efficacy of the second-line (2L) therapies has been demonstrated in clinical trials, the real-world effectiveness of these treatments is understudied. This retrospective cohort study assessed the real-world treatment patterns and outcomes for patients with HER2+ mBC following 1L therapy with pertuzumab and trastuzumab-based regimens in the United States (US) during 2015-2019.

METHODS

Adults with HER2+ mBC in the US who initiated 1L pertuzumab and trastuzumab-based regimens between 01/01/2015 and 09/30/2019 and had ≥ 60 days of follow-up after 1L initiation were identified from the IQVIA Oncology Electronic Medical Records database. The regimens utilized in 2L following 1L pertuzumab and trastuzumab-based regimens were described. Median treatment duration and time to treatment failure were reported for 2L based on Kaplan-Meier analyses.

RESULTS

Of the 710 eligible patients who received pertuzumab and trastuzumab-based regimens in 1L (median age: 57.0 years [interquartile range: 48.0-65.0]; median follow-up: 20.3 months; median 1L duration: 15.3 months), 222 (31.3%) initiated 2L. The most common regimens in 2L were ado-trastuzumab emtansine (T-DM1)-based regimens (n = 159 [71.6%]), followed by lapatinib-based (n = 21 [9.5%]) and neratinib-based (n = 18 [8.1%]) regimens. The median treatment duration and time to treatment failure were 5.9 (95% CI: 5.0, 8.7) and 8.6 (7.3, 11.5) months, respectively, among patients initiating 2L, and 5.7 (4.7, 7.8) and 7.9 (6.5, 10.0) months among those receiving 2L T-DM1.

CONCLUSIONS

Most patients with HER2+ mBC requiring additional treatments after 1L pertuzumab and trastuzumab-based regimens utilized T-DM1 in 2L during 2015-2019. The short median treatment duration and time to treatment failure highlight an unmet need that can potentially be fulfilled by recently approved treatment options.

Survival Outcomes of Patients With Tropomyosin Receptor Kinase Fusion-Positive Cancer Receiving Larotrectinib Versus Standard of Care: A Matching-Adjusted Indirect Comparison Using Real-World Data

PURPOSE

Larotrectinib, a highly specific tropomyosin receptor kinase (TRK) inhibitor, previously demonstrated high response rates in single-arm trials of patients with TRK fusion-positive cancer, but there are limited data on comparative effectiveness against standard-of-care (SoC) regimens used in routine health care practice, before widespread adoption of TRK inhibitors as SoC for TRK fusion-positive cancers. Matching-adjusted indirect comparison, a validated methodology that balances population characteristics to facilitate cross-trial comparisons, was used to compare the overall survival (OS) of larotrectinib versus non-TRK-inhibitor SoC.

MATERIALS AND METHODS

Individual patient data from three larotrectinib trials (ClinicalTrials.gov identifiers: NCT02122913, NCT02637687, and NCT02576431) were compared with published aggregate real-world data from patients with locally advanced/metastatic TRK fusion-positive cancer identified in the Flatiron Health/Foundation Medicine database. OS was defined as the time from advanced/metastatic disease diagnosis to death. After matching population characteristics, the analyses included (1) a log-rank test of equality to test whether the two groups were similar before larotrectinib initiation; and (2) estimation of treatment effect of larotrectinib versus non-TRK-inhibitor SoC. These analyses are limited to prognostic variables available in real-world data.

RESULTS

Eighty-five larotrectinib patients and 28 non-TRK-inhibitor SoC patients were included in the analyses. After matching, log-rank testing showed no difference in baseline characteristics between the two groups (P = .31). After matching, larotrectinib was associated with a 78% lower risk of death, compared with non-TRK-inhibitor SoC (adjusted hazard ratio, 0.22 [95% CI, 0.09 to 0.52]; P = .001); median OS was 39.7 months (95% CI: 16.4, NE [not estimable]) for larotrectinib and 10.2 months (95% CI: 7.2, 14.1) for SoC.

CONCLUSION

Matching-adjusted indirect comparison analyses suggest longer OS with larotrectinib, compared with non-TRK-inhibitor SoC, in adult patients with TRK fusion-positive cancer.

Breast cancer liver metastasis: current and future treatment approaches

Nearly all fatalities arising from breast tumors are attributable to distant metastases. Breast cancer liver metastasis (BCLM) is associated with poor prognoses, with the median survival time being 2 to 3 years. Tumor intrinsic subtype directs preferential metastasis to specific organs, with HER2-enriched tumors demonstrating the highest rates of metastasis to the liver, though all subtypes can grow in the liver. There is no singular established standard-of-care for BCLM; therapeutic selection is driven by histologic and molecular hallmarks of the primary tumor or biopsied metastasis samples. Given the poor prognosis of patients with hepatic spread, pre-clinical studies are necessary to identify and evaluate promising new treatment strategies. It is critical that these laboratory studies accurately recapitulate the BCLM disease process, standard progression, and histological attributes. In this review, we summarize the histologic and molecular characteristics of BCLM, evaluate the efficacy of existing surgical and medical treatment strategies, and discuss future approaches to preclinical study of BCLM.