Efficacy

Efficacy of Tukysa (tucatinib) in Breast Cancer

Tukysa (tucatinib) is a tyrosine kinase inhibitor specifically designed to target HER2, a protein that can promote the growth of cancer cells. In the setting of breast cancer, Tukysa has been shown to be effective when used in combination with trastuzumab and capecitabine for the treatment of adult patients with advanced unresectable or metastatic HER2-positive breast cancer, including patients who have received previous anti-HER2 therapies. The efficacy of Tukysa was evaluated in a pivotal trial known as HER2CLIMB, which demonstrated a significant improvement in progression-free survival (PFS) and overall survival (OS) compared to trastuzumab and capecitabine alone.

In this trial, patients treated with the combination including Tukysa showed a median PFS of 7.8 months compared to 5.6 months for patients receiving trastuzumab and capecitabine without Tukysa. Furthermore, the median OS was also extended with the addition of Tukysa, indicating a clear benefit in terms of both delaying disease progression and extending the lives of patients with HER2-positive metastatic breast cancer.

Efficacy of Margenza (margetuximab-cmkb) in Breast Cancer

Margenza (margetuximab-cmkb) is a monoclonal antibody that is engineered to target the HER2 protein on the surface of cancer cells, similar to trastuzumab, but with alterations intended to enhance the engagement of the immune system. It is approved for use in combination with chemotherapy for the treatment of adult patients with metastatic HER2-positive breast cancer who have previously received two or more anti-HER2 regimens, at least one of which was for metastatic disease. The approval of Margenza was based on the results of the SOPHIA study, which compared the efficacy of Margenza plus chemotherapy to trastuzumab plus chemotherapy.

The SOPHIA trial showed that patients receiving Margenza in combination with chemotherapy experienced a median PFS of 5.8 months, compared to 4.9 months for those receiving the trastuzumab and chemotherapy combination. Although the improvement in PFS was modest, the results were statistically significant. Additionally, a trend toward improved OS was observed, but at the time of the analysis, these results were not yet statistically significant. Margenza offers an alternative treatment option for patients with HER2-positive metastatic breast cancer who have progressed on other therapies.