HER2-positive breast cancers, affecting 10-20% of cases, overexpress the HER2 receptor, fueling aggressive growth. A groundbreaking phase 3 trial highlights the superior efficacy of trastuzumab deruxtecan over standard therapies.
Breast cancer remains the leading cause of cancer death among women and the most commonly diagnosed cancer worldwide since 2021. Ongoing research, including AI-driven diagnostics, advances detection and treatment.
In 10-20% of cases, tumors are HER2-positive, featuring excessive HER2 receptors on cell surfaces. These receptors, activated by growth factors, drive rapid proliferation, evade apoptosis, and promote angiogenesis for nutrient supply.
HER2 overexpression makes it a prime therapeutic target. Routine testing guides a tiered treatment approach: monoclonal antibodies like trastuzumab (Herceptin) block HER2 activation, paired with cytotoxics.
First-line options combine trastuzumab with chemotherapy. For suboptimal responses, trastuzumab emtansine (T-DM1) disrupts microtubule assembly, a key cytoskeletal component. If needed, trastuzumab deruxtecan—a topoisomerase inhibitor—follows.
The DESTINY-Breast03 phase 3 trial, published in the New England Journal of Medicine on March 24, 2022, repositioned trastuzumab deruxtecan earlier in treatment. It compared it directly to trastuzumab emtansine in pretreated HER2+ metastatic breast cancer patients.
Among 524 participants randomized to two arms, 75% on trastuzumab deruxtecan achieved 12-month progression-free survival, versus 38% on trastuzumab emtansine. Overall survival also improved significantly.
While trastuzumab deruxtecan carries risks like interstitial lung disease and infections, its benefits—extended survival and reduced progression risk—outweigh these in expert clinical judgment.
