The FDA granted ado-trastuzumab emtansine breakthrough therapy designation for the adjuvant treatment of patients with HER2-positive early breast cancer who have residual disease after neoadjuvant treatment.
Ado-trastuzumab emtansine (Kadcyla, Genentech) is an antibody-drug conjugate — composed of two anticancer agents using a stable linker, the HER2-targeting agent trastuzumab and the chemotherapy agent DM1 — engineered to deliver chemotherapy directly to HER2-positive cancer cells, thereby limiting damage to healthy tissue.
The FDA’s decision was based, in part, on data from the phase 3 KATHERINE study — presented at San Antonio Breast Cancer Symposium in December — which included 1,486 patients with HER2-positive early cancer who had residual disease following neoadjuvant treatment.
As HemOnc Today previously reported, results showed adjuvant ado-trastuzumab emtansine significantly improved invasive DFS by 50% (HR = 0.5, 95% CI 0.39-0.64) compared with trastuzumab (Herceptin, Genentech).
Overall, 88.3% of patients treated with ado-trastuzumab emtansine did not experience breast cancer recurrence at 3 years compared with 77% of patients treated with trastuzumab.
The most common grade 3 to grade 4 adverse events associated with ado-trastuzumab emtansine included decreased platelet count; high blood pressure; radiation-induced skin injury; numbness, tingling or pain in the hands or feet; decreased neutrophil count; low blood potassium level; fatigue and decrease in red blood cells.
The FDA is reviewing the application under the Real-Time Oncology Review and Assessment Aid pilot programs, which aim to explore a more efficient review process to ensure safe and effective treatments are available to patients as soon as possible.
“Kadcyla was granted breakthrough therapy designation and is also the first Genentech medicine to be reviewed under the FDA’s Real-Time Oncology Review pilot program; both FDA initiatives aim to expedite reviews and bring medicines to patients sooner,” Sandra Horning, MD, chief medical officer and head of global product development at Genentech, said in a press release. “We are working closely with the FDA to bring Kadcyla to people with HER2-positive early breast cancer who have residual disease after neoadjuvant therapy as early as possible.”