Dr. Marshall on Early Data With Trastuzumab Deruxtecan in HER2+ CRC

John L. Marshall, MD, chief of the Division of Hematology/Oncology and a professor of Medicine and Oncology at Lombardi Comprehensive Cancer Center, as well as the director of the Otto J. Ruesch Center for the Cure of Gastrointestinal Cancer, discusses early data seen with fam-trastuzumab deruxtecan-nxki (Enhertu) in the treatment of patients with HER2-positive colorectal cancer (CRC) from the phase 2 DESTINY-CRC01 trial (NCT03384940).

Several important lessons have been learned with regard to HER2 positivity in patients with CRC, Marshall says. As more molecular profiling is performed, many are finding that patients with CRC are not HER2 positive; however, according to Marshall, this is because providers are not looking in the right patients. For example, patients who have RAS wild-type and BRAF wild-type disease have been found to be HER2 positive.

Additionally, HER2 positivity is measured the same way in patients with CRC as in other tumor types, through an immunohistochemistry score of 3+ or 2+ and FISH positivity, Marshall adds. Moreover, ERBB2 overexpression can also be utilized to identify HER2 positivity through genetic testing.

With this in mind, early results from the DESTINY-CRC01 trial demonstrated that definite responses are being observed in this patient population, Marshall notes. The full dataset have not read out yet, but if the positive results seen thus far are confirmed, another treatment option for patients with HER2-positive CRC will be added to the armamentarium, Marshall concludes.