Varlitinib (ASLAN001) is a reversible pan-HER inhibitor being studied in gastric, cholangiocarcinoma, breast, and colorectal cancers and is now being examined in a phase 1b/2 trial in combination with mFOLFOX for HER1/HER2 co-expressing gastric cancer (NCT03130790). The gene discussed is ERBB2; the disease is gastric cancer.