EGFR and HER3 signaling blockade in invasive mucinous lung adenocarcinoma harboring an NRG1 fusion.

Rearrangements of NRG1 have been identified in invasive mucinous adenocarcinoma of the lung (IMA), formerly referred to as mucinous bronchioloalveolar carcinoma. NRG1 ligand signals through induction of HER2-HER3 heterodimers, thus leading to PI3K-AKT pathway activation. Therefore, targeting HER2, HER3 and the downstream pathway may be a hypothesis-driven strategy for IMA with NRG1 fusion. Herein we reported two patients who benefited from lumretuzumab, a monoclonal anti-HER3 antibody, in combination of erlotinib during a clinical trial (NCT01482377). At least sixteen weeks of progression-free survival were achieved without any unacceptable toxicity.