Lorlatinib Induces Durable Disease Stabilization in a Pancreatic Cancer Patient with a ROS1 p.L1950F Mutation: Case Report

<b><i>Introduction:</i></b> The prognosis of pancreatic cancer has improved only modestly in recent years. This is partly due to the lack of development in precision oncology including immune oncology in this entity. Rearrangements of the proto-oncogene tyrosine protein kinase <i>ROS1</i> gene represent driver alterations found especially in lung cancer. Tyrosine kinase inhibitors (TKI) with activity against ROS1 including lorlatinib substantially improved the outcome of this patient population. Anecdotal evidence reports treatment of pancreatic cancer harboring <i>ROS1</i> fusions with ROS1 TKI, but data concerning treatment of patients with <i>ROS1</i> point mutations are lacking. <b><i>Case Presentation:</i></b> This case describes a pancreatic cancer patient harboring a <i>ROS1</i> point mutation that occurred without an underlying <i>ROS1</i> rearrangement and thus not in the resistance situation. The heavily pretreated patient showed a strong decrease of the tumor biomarkers (CA19-9 and CEA) and radiologically a durable stable disease to the targeted treatment with lorlatinib, thereby achieving a progression-free survival of 12 months. <b><i>Conclusion:</i></b> Our data are the first to show a clinical benefit from targeted treatment with ROS1 TKI in a cancer patient with a thus far undescribed <i>ROS1</i> point mutation without a concomitant <i>ROS1</i> rearrangement. Furthermore, they indicate that <i>ROS1</i> could be an oncogenic driver in pancreatic cancer. This subgroup could be eligible for targeted treatments, which may contribute to the urgently needed improvement in patient outcome.