Exceptional sustained long-term complete response to Tepotinib in a MET-amplified advanced intrahepatic biliary tract cancer failing Durvalumab plus Cisplatin and Gemcitabine.

Background: Biliary tract cancers (BTCs) are a diverse group of malignancies with varied genetic backgrounds. The prevalence of intrahepatic cholangiocarcinoma (iCC) is increasing, particularly in Western countries. Despite advancements in treatments, the prognosis for BTC remains poor. Recent molecular profiling has revealed that up to 40% of iCC cases have targetable genetic alterations. MET amplification, although rare, presents a significant target for therapy.

Case presentation: A 25-year-old female with a history of ulcerative colitis presented with shoulder pain and a positron emission tomography-computed tomography (PET-CT) scan revealed an enlarged liver and multiple metastases. Histopathological analysis diagnosed poorly differentiated adenocarcinoma. First-line therapy with Cisplatin, Gemcitabine, and Durvalumab resulted in disease progression. Molecular profiling identified a TP53 mutation and MET amplification. Based on these findings, Tepotinib was initiated. Tepotinib treatment led to a significant reduction in tumor size and normalization of CA 19-9 levels within 2 months, achieving a complete metabolic remission lasting up to 17 months. The treatment was well tolerated with minimal side effects.

Discussion: MET-amplified BTCs are exceedingly rare, and evidence for targeted treatment is limited. This case demonstrates the efficacy of Tepotinib in a young patient with MET-amplified iCC, showing a long-term response and suggesting a potential new standard treatment option for this molecularly defined entity. This case also highlights the aggressive nature of MET-amplified tumors and the need for targeted second-line therapies.

Conclusion: Tepotinib showed remarkable efficacy in treating MET-amplified intrahepatic cholangiocarcinoma, underscoring the importance of molecular profiling in BTCs and suggesting a potential new therapeutic approach for this rare cancer subtype.