Bortezomib in previously treated phosphatase and tension homology‐deficient patients with advanced intrahepatic cholangiocarcinoma: An open‐label, prospective and single‐centre phase II trial

Abstract Introduction Intrahepatic cholangiocarcinoma (ICC) is characterized by a dismal prognosis with limited therapeutic alternatives. To explore phosphatase and tension homolog (PTEN) as a biomarker for proteasome inhibition in ICC, we conducted a phase II trial to assess the second‐line efficacy of bortezomib in PTEN‐deficient advanced ICC patients. Methods A total of 130 patients with advanced ICC in our centre were screened by PTEN immunohistochemical staining between 1 July 2017, and 31 December 2021, and 16 patients were ultimately enrolled and treated with single‐agent bortezomib 1.3 mg/m2 on days 1, 4, 8 and 11 of a 21‐day cycle. The primary endpoint was the objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors v1.1. Results The median follow‐up was 6.55 months (95% confidence interval [CI]: 0.7–19.9 months). Among the 16 enrolled patients, the ORR was 18.75% (3/16) and the disease control rate was 43.75% (7/16). The median progress‐free survival was 2.95 months (95% CI: 2.1–5.1 months) and the median overall survival (mOS) was 7.2 months (95% CI: 0.7–21.6 months) in the intent‐to‐treat‐patients. Treatment‐related adverse events of any grade were reported in 16 patients, with thrombopenia being the most common toxicity. Patients with PTEN staining scores of 0 were more likely to benefit from bortezomib than those with staining scores > 0. Conclusions Bortezomib yielded an encouraging objective response and a favourable OS as a second‐line agent in PTEN‐deficient ICC patients. Our findings suggest bortezomib as a promising therapeutic option for patients with PTEN‐deficient ICC. Highlights There is a limited strategy for the second‐line option of intrahepatic cholangiocarcinoma (ICC). This investigator‐initiated phase 2 study evaluated bortezomib in ICC patients with phosphatase and tension homology deficiency. The overall response rate was 18.75% and the overall survival was 7.2 months in the intent‐to‐treat cohort. These results justify further developing bortezomib in ICC patients with PTEN deficiency.