A Phase II Study of Avelumab Monotherapy in Patients with Mismatch Repair–Deficient/Microsatellite Instability–High or POLE-Mutated Metastatic or Unresectable Colorectal Cancer
- Author:
Jwa Hoon KIM
1
;
Sun Young KIM
;
Ji Yeon BAEK
;
Yong Jun CHA
;
Joong Bae AHN
;
Han Sang KIM
;
Keun-Wook LEE
;
Ji-Won KIM
;
Tae-You KIM
;
Won Jin CHANG
;
Joon Oh PARK
;
Jihun KIM
;
Jeong Eun KIM
;
Yong Sang HONG
;
Yeul Hong KIM
;
Tae Won KIM
Author Information
- Publication Type:Original Article
- From:Cancer Research and Treatment 2020;52(4):1135-1144
- CountryRepublic of Korea
- Language:English
-
Abstract:
Purpose:We evaluated the efficacy and safety of avelumab, an anti-PD-L1 antibody, in patients with metastatic or unresectable colorectal cancer (mCRC) with mismatch repair deficiency (dMMR)/microsatellite instability-high (MSI-H) or POLE mutations.
Materials and Methods:In this prospective, open-label, multicenter phase II study, 33 patients with mCRC harboring dMMR/MSI-H or POLE mutations after failure of ≥1st-line chemotherapy received avelumab 10 mg/kg every 2 weeks. dMMR/MSI-H was confirmed with immunohistochemical staining (IHC) by loss of expression of MMR proteins or polymerase chain reaction (PCR) for microsatellite sequences. POLE mutation was confirmed by next-generation sequencing (NGS). The primary endpoint was the objective response rate (ORR) by Response Evaluation Criteria in Solid Tumors ver. 1.1.
Results:The median age was 60 years, and 78.8% were male. Thirty patients were dMMR/MSI-H and three had POLE mutations. The ORR was 24.2%, and all of the responders were dMMR/MSI-H. For 21 patients with MSI-H by PCR or NGS, the ORR was 28.6%. At a median follow-up duration of 16.3 months, median progression-free survival and overall survival were 3.9 and 13.2 months in all patients, and 8.1 months and not reached, respectively, in patients with MSI-H by PCR or NGS. Dose interruption and discontinuation due to treatment-related adverse events occurred in 4 and 2 patients, respectively, with no treatment-related deaths.
Conclusion:Avelumab displayed antitumor activity with manageable toxicity in patients with previously treated mCRC harboring dMMR/MSI-H. Diagnosis of dMMR/MSI-H with PCR or NGS could be complementary to IHC to select patients who would benefit from immunotherapy.
