diff --git a/fastapi_utils/cbv.py b/fastapi_utils/cbv.py
index 231325c..0f1e881 100644
--- a/fastapi_utils/cbv.py
+++ b/fastapi_utils/cbv.py
@@ -1,4 +1,6 @@
+import functools
 import inspect
+import sys
 from typing import (
     Any,
     Callable,
@@ -16,6 +18,9 @@
 from fastapi.routing import APIRoute
 from starlette.routing import Route, WebSocketRoute
 
+if sys.version_info >= (3, 9, 0):
+    get_type_hints = functools.partial(get_type_hints, include_extras=True)
+
 PYDANTIC_VERSION = pydantic.VERSION
 if PYDANTIC_VERSION[0] == "2":
     from typing_inspect import is_classvar
@@ -74,7 +79,7 @@ def _init_cbv(cls: Type[Any], instance: Any = None) -> None:
     ]
 
     dependency_names: List[str] = []
-    for name, hint in get_type_hints(cls).items():
+    for name, hint in get_type_hints(cls, include_extras=True).items():
         if is_classvar(hint):
             continue
         parameter_kwargs = {"default": getattr(cls, name, Ellipsis)}