diff --git a/numpyro/optim.py b/numpyro/optim.py
index d58f7c739..8d1717b16 100644
--- a/numpyro/optim.py
+++ b/numpyro/optim.py
@@ -9,7 +9,7 @@
 
 from collections import namedtuple
 from collections.abc import Callable
-from typing import Any, Generic, TypeVar
+from typing import Any
 
 import jax
 from jax import jacfwd, lax, value_and_grad
@@ -32,8 +32,8 @@
     "SM3",
 ]
 
-_Params = TypeVar("_Params")
-_OptState = TypeVar("_OptState")
+_Params = Any
+_OptState = Any
 _IterOptState = tuple[ArrayLike, _OptState]
 
 
@@ -50,7 +50,7 @@ def _wrapper(x):
         return value_and_grad(f, has_aux=True)(x)
 
 
-class _NumPyroOptim(Generic[_Params, _OptState]):
+class _NumPyroOptim(object):
     def __init__(self, optim_fn: Callable, *args, **kwargs) -> None:
         self.init_fn: Callable[[_Params], _IterOptState]
         self.update_fn: Callable[[ArrayLike, _Params, _OptState], _OptState]
@@ -258,7 +258,7 @@ def update_fn(
         # we don't use update_fn in Minimize, so let it do nothing
         return opt_state
 
-    def get_params(opt_state: _MinimizeState) -> _Params:  # type: ignore[type-var]
+    def get_params(opt_state: _MinimizeState) -> _Params:
         flat_params, unravel_fn = opt_state
         return unravel_fn(flat_params)