diff --git a/handwritten/bigquery-storage/package.json b/handwritten/bigquery-storage/package.json
index a095062f6e3..76514c7021a 100644
--- a/handwritten/bigquery-storage/package.json
+++ b/handwritten/bigquery-storage/package.json
@@ -35,7 +35,6 @@
     "@google-cloud/precise-date": "^5.0.0",
     "apache-arrow": "^21.0.0",
     "core-js": "^3.41.0",
-    "extend": "^3.0.2",
     "google-auth-library": "^10.0.0",
     "google-gax": "^5.0.0",
     "long": "^5.2.0"
@@ -45,7 +44,6 @@
   },
   "devDependencies": {
     "@google-cloud/bigquery": "^8.0.0",
-    "@types/extend": "^3.0.4",
     "@types/mocha": "^10.0.10",
     "@types/node": "^22.13.14",
     "@types/sinon": "^17.0.4",
diff --git a/handwritten/bigquery-storage/src/managedwriter/encoder.ts b/handwritten/bigquery-storage/src/managedwriter/encoder.ts
index f3172339eda..118620e9706 100644
--- a/handwritten/bigquery-storage/src/managedwriter/encoder.ts
+++ b/handwritten/bigquery-storage/src/managedwriter/encoder.ts
@@ -19,7 +19,6 @@ import {
   isProtoCompatible,
   normalizeDescriptor,
 } from '../adapt/proto';
-import * as extend from 'extend';
 import {JSONObject, JSONValue} from './json_writer';
 import {PreciseDate} from '@google-cloud/precise-date';
 
@@ -94,7 +93,7 @@ export class JSONEncoder {
   }
 
   private convertRow(source: JSONObject, ptype: protobuf.Type): JSONObject {
-    const row = extend(true, {}, source);
+    const row = structuredClone(source);
     const keys = Object.keys(row).map(key => {
       if (!isProtoCompatible(key)) {
         const newFieldName = generatePlaceholderFieldName(key);