diff --git a/integration-tests/it-exporter/it-exporter-test/src/test/java/io/prometheus/metrics/it/exporter/test/ExporterIT.java b/integration-tests/it-exporter/it-exporter-test/src/test/java/io/prometheus/metrics/it/exporter/test/ExporterIT.java
index b01e6b3a8..5a80d8bdf 100644
--- a/integration-tests/it-exporter/it-exporter-test/src/test/java/io/prometheus/metrics/it/exporter/test/ExporterIT.java
+++ b/integration-tests/it-exporter/it-exporter-test/src/test/java/io/prometheus/metrics/it/exporter/test/ExporterIT.java
@@ -110,11 +110,15 @@ public void testPrometheusProtobufDebugFormat(String format, String expected) th
             .replace("<app>", sampleApp);
 
     if ("prometheus-protobuf".equals(format)) {
-      assertThat(actualResponse)
-          .matches(
-              Pattern.quote(expectedResponse)
-                  .replace("<CREATED_TIMESTAMP_SECONDS>", "\\E\\d+\\Q")
-                  .replace("<CREATED_TIMESTAMP_NANOS>", "\\E\\d+\\Q"));
+      // Protobuf text format omits fields with value 0, so nanos may be absent.
+      // Replace the nanos placeholder with a regex-friendly marker before quoting.
+      String withOptionalNanos =
+          expectedResponse.replace("\n      nanos: <CREATED_TIMESTAMP_NANOS>", "<OPTIONAL_NANOS>");
+      String pattern =
+          Pattern.quote(withOptionalNanos)
+              .replace("<CREATED_TIMESTAMP_SECONDS>", "\\E\\d+\\Q")
+              .replace("<OPTIONAL_NANOS>", "\\E(\n      nanos: \\d+)?\\Q");
+      assertThat(actualResponse).matches(pattern);
     } else {
       assertThat(actualResponse).isEqualTo(expectedResponse);
     }