diff --git a/backend/src/routes/experiments.js b/backend/src/routes/experiments.js
index 3251884..1db58e1 100644
--- a/backend/src/routes/experiments.js
+++ b/backend/src/routes/experiments.js
@@ -1,5 +1,6 @@
 const router = require('express').Router();
 const { body } = require('express-validator');
+const { Prisma } = require('@prisma/client');
 const prisma = require('../lib/prisma');
 const cache = require('../lib/cache');
 const auditMiddleware = require('../middleware/auditMiddleware');
@@ -373,7 +374,7 @@ router.get('/:id/daily-statuses', async (req, res, next) => {
       where.date = { gte: d, lt: next };
     }
     if (analysisOnly) {
-      where.NOT = { analysis_summary: null };
+      where.NOT = { analysis_summary: Prisma.DbNull };
     }
 
     const statuses = await prisma.dailyStatus.findMany({