Dapagliflozin (Farxiga/Forxiga), already approved for diabetes and CKD, is being tested in the STOP-PKD Phase 3 trial — the first large-scale SGLT2 inhibitor study designed specifically for ADPKD patients.
Background
SGLT2 inhibitors have revolutionized kidney disease treatment — they're now standard of care for diabetic kidney disease and general CKD. But ADPKD was always excluded from those trials. The University of Cologne is now running STOP-PKD, a dedicated Phase 3 trial to prove dapagliflozin works specifically in polycystic kidneys. This is significant because if it works, the drug is already approved and could be prescribed off-label almost immediately.
How It Works
Dapagliflozin blocks the SGLT2 transporter in the proximal tubule, causing glucose to be excreted in urine. But the kidney benefits go far beyond glucose lowering: SGLT2 inhibitors reduce intraglomerular pressure, decrease tubular workload, reduce inflammation and fibrosis, and activate tubuloglomerular feedback. In ADPKD specifically, they may also reduce cyst fluid secretion through changes in tubular flow and osmolarity.
Clinical Trial Details
STOP-PKD (NCT07280585) is a Phase 3, multicenter, double-blind, placebo-controlled trial of 420 ADPKD patients receiving dapagliflozin 10mg daily for 36 months. Primary endpoint is chronic eGFR slope (rate of kidney function decline). Sites across Germany, Netherlands, Austria, and Spain. Began recruiting December 2025, estimated completion 2029.
Why It's Promising
This is one of the most promising trials in the PKD pipeline. The drug is already approved, well-tolerated, and extensively studied. Positive results could change practice overnight — nephrologists could prescribe it immediately. The 3-year timeline with eGFR slope endpoint is rigorous and regulators know this drug well.
Limitations & Concerns
Results won't be available until 2029 at earliest. SGLT2 inhibitors cause an initial eGFR 'dip' that complicates interpretation. Some smaller studies of SGLT2 inhibitors in ADPKD have shown mixed early signals. The mechanism may slow progression without affecting cyst growth directly.