Introduction: Renin-angiotensin system (RAS) inhibitors decrease urinary albumin:creatinine ratio (UACR) and are guideline recommended drugs for kidney protection but are ineffective in lowering UACR in up to 40% of cases. We hypothesized that rotation to another drug class overcomes resistance to RAS inhibition and tested this hypothesis in a randomized cross-over trial. Methods: We assigned 26 adults with type 1 diabetes and 37 with type 2 diabetes and UACR ≥30 and ≤500 mg/g to 4-week treatment periods with telmisartan 80 mg, empagliflozin mg, linagliptin 5 mg, and baricitinib 2 mg in random order, separated by 4-week wash-out periods. Participants were then re-exposed for 4-weeks to the individual drug that induced the largest UACR reduction. Primary outcome was the difference in UACR response between the first and second exposure to the best performing drug, versus the difference in UACR response between the best performing drug and the other three drugs. Results: There was substantial between person variation in the best performing drug: telmisartan was best performing in 33 (52%) participants, followed by empagliflozin and linagliptin in (17%) participants each, and baricitinib in 8 (13%) participants. The individual best performing drug changed UACR during the first exposure by -39.6% (95%CI -44.8, -33.8, p<0.001) and by -22.4% (95%CI -29.7, -12.5, p<0.001) at re-exposure (between exposure difference: 22.1% [95%CI 12.5, 30.8; p<0.001]) . The difference in UACR response between the individual best performing drug and the other three drugs was -40.5% (95%CI -45.9, -34.6, p<0.0vs. between exposure difference) . The correlation in UACR response of the best performing drug at exposure and re-exposure was r=0.389, p=0.017. Conclusion: We demonstrated a large and reproducible variation in UACR lowering responses to different drug classes reinforcing the need for personalized therapy approaches to overcome therapy resistance to guideline recommended treatment. Disclosure V.Rotbain curovic: None. P.Rossing: Consultant; Astellas Pharma Inc., AstraZeneca, Bayer AG, Gilead Sciences, Inc., Merck Sharp & Dohme Corp., Novo Nordisk A/S, Sanofi, Speaker's Bureau; Eli Lilly and Company. H.L.Heerspink: Consultant; AstraZeneca, Bayer AG, Boehringer Ingelheim International GmbH, Chinook Therapeutics Inc., CSL Behring, Gilead Sciences, Inc., Goldfinch Bio, Inc., Janssen Research & Development, LLC, Mitsubishi Tanabe Pharma Corporation, Mundipharma, Traveere Pharmaceuticals, Research Support; AstraZeneca, Boehringer Ingelheim International GmbH, Novo Nordisk A/S. M.Y.A.Kroonen: None. N.Jongs: None. T.Sen: None. E.Zobel: Employee; Novo Nordisk. T.W.Hansen: Stock/Shareholder; Novo Nordisk A/S. G.D.Laverman: Advisory Panel; Astellas Pharma Inc., AstraZeneca, Boehringer Ingelheim International GmbH, Lilly Diabetes, Vifor Pharma Management Ltd., Research Support; AstraZeneca, Lilly Diabetes, Sanofi, Vifor Pharma Management Ltd. A.Kooy: Advisory Panel; Bayer AG, Research Support; Boehringer Ingelheim International GmbH, Novo Nordisk, Speaker's Bureau; Boehringer Ingelheim International GmbH, Eli Lilly and Company, Merck Sharp & Dohme Corp., Mundipharma, Novo Nordisk. F.Persson: Advisory Panel; Amgen Inc., AstraZeneca, Boehringer Ingelheim International GmbH, Novo Nordisk A/S, Research Support; Boehringer Ingelheim International GmbH, Novo Nordisk A/S, Speaker's Bureau; AstraZeneca, Boehringer Ingelheim International GmbH, Novo Nordisk A/S, Sanofi.

Background: The SGLT2 inhibitor dapagliflozin reduces kidney function decline and urine albumin:creatinine ratio (UACR) on a population level. However, there is marked heterogeneity in the efficacy among individual patients. We conducted a decentralized (i.e. at home) N=1 trial to assess the effect of dapagliflozin in individual patients and the feasibility of remote data collection. Methods: Twenty patients with type 2 diabetes, UACR >20 mg/g and eGFR >30 mL/min/1.73m2 entered the randomized placebo-controlled double-blind N=1 trial. Patients were randomly assigned to two periods of 1-week treatment with dapagliflozin 10 mg/day and two periods of 1-week treatment with placebo in random order with 1-week wash-out periods in between. Patients collected and sent their own data with automatic uploading to an online platform and sent early morning urines 5 times/week to the laboratory for albumin and creatinine assessment. Primary outcome was UACR change from baseline (mixed effects model). The study had 80% power to detect a correlation in UACR change between first and second dapagliflozin period of 0.6. Results: Patients had a mean eGFR of 70.2 mL/min/1.73m2 and median UACR of 94.7 mg/g. During the study, dapagliflozin compared to placebo reduced albuminuria by 15.1% (95%CI 3.3 - 28.2; p=0.013). There was a marked variation in the change from baseline in UACR during dapagliflozin treatment periods (range first and second exposure -26.9 to -4.7% and -30.5 to -5.8%, respectively). The individual change in UACR during the first and second exposure correlated in the dapagliflozin periods (r=0.50; p=0.026) but not in the placebo periods (r=0.09; p=0.69). Of all scheduled urine collections (N=816), only 5 collections (0.61%) were not delivered in the laboratory. Conclusion: The individual UACR response to dapagliflozin varies among individual patients and is consistent upon re-exposure. Remote data collection was very reliable with nearly any missed urine collection. Disclosure J.Beernink: None. G.D.Laverman: Advisory Panel; AstraZeneca, Vifor Pharma Management Ltd., Boehringer Ingelheim Inc., Astellas Pharma Inc., Lilly, Other Relationship; Sanofi, AstraZeneca. H.L.Heerspink: Consultant; AstraZeneca, Boehringer Ingelheim International GmbH, Bayer Inc., Eli Lilly and Company, Chinook Therapeutics Inc., CSL Behring, Gilead Sciences, Inc., George Clinical, Merck & Co., Inc., Janssen Research & Development, LLC, Traveere Pharmaceuticals, Novo Nordisk. N.Jongs: Speaker's Bureau; AstraZeneca.