The gold-standard test said lanreotide did nothing for kidney function in polycystic kidney disease. A cheaper estimate said it helped. The gap between those two answers is the whole story, and the researchers who ran the trial come down on the side of the one that said nothing.
Lanreotide is a peptide, a lab-made copy of the hormone somatostatin sold as Somatuline and mostly used for acromegaly and neuroendocrine tumors. For more than a decade it has been tested off-label against autosomal dominant polycystic kidney disease (ADPKD), the most common inherited kidney disease, in which fluid-filled cysts slowly grow and crowd out working tissue until about half of patients reach kidney failure by their late fifties. Somatostatin drugs slow the fluid secretion that inflates those cysts, and earlier studies showed they can shrink total kidney and liver volume. The open question was whether smaller cysts translate into kidneys that keep filtering.
The answer, from the last randomized trial the class is likely to get, is no. The Lanreotide In Polycystic kidney disease Study (LIPS), published in Kidney International ↗ by Dominique Joly and colleagues in Paris, gave adults with ADPKD and moderate kidney impairment either lanreotide 120 mg by monthly injection or a saline placebo for three years. Slow recruitment stopped the trial at 144 of a planned 180 patients.
The primary endpoint was the one nephrologists trust most: measured filtration rate, tracked by how fast the kidneys clear an injected marker called iohexol. On that yardstick, the two groups declined at essentially the same pace. The difference between arms was 0.3 ml/min/1.73 m2 per year in favor of placebo, with a confidence interval running from -3.4 to 2.8, an interval so wide and so centered on zero that it rules out any meaningful benefit. The trial missed.
Then came the number that muddies things. When the same decline was estimated the cheap way, from blood creatinine rather than an injected marker, lanreotide looked like it slowed the drop by about 1.2 ml/min/1.73 m2 per year (95 percent confidence interval 0.27 to 2.15, nominal p = 0.012). Read on its own, that is the kind of result that keeps a drug alive.
It should not be read on its own. Creatinine is a byproduct of muscle that the kidney both filters and, to a degree, secretes, and somatostatin drugs can nudge how much of it the body makes and handles. That opens a path for the estimate to move even when true filtration does not. The trial had two ways to check, and both came up short: an alternative estimate based on cystatin C, a marker that does not lean on creatinine, and a direct timed urine collection. Neither confirmed the creatinine signal. When the trustworthy measure is flat and only the flawed proxy moves, the proxy is usually being fooled.
That is how an accompanying commentary ↗ by Ron Gansevoort and Thomas Bais reads it. They call LIPS the last randomized evaluation of somatostatin analogues in ADPKD and conclude it backs the current Kidney Disease: Improving Global Outcomes guidance not to prescribe these drugs solely to protect kidney function. The record across the class points the same way. The larger DIPAK-1 trial ↗ in JAMA in 2018 also failed to show lanreotide slowing kidney decline, and octreotide, the other somatostatin analogue tested in ADPKD, never cleared the bar either. Tolvaptan, a vasopressin blocker and not a peptide, remains the only drug approved to slow the disease.
Lanreotide lives on peptidemodel as a card built against SSTR2 ↗, the somatostatin receptor it activates, where its documented uses are the tumor and hormone indications the LIPS result leaves untouched. What the trial closes is narrower and worth stating plainly: shrinking cysts is not the same as preserving filtration, and an estimate that flatters a drug is not evidence until the measure that counts agrees.