Aprocitentan: Another Dial for Hard to Control Blood Pressure

Resistant hypertension is a traffic jam of mechanisms: salt, aldosterone, sympathetic drive, stiff vessels. Most drugs push on one lever. Aprocitentan pushes on a different one, the endothelin pathway, and two new analyses from its phase 3 trial, PRECISION, ask how hard that lever moves in the patients who need it most: people with obesity, and people whose heart, kidney and metabolic problems pile up together.

The headline number is 16.0 mmHg. It is real. It is also not the number that tells you what the drug did.

How the trial was built

PRECISION screened 1,965 people and randomized 730 across Europe, North America, Asia and Australia between 2018 and 2022. To get in, patients had to have a sitting systolic pressure of at least 140 mmHg while taking a standardized background of three drugs, including a diuretic. Per the FDA label, that meant an angiotensin receptor blocker, a calcium channel blocker and a diuretic throughout.

The design came in three parts. Part 1 was four weeks, double blind, with two doses of aprocitentan against placebo. Part 2 was 32 weeks in which everyone took the drug and only the patients were blinded. Part 3 was a 12 week withdrawal: patients were randomized again to stay on the drug or switch to placebo. Of the 730 randomized, 577 completed all three parts.

The population was not a gentle one. Mean age was 62, 60 percent were men, and mean body mass index was 34. Per the label, about 54 percent had diabetes, 20 percent congestive heart failure, and 63 percent were taking four or more blood pressure drugs at baseline. The trial was funded by Idorsia and Janssen, and the full results were published in The Lancet in 2022.

The number that matters: the gap with placebo

Here is the part a press release tends to skip. In the overall trial, office systolic pressure fell by 15.3 and 15.2 mmHg at four weeks on the two aprocitentan doses. On placebo, it fell by 11.5 mmHg. Closer follow up, better pill taking and regression to the mean push readings down in any trial. The drug's own effect is the difference: 3.8 and 3.7 mmHg.

That is modest, but not the whole picture. On 24 hour ambulatory monitoring, which is harder to game with a good day at the clinic, the difference versus placebo was 4.2 and 5.9 mmHg. And the withdrawal part is the cleanest test in the design: after four weeks off the drug, office systolic pressure rose by 5.8 mmHg more on placebo than on aprocitentan. Take the drug away and pressure climbs back.

A 16 point drop sounds like a breakthrough. A 4 point gap over placebo, on top of three or four other drugs, is the honest unit, and in this population even that is worth having.

What the new obesity and CKM analyses add

The new material comes from two post hoc analyses presented at the American Heart Association's Hypertension Scientific Sessions on October 10, 2026, and summarized by Idorsia in a release two days later. Post hoc means the questions were asked after the trial was over, which makes them useful for generating hypotheses and weak for confirming them.

The obesity analysis compared 506 patients with a body mass index of 30 or more against 224 without obesity. In the patients with obesity, office systolic pressure fell by 15.4 and 16.0 mmHg at week 4 on the two doses. Those are changes from baseline, not differences from placebo, and the release does not give the placebo figure for this subgroup. The release calls the result consistent with the overall trial, which most likely implies a placebo adjusted effect of a few mmHg, not sixteen. It also reports that a urine marker of kidney strain, the albumin to creatinine ratio (UACR), decreased, without giving a percentage.

The close to 50 percent UACR figure comes from the second analysis, on the cardiovascular kidney metabolic (CKM) spectrum: 410 patients at CKM stage 2 and 273 at stage 4a. In those with albuminuria, UACR fell by almost half at both stages, and kidney filtration stayed stable. A falling marker is not yet fewer dialysis starts or heart attacks. We have seen that gap before: in our piece on Lp(a) and the HORIZON trial, a big biomarker drop did not become fewer events.

Side effects

The most common problem was edema or fluid retention, mostly mild to moderate. In the four week double blind part it occurred in 9 percent on the lower dose, 18 percent on the higher dose and 2 percent on placebo, and it led seven patients on aprocitentan to stop. Eleven treatment emergent deaths occurred during the trial; investigators judged none to be related to the drug.

The FDA label adds detail. Anemia was reported in 3.7 percent on the approved dose versus none on placebo, and a hemoglobin drop of more than 2 g/dL was seen in 7 percent versus 1 percent. The label carries a boxed warning for embryo fetal toxicity, so the drug is contraindicated in pregnancy, plus warnings for liver injury, fluid retention and decreased sperm counts. It is not recommended in advanced heart failure, where it was not studied. Only the lower of the two trial doses is approved in the US; the label says the higher one did not lower pressure meaningfully more and roughly doubled fluid retention. None of this is a reason to start or stop a medication on your own; that conversation belongs with a doctor.

Limits, in order of size

First, no outcomes. The label is explicit: there are no controlled trials showing that aprocitentan itself reduces strokes, heart attacks or deaths. The bet is that lower pressure helps whatever the drug, which has held across many classes. Second, the comparator was placebo. PRECISION did not test aprocitentan against spironolactone, the add on most clinicians reach for at this stage. Third, the long stretch was not placebo controlled. Reductions held to week 36 in the obesity group, says the release, but in part 2 everyone was on the drug. Fourth, the new numbers are sponsor framed post hoc cuts, available as conference abstracts and a press release rather than a peer reviewed paper. To check how we sort these layers, see how to read a health study in 5 minutes.

What to watch next

Three things would change the reading. A full peer reviewed paper for the obesity and CKM analyses, with placebo adjusted numbers per subgroup. Outcome data, which no trial has reported. And a head to head test against the usual fourth line options. The drug has been sold in the US since October 2024 and is approved in the EU, the UK, Switzerland and Canada, so real world data on fluid retention and anemia should accumulate. The kidney marker story will probably get more attention than the blood pressure story, because a falling UACR is where endothelin blockade looks most like something new rather than one more pill on the pile.