Idorsia Pharmaceuticals U.S. Inc. announced the US Food and Drug Administration (FDA) approval of Tryvio™ (aprocitentan) for the treatment of hypertension in combination with other antihypertensive drugs, to lower blood pressure in adult patients who are not adequately controlled on other drugs.1 Lowering blood pressure reduces the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarctions.1 The recommended dosage of Tryvio is 12.5 mg orally once daily, with or without food.
Tryvio (aprocitentan) is an endothelin receptor antagonist that inhibits the binding of endothelin (ET)-1 to ETA and ETB receptors.1,2 The effects of ET-1 bear many similarities with the pathophysiology of hypertension,3 and ET-1 is a major driver of aldosterone production.4 Until the approval of Tryvio, no systemic antihypertensive medications targeted the ET pathway,5 as approved antihypertensive therapies focus on the regulation of salt and water (diuretics), antagonism of the renin–angiotensin–aldosterone (RAAS) system, reduction of influx of extracellular calcium into the cell (calcium channel blockers), sympatholytic activity (beta blockers, central alpha-agonist agents), or non-selective vasodilatory effects.6,7
Tryvio was evaluated as a monotherapy in a Phase 2 study in patients with hypertension,8 and as an add-on therapy in a Phase 3 study called PRECISION in patients with confirmed resistant hypertension.9 In PRECISION, aprocitentan was well tolerated and superior to placebo in lowering blood pressure at week 4, with a sustained effect at week 40.10
Following the 4-week placebo run-in period, 730 patients were randomized equally to aprocitentan at either 12.5 mg, 25 mg, or placebo once daily during the initial 4-week double-blind (DB) treatment period (part 1). At the end of 4 weeks, all patients entered the single-blind treatment period (part 2) where they received 25 mg aprocitentan once daily for 32 weeks. At the end of the 32 weeks, patients were re-randomized to receive either 25 mg aprocitentan or placebo, once daily, during a 12-week DB-withdrawal period (part 3).
The primary efficacy endpoint was the change in sitting SBP (SiSBP) from baseline to Week 4 during part 1, measured at trough by unattended automated office blood pressure (uAOBP).
The key secondary endpoint was the change in SiSBP measured at trough by uAOBP from Week 36 (i.e., prior to randomized withdrawal to 25 mg aprocitentan or placebo in part 3) to Week 40.
Patients had a mean age of 62 years (range 24 to 84 years) and 60% were male. Patients were White (83%), African American (11%) or Asian (5%). Approximately 10% were Hispanic. The mean body mass index (BMI) was 34 kg/m2 (range 18 to 64 kg/m2). At baseline, 19% of patients had an eGFR 30–59 mL/min/1.73 m2 and 3% had an eGFR 15–29 mL/min/1.73 m2. At baseline, 24% of patients had a urine albumin-to-creatinine ratio (UACR) of 30–300 mg/g and 13% had a UACR >300 mg/g. Approximately 54% of patients had a medical history of diabetes mellitus, 31% ischemic heart disease, and 20% congestive heart failure. At baseline, 63% of patients reported taking four or more antihypertensive medications.
Tryvio 12.5 mg was statistically superior to placebo in reducing SiSBP at Week 4 (part 1). The treatment effect was consistent for sitting diastolic BP (SiDBP).
The persistence of the BP-lowering effect of Tryvio was demonstrated in part 3 of the trial, in which patients on aprocitentan were re-randomized to placebo or 25 mg aprocitentan following a period during which all patients were treated with 25 mg. In patients re-randomized to placebo, the mean SiSBP increased, whereas in patients re-randomized to 25 mg aprocitentan the mean effect on SiSBP was maintained and was statistically superior to placebo at Week 40. The treatment effect was consistent for SiDBP.
Most of the BP-lowering effect occurred within the first two weeks of treatment with Tryvio. Tryvio is not approved for use at a 25 mg dose. The efficacy for the 25 mg aprocitentan dose as measured in the primary end point of change in sitting SBP (SiSBP) from baseline to Week 4 in part 1, was similar to the 12.5 mg dose and thus aprocitentan 12.5 mg is the approved dose.
Tryvio's BP-lowering effect appeared consistent among subgroups defined by age, sex, race, BMI, baseline eGFR, baseline UACR, medical history of diabetes, and between BP measurement methodologies (uAOBP and ambulatory BP measurements).
The most frequently reported adverse reactions to Tryvio during the 4-week double-blind placebo-controlled treatment period (part 1) of the PRECISION study were edema/fluid retention and anemia. During the initial 4-week double-blind placebo-controlled treatment period (part 1), 0.8% of patients experienced an adverse reaction of hypersensitivity (i.e., rash, erythema, allergic edema) on Tryvio compared to no reports in patients treated with placebo. One patient experienced allergic dermatitis requiring hospitalization while receiving aprocitentan 25 mg. Tryvio is contraindicated in patients who are hypersensitive to aprocitentan or any of its excipients. Use of Tryvio is contraindicated in pregnancy.
Lowering BP reduces the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes. There are no controlled trials demonstrating reduction of risk of these events with Tryvio.
The team at Idorsia has been working on the research and development of endothelin receptor antagonists for more than 30 years, successfully bringing three other molecules from this class to patients in different indications. ET-1, via its receptors (ETA and ETB), mediates a variety of deleterious effects such as vasoconstriction, fibrosis, cell proliferation, and inflammation. In hypertension, ET-1 can cause endothelial dysfunction, vascular hypertrophy and remodeling, sympathetic activation, and increased aldosterone synthesis.1
