Ditekiren

Summary

Ditekiren (also known as Ro 42‑5892) is a synthetic pseudo‑hexapeptide that acts as a potent inhibitor of renin, the enzyme that initiates the renin‑angiotensin system. Developed as a research‑stage antihypertensive agent, it has been evaluated in animal models and in early human studies, but it has not received regulatory approval for clinical use.

Mechanism of Action

Ditekiren mimics the transition state of angiotensinogen cleavage and binds tightly to the active site of renin, blocking conversion of angiotensinogen to angiotensin I. This reduces plasma renin activity and downstream angiotensin II formation, lowering vasoconstriction and aldosterone release. In vitro studies also show that the peptide can inhibit the ATP‑binding cassette transporter SPGP, suggesting additional effects on cellular drug transport.

What the Research Shows

Preclinical work in rats showed that ditekiren is cleared rapidly by the liver, with nonlinear uptake and biliary excretion that become saturated at higher doses. In a rat model infused with human renin, oral ditekiren produced dose‑dependent hypotension that was more pronounced than with hog renin, reflecting higher affinity for human renin. Early human trials reported dose‑dependent reductions in plasma renin activity, though blood‑pressure responses were variable and sometimes dissociated from PRA changes. Formulation studies demonstrated good compatibility with human and monkey plasma, no platelet aggregation, and no red‑cell lysis. However, intravenous infusion in cynomolgus monkeys revealed a risk of intravascular precipitation unless infusion rates and concentrations were carefully controlled.

Reported Benefits

Animal studies indicate that ditekiren can produce sustained hypotensive effects without tachyphylaxis, and early human data suggest it lowers plasma renin activity, a key driver of hypertension. Its high specificity for renin may avoid some off‑target effects seen with ACE inhibitors, such as bradykinin‑mediated cough. In vitro tests show the drug is compatible with blood components, supporting intravenous administration.

Limitations of the Evidence

Evidence is limited to small early‑phase human studies and animal models; the relationship between PRA reduction and blood‑pressure lowering is inconsistent. Oral bioavailability is unclear, and hepatic clearance appears nonlinear, potentially complicating dosing. The peptide is prone to precipitation at physiological pH and temperature, posing formulation challenges for IV use. No regulatory approval exists, and larger clinical trials are lacking.

Safety Considerations

Limited clinical data describe ditekiren as generally well tolerated, with no major adverse events reported. In vitro, the drug does not cause platelet aggregation, protein flocculation, or red‑cell lysis at concentrations far above expected clinical levels. Nevertheless, intravenous infusion can lead to intravascular precipitation, especially if the solution is too concentrated or infused too quickly, as observed in monkey studies. Hepatic elimination is rapid and nonlinear, suggesting potential for accumulation at high doses.

How It Is Administered

Ditekiren has been studied for intravenous and subcutaneous delivery. Intravenous formulations use acidified dextrose (pH ≈ 4) to maintain solubility; careful control of concentration and infusion rate is required to avoid precipitation. Subcutaneous administration has been explored in animal studies but detailed formulation data are not available.

Routes of Administration

Goals & Uses

• Blood pressure reductionCardiovascularModerate
• Renin inhibition (pharmacological probe)ResearchHigh
• RAAS characterizationResearchHigh

Contraindications

• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• Concurrent use with ACE inhibitors or ARBs in diabetic patientsDrug InteractionModerate
• Known hypersensitivity to ditekiren or excipientsAllergyHigh

Adverse Effects

• Injection site reactionsLocalCommon
• HypotensionCardiovascularUncommonLow blood pressure
• Renal function impairmentRenalRare
• HyperkalemiaElectrolyte ImbalanceUncommon

Drug Interactions

• Angiotensin Receptor Blockers (ARBs)Moderate
• ACE inhibitorsModerate
• Potassium-sparing diureticsModerate

Population Constraints

• Pediatric patientsAgeRelative
• Patients with severe renal artery stenosisRenalAbsolute
• Pregnant womenReproductiveAbsolute
• Volume-depleted patientsCardiovascularRelative

Regulatory Status

• European UnionUnapprovedNever received EMA review; research compound only.
• United StatesUnapprovedNever submitted to FDA; research compound only.
• United KingdomUnapprovedNo MHRA submission; remains a research tool compound.

Ditekiren was never submitted for regulatory approval in any jurisdiction. It remains a research compound used primarily to characterize renin inhibitor pharmacology.

Evidence & Sources

• Hepatic elimination in the rat of ditekiren (U-71038), a renin inhibitor pseudohexapeptide
  Journal ArticleLowAdedoyin A, Perry PR, Wilkinson GR1993-01-01T00:00:00.000000Z
• Renin inhibitors in hypertension
  Journal ArticleModerateLuther RR, Glassman HN, Boger RS1991-01-01T00:00:00.000000Z
• Rat model for evaluating inhibitors of human renin
  Journal ArticleLowPals DT, Lawson JA, Couch SJ1990-01-01T00:00:00.000000Z
• In vitro evaluation of the plasma and blood compatibility of a parenteral formulation for ditekiren, a novel renin inhibitor pseudopeptide
  Journal ArticleLowGreenfield JC, et al.1991-01-01T00:00:00.000000Z
• Cloning and expression of murine sister of P-glycoprotein reveals a more discriminating transporter than MDR1/P-glycoprotein
  Journal ArticleLowLecureur V, et al.2000-01-01T00:00:00.000000Z
• Precipitation of the renin inhibitor ditekiren upon i.v. infusion; in vitro studies and their relationship to in vivo precipitation in the cynomolgus monkey
  Journal ArticleLowDavio SR, et al.1991-01-01T00:00:00.000000Z

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