Updated May 2026 · ClinicalTrials.gov

RECRUITINGPhase 2INTERVENTIONAL

Recombinant Human C1 Esterase Inhibitor (Conestat Alfa) in the Prevention of Acute Ischemic Cerebral and Renal Events After Transcatheter Aortic Valve Implantation

Q: What is the NCT05145283 clinical trial studying?

The aim of this trial is to assess the safety and efficacy of conestat alfa (Ruconest®, Pharming Technologies B.V.) on renal and cerebral ischemic events in patients undergoing TAVI for severe symptomatic aortic stenosis (AS) compared to placebo. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Q: Who can participate in NCT05145283?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

Q: How do I contact the trial site for NCT05145283?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Q: Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Q: Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

Recombinant Human C1 Esterase Inhibitor (Conestat Alfa) in the Prevention of Acute Ischemic Cerebral and Renal Events After Transcatheter Aortic Valve Implantation: a Multi-center, Randomized, Double-blind, Placebo-controlled Investigational Study (PAIR-TAVI).

Recombinant Human C1 Esterase Inhibitor (Conestat Alfa) in the Prevention of Acute Ischemic Cerebral and Renal Events After Transcatheter Aortic Valve Implantation (NCT05145283) is a Phase 2 interventional studying Acute Ischemic Stroke and Acute Renal Injury, sponsored by University Hospital, Basel, Switzerland. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Acute Ischemic Stroke and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 250 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Acute Ischemic Stroke subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: - willing to sign a consent form as documented by signature - Severe AS and scheduled for transfemoral TAVI Who Should NOT Join This Trial: - Contraindications to the class of drugs under study (C1INH), e.g., known hypersensitivity or allergy to class of drugs or the investigational product - History of allergy to rabbits (as rhC1INH is derived from the breast milk of transgenic rabbits) - Women who are pregnant or breast feeding - Hemodynamic instability requiring emergency TAVI - Valve-in-valve procedure - Other access route than transfemoral - Non-cardiac co-morbidity with expected survival \<6 months - Ischemic or hemorrhagic stroke within 30 days before TAVI - Dialysis or estimated glomerular filtration rate (eGFR) \<20 ml/min/1.73m2 - Contraindication for MRI such as a permanent non-MRI compatible pacemaker or severe claustrophobia - Liver cirrhosis (any Child-Pugh score) - Incapacity or inability to provide willing to sign a consent form - Participation in another study with investigational drug or medical device within the 30 days preceding and during the present study - Previous enrolment into the current study - Any uncontrolled or significant concurrent illness that would put the patient at a greater risk or limit compliance with the study requirements at the discretion of the investigator Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: * Informed consent as documented by signature * Severe AS and scheduled for transfemoral TAVI Exclusion Criteria: * Contraindications to the class of drugs under study (C1INH), e.g., known hypersensitivity or allergy to class of drugs or the investigational product * History of allergy to rabbits (as rhC1INH is derived from the breast milk of transgenic rabbits) * Women who are pregnant or breast feeding * Hemodynamic instability requiring emergency TAVI * Valve-in-valve procedure * Other access route than transfemoral * Non-cardiac co-morbidity with expected survival \<6 months * Ischemic or hemorrhagic stroke within 30 days before TAVI * Dialysis or estimated glomerular filtration rate (eGFR) \<20 ml/min/1.73m2 * Contraindication for MRI such as a permanent non-MRI compatible pacemaker or severe claustrophobia * Liver cirrhosis (any Child-Pugh score) * Incapacity or inability to provide informed consent * Participation in another study with investigational drug or medical device within the 30 days preceding and during the present study * Previous enrolment into the current study * Any uncontrolled or significant concurrent illness that would put the patient at a greater risk or limit compliance with the study requirements at the discretion of the investigator

Treatments Being Tested

DRUG

Conestat alfa (Ruconest®)

In the current study, participants will receive two intravenous injections of conestat alfa (immediately during the TAVI procedure and again 3h later) at a dose of 100 U/kg (first dose) and of 50 U/kg (subsequent dose), for patients less than 84 kg; two intravenous injections (immediately during the TAVI procedure and again 4h later) of conestat at a dose of 8400 U (4 vials, first dose) and of 4200 U (2 vials, subsequent dose) for patients of 84 kg body weight or greater. The chosen regimen including repeated administration should increase and maintain serum C1INH levels above twice the serum concentration for six to eight hours in the majority of patients. The timeframe of therapeutic concentrations will cover the period of the TAVI procedure itself and the immediate postprocedural period during which reperfusion and additional ischemic events related to global hypoperfusion may occur.

DRUG

NaCl 0.9%)

Normal saline (NaCl 0.9%) will serve as placebo treatment. The respective amount of saline (according to patient weight matching the volume of conestat alfa that would have been used for this patient) will be withdrawn in an opaque syringe for slow IV injection.

Locations (2)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

University Hospital Basel, Division of Internal Medicine

Basel, Switzerland

Stadtspital Triemli Zürich, Division of Cardiology

Zurich, Switzerland

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT05145283), the sponsor (University Hospital, Basel, Switzerland), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT05145283 clinical trial studying?

The aim of this trial is to assess the safety and efficacy of conestat alfa (Ruconest®, Pharming Technologies B.V.) on renal and cerebral ischemic events in patients undergoing TAVI for severe symptomatic aortic stenosis (AS) compared to placebo. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT05145283?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT05145283?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT05145283. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05145283. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.