Observational Study With CICR-NAM as a Food for Special Medicinal Purposes in Post-COVID Syndrome (PCS) (CICR-NAM-PCS)

August 27, 2026 updated by: University Hospital Schleswig-Holstein

In patients with post-COVID syndrome, changes in tryptophan metabolism, energy metabolism, and the gut microbiome may occur. In an earlier nutritional study, patients with COVID-19 recovered their physical performance more quickly when taking nicotinamide (vitamin B3). Patients who responded to nicotinamide also developed post-COVID syndrome less frequently. At the University Hospital Schleswig-Holstein in Kiel, special nicotinamide tablets (CICR-NAM) were developed that release the active substance selectively in the lower intestine and have been shown to be very well tolerated in several studies.

Patients with post-COVID syndrome and documented tryptophan deficiency may therefore take one tablet (500 mg) of CICR-NAM daily for up to approximately 4 months as a food for special medicinal purposes within the therapy groups of the outpatient clinic for patients with post-COVID syndrome at the University Hospital Schleswig-Holstein in Kiel. This intake is far below the Upper Level defined by the European Food Safety Authority for lifelong daily intake (900 mg per day). Therefore, there are no safety concerns. CICR-NAM intake is intended to complement the therapy group programme by supporting energy metabolism.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

In the COVit-2 study (DRKS00021214), daily intake of two tablets containing a total of 1,000 mg nicotinamide (500 mg conventional nicotinamide and 500 mg controlled-ileocolonic-release nicotinamide, CICR-NAM) in patients with acute COVID-19 was associated with a significantly faster improvement in physical performance after two weeks compared with placebo. Parallel effects on the gut metagenome suggested that specifically the ileocolonically released nicotinamide from CICR-NAM tablets could counteract COVID-19-associated disturbances in the metabolism of the essential amino acid tryptophan and in the gut microbiome. In the placebo group, gene expression related to the microbial tryptophan biosynthesis pathway as well as redox and salvage pathways of the central metabolic coenzyme nicotinamide adenine dinucleotide (NAD+) was significantly increased at week 2, whereas these deviations in the metagenome were not observed in patients receiving nicotinamide supplementation.

At the 6-month follow-up of COVit-2 participants, patients who benefited from nicotinamide administration (responders) developed post-COVID syndrome significantly less frequently. Because disturbances in tryptophan metabolism are well described in both COVID-19 and PCS, a low tryptophan level may serve as an easily measurable surrogate parameter for an increased nicotinamide requirement in these conditions.

There is currently no satisfactory treatment for patients with PCS. They experience significant distress and often have a permanent disability. Given the disturbances in tryptophan metabolism and the gut microbiome observed in PCS, supplementation with CICR-NAM may help restore physical performance. Therefore, a nutritional observational study offering 500 mg/day CICR-NAM as a food for special medicinal purposes for up to approximately 4 months will be conducted within the therapy groups of the PCS outpatient clinic at UKSH Campus Kiel for patients with documented tryptophan deficiency. A placebo-controlled clinical trial with CICR-NAM in PCS is planned, but it will not be available for recruitment in the near future. The present observational study is intended as an interim option until the clinical trial begins and is also expected to provide insights into the feasibility of such an intervention.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • all sexes;
  • minimum age 18 years; no upper age limit;
  • post-COVID syndrome (PCS)
  • serum tryptophan <55 µmol/L (UKSH reference range: 48-109 µmol/L);
  • participation in the therapy groups of the PCS outpatient clinic at UKSH Campus Kiel.

Exclusion Criteria:

  • Known allergies or intolerances to any component of CICR-NAM;
  • inability to provide informed consent;
  • pregnancy or breastfeeding;
  • severe comorbid disease (especially renal insufficiency, uncontrolled autoimmune diseases, liver disease, or malignancy);
  • long-term use of higher doses of medications that raise gastric pH (for example proton pump inhibitors, H2 receptor antagonists, or antacids), as an increase in pH toward approximately 7 may cause premature release of nicotinamide from CICR-NAM;
  • use of supplements containing more than 20 mg nicotinamide, nicotinamide riboside, nicotinamide mononucleotide, nicotinic acid, or NAD+ per daily dose.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Supportive Care
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: CICR-NAM Administration
Oral administration of CICR-NAM (controlled-ileocolonic-release nicotinamide) as a food for special medical purposes, one film-coated tablet (500 mg) daily for up to approximately 4 months, embedded in the therapy groups of the PCS outpatient clinic at UKSH Campus Kiel.
Dietary supplement: CICR-NAM
Oral administration of CICR-NAM (controlled-ileocolonic-release nicotinamide) as a food for special medical purposes, one film-coated tablet (500 mg) daily for up to approximately 4 months, embedded in the therapy groups of the PCS outpatient clinic at UKSH Campus Kiel

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Serum tryptophan level
Time Frame: From T1 (start of participation, screening for reduced serum tryptophan) to T6 (end of the therapy group) approximately 5 month.
Serum tryptophan level (µmol/L) as a longitudinal marker of tryptophan and NAD+ metabolism during CICR-NAM supplementation. Assessment time points: therapy group session 1 (start of participation, screening for reduced serum tryptophan, T1), session 2 (start of supplementation, T2), session 3 (after approximately 1 month of supplementation, T3), and session 6 (end of the therapy group, after approximately 4 months, T4). Method: quantitative determination of serum tryptophan (UKSH laboratory diagnostics)
From T1 (start of participation, screening for reduced serum tryptophan) to T6 (end of the therapy group) approximately 5 month.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Hospital Schleswig-Holstein

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 6, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 30, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 30, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 6, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 27, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 1, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 1, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CICR-NAM-PCS_V01_2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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