ObesityNCT05170867
The Impact of Hafnia Alvei on Weight Loss and Glycaemic Control After Bariatric Surgery
A study testing Hafnia alvei HA4597™ in people with Obesity and Type 2 Diabetes, run by Universidade Nova de Lisboa at 1 site in Portugal.
Trial summary
This study aims to investigate the effects of Hafnia alvei HA4597 TM supplementation on weight loss and glycemic control after bariatric surgery. Patients undergoing Roux-en-Y gastric bypass will receive probiotics or placebo, twice a day, for 90 days, one month after surgery. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Obesity, Type 2 Diabetes
- What is being tested?
- Hafnia alvei HA4597™
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 49 participants
- Where
- 1 sitePortugal
- Study dates
- 14 Jan 2022to 31 Dec 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Men and women between 18 and 65 years
- BMI ≥35 kg/m2 and at least one severe obesity-related complications, or BMI ≥40 kg/m2
- Undergoing Roux-en-Y gastric bypass
- Willing to take a probiotic/placebo supplement twice a day for 60 days
- Willing and able to provide written informed
Who cannot join
- Intake of antibiotics and/or probiotics in the previous 12 weeks
- Weight change >5% in the previous 12 weeks
- Diagnosis of gastrointestinal disease or other significant illness
- Pregnancy or breastfeeding
Trial locations and contacts
1 site in 1 country.
Portugal1 site
NOVA Medical School|Faculdade de Ciências Médicas, Universidade NOVA de Lisboa
Lisbon, 1169-056
About this study
Official title: The Impact of Hafnia Alvei on Weight Loss and Glycaemic Control After Bariatric Surgery - A Randomized, Triple-blind, Controlled Trial
This study aims to investigate the effects of Hafnia alvei HA4597 TM supplementation on weight loss and glycemic control after bariatric surgery. Patients undergoing Roux-en-Y gastric bypass will receive probiotics or placebo, twice a day, for 90 days, one month after surgery. Outcomes will be measured at baseline, and 3, 6, 9 and 12 months after the surgery.
Read the detailed description
Gut microbiota dysbiosis is associated with the pathophysiology of obesity. Bariatric surgery is an effective treatment for obesity that induces changes in the gut microbiota. However, recent studies indicate that the gut microbiota is not fully restored after bariatric surgery which may limit the potential of the surgery to achieve metabolic control and maintain weight loss. Thus, modulating the gut microbiota with probiotics after bariatric surgery could be an effective strategy to improve the success of the surgery.
This study aims to investigate the effects of Hafnia alvei HA4597 TM supplementation on weight loss and glycemic control after bariatric surgery. Patients undergoing Roux-en-Y gastric bypass will receive probiotics or placebo, twice a day, for 90 days, one month after surgery. Outcomes will be measured at baseline, and 3, 6, 9 and 12 months after the surgery.
- Conditions
- Obesity, Type 2 Diabetes
- Being tested
- Hafnia alvei HA4597™, Placebo
- Keywords
- Obesity, Gut microbiota, Probiotics
- Medical subject headings
- Obesity, Diabetes Mellitus, Type 2
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Hafnia alvei HA4597™Dietary supplement
One capsule of probiotic supplement, twice a day, to be taken with water, during each breakfast and lunch (approx. 5 minutes after starting eating), for 90 days. Two capsules of the dietary supplement contain 5x107 CFU of Hafnia alvei HA4597™, 5 mg of zinc and 20 μg of chromium.
PlaceboOther
One capsule of placebo, twice a day, to be taken with water, during each breakfast and lunch (approx. 5 minutes after starting eating), for 90 days. Two capsules of the placebo contain 5 mg of zinc and 20 μg of chromium.
| Study group | Role | What they receive |
|---|---|---|
| Probiotic group | Experimental | Two capsules of Hafnia alvei HA4597™ probiotic/day (5 x 107 CFU/day) for 90 days Receives: Dietary Supplement: Hafnia alvei HA4597™ |
| Placebo group | Placebo comparator | Two identical capsules of placebo/day for 90 days Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Excess weight loss
Changes in percentage of excess weight loss from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
HbA1c
Changes in HbA1c levels (%) from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Secondary outcomes (14)
Gut microbiota
Changes in gut microbiota from baseline. Bacterial DNA will be extracted from faecal samples. 16S rRNA gene will be sequenced by next-generation sequencing (NGS). All the identified bacterial phyla, genus and species will be expressed in percentage.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Gastrointestinal quality of life
Changes in gastrointestinal quality of life by the Gastrointestinal Quality of Life Index (GIQLI) questionnaire from baseline. The GIQLI is a 36 -item questionnaire and consists of 5 different subscales. The total score is calculated as the sum of the 36 items each ranged from 0 to 4. The final score range from 0 to 144 points (lower scores indicate more unfavorable conditions).
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Caseinolytic protease B
Changes in caseinolytic protease B (pM) from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Gut microbiota metabolites
Changes in short-chain fatty acids (acetate, propionate and butyrate) concentrations (mg/mL) from baseline. Short-chain fatty acids will be measured by targeted metabolomics.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Fasting blood glucose
Changes in fasting blood glucose levels (mg/dL) levels from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Insulin
Changes in insulin levels (μU/mL) levels from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
C-peptide
Changes in c-peptide levels (ng/mL) levels from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Total cholesterol
Changes in total cholesterol levels (mg/dL) from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
HDL cholesterol
Changes in high-density lipoprotein (HDL) cholesterol (mg/dL) levels from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
LDL cholesterol
Changes in low-density lipoprotein (LDL) cholesterol (mg/dL) levels from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Triacylglycerides
Changes in triacylglycerides (mg/dL) levels from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Body fat mass
Changes in percentage of body fat mass from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Free fat mass
Changes in free fat mass (kg) from baseline.
Measured: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Proportion of subjects losing more than 50% of baseline excess weight
Percentage of subjects losing >50% of baseline excess weight from baseline to visit 5 (12 months after bariatric surgery).
Measured: At visit 1 (Baseline), visit 5 (12 months after bariatric surgery).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Dec 2021
- Study start14 Jan 2022
- Primary completion31 May 2025
- Study completion31 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 49 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universidade Nova de Lisboa
- Sponsor type
- University, hospital or other
- Collaborators
- Academia CUF
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05170867
- Sponsor's protocol ID
- RESTART
- Status last verified
- May 2026
- First submitted
- 10 Dec 2021
- Last updated
- 8 May 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Ismael S, Vaz C, Durao C, Silvestre MP, Calhau C, Teixeira D, Marques C. The impact of Hafnia alvei HA4597 on weight loss and glycaemic control after bariatric surgery - study protocol for a triple-blinded, blocked randomized, 12-month, parallel-group, placebo-controlled clinical trial. Trials. 2023 May 29;24(1):362. doi: 10.1186/s13063-023-07383-0.
PubMed 37248499
Study at a glance
From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Hafnia Alvei on Weight Loss and Glycaemic Control After Bariatric Surgery - A Randomized, Triple-blind, Controlled Trial
- ClinicalTrials.gov ID
- NCT05170867
- Acronym / sponsor ID
- RESTART
- Conditions
- Obesity, Type 2 Diabetes
- Keywords
- Obesity, Gut microbiota, Probiotics
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 49 participants (actual)
- Lead sponsor
- Universidade Nova de LisboaUniversity, hospital or other
- Collaborators
- Academia CUF
- Study start
- 14 Jan 2022 (actual)
- Primary completion
- 31 May 2025 (actual)
- Study completion
- 31 Dec 2025 (actual)
- First posted
- 28 Dec 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to investigate the effects of Hafnia alvei HA4597 TM supplementation on weight loss and glycemic control after bariatric surgery. Patients undergoing Roux-en-Y gastric bypass will receive probiotics or placebo, twice a day, for 90 days, one month after surgery. Outcomes will be measured at baseline, and 3, 6, 9 and 12 months after the surgery.
Detailed description
Gut microbiota dysbiosis is associated with the pathophysiology of obesity. Bariatric surgery is an effective treatment for obesity that induces changes in the gut microbiota. However, recent studies indicate that the gut microbiota is not fully restored after bariatric surgery which may limit the potential of the surgery to achieve metabolic control and maintain weight loss. Thus, modulating the gut microbiota with probiotics after bariatric surgery could be an effective strategy to improve the success of the surgery.
This study aims to investigate the effects of Hafnia alvei HA4597 TM supplementation on weight loss and glycemic control after bariatric surgery. Patients undergoing Roux-en-Y gastric bypass will receive probiotics or placebo, twice a day, for 90 days, one month after surgery. Outcomes will be measured at baseline, and 3, 6, 9 and 12 months after the surgery.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Probiotic group | Experimental | Dietary Supplement: Hafnia alvei HA4597™Two capsules of Hafnia alvei HA4597™ probiotic/day (5 x 107 CFU/day) for 90 days |
| Placebo group | Placebo comparator | Other: PlaceboTwo identical capsules of placebo/day for 90 days |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Men and women between 18 and 65 years
- BMI ≥35 kg/m2 and at least one severe obesity-related complications, or BMI ≥40 kg/m2
- Undergoing Roux-en-Y gastric bypass
- Willing to take a probiotic/placebo supplement twice a day for 60 days
- Willing and able to provide written informed
Key exclusion criteria (4 listed)
- Intake of antibiotics and/or probiotics in the previous 12 weeks
- Weight change >5% in the previous 12 weeks
- Diagnosis of gastrointestinal disease or other significant illness
- Pregnancy or breastfeeding
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Hafnia alvei HA4597™One capsule of probiotic supplement, twice a day, to be taken with water, during each breakfast and lunch (approx. 5 minutes after starting eating), for 90 days. Two capsules of the dietary supplement contain 5x107 CFU of Hafnia alvei HA4597™, 5 mg of zinc and 20 μg of chromium. | Dietary supplement | Probiotic group |
| PlaceboOne capsule of placebo, twice a day, to be taken with water, during each breakfast and lunch (approx. 5 minutes after starting eating), for 90 days. Two capsules of the placebo contain 5 mg of zinc and 20 μg of chromium. | Other | Placebo group |
Primary outcome
Excess weight loss
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Changes in percentage of excess weight loss from baseline.
HbA1c
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Changes in HbA1c levels (%) from baseline.
14 secondary outcomes
Gut microbiota
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Gastrointestinal quality of life
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Caseinolytic protease B
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Gut microbiota metabolites
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Fasting blood glucose
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Insulin
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
C-peptide
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Total cholesterol
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
HDL cholesterol
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
LDL cholesterol
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Triacylglycerides
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Body fat mass
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Free fat mass
Time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).
Proportion of subjects losing more than 50% of baseline excess weight
Time frame: At visit 1 (Baseline), visit 5 (12 months after bariatric surgery).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 May 2026.
- Derived from this study: PubMed 37248499Ismael S, Vaz C, Durao C, Silvestre MP, Calhau C, Teixeira D, Marques C. The impact of Hafnia alvei HA4597 on weight loss and glycaemic control after bariatric surgery - study protocol for a triple-blinded, blocked randomized, 12-month, parallel-group, placebo-controlled clinical trial. Trials. 2023 May 29;24(1):362. doi: 10.1186/s13063-023-07383-0.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Hafnia alvei HA4597™ in people with Obesity and Type 2 Diabetes, run by Universidade Nova de Lisboa at 1 site in Portugal.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 8 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Portugal. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Excess weight loss (time frame: At visit 1 (Baseline), visit 2 (3 months after bariatric surgery), visit 3 (6 months after bariatric surgery), visit 4 (9 months after bariatric surgery), visit 5 (12 months after bariatric surgery).). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05170867, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 May 2026.