Fiber-Boost Randomized Controlled Trial

Recruiting now · Not applicable

Conditions studied: Non-Small Cell Carcinoma of Lung

In brief

In the present study 'Fiber-Boost', we investigate how a high-fiber diet affects the immunotherapy of advanced lung cancer and what effects it has on the gut microbiome (i.e., the bacteria in the gut) as well as the immune system. Study participants will be assigned to either a test group or a control group. Only patients in the test group will undergo a high-fiber diet. The study lasts 6 weeks per patient and will be conducted at 4 centers within Switzerland. A total of 42 patients are planned to be included in the study.

Key facts

Study ID: NCT07483112
Run by: Cantonal Hospital of St. Gallen
People needed: 42
Starts: 2025-10-07
Expected to finish: 2027-12-31
Last updated by the study team: 2026-03-19

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

Age ≥18 years
Written informed consent according to Swiss law and ICH/GCP regulations before inclusion and prior to any trial-specific procedures
Histologically or cytologically confirmed NSCLC
Advanced or recurrent NSCLC not amenable to curative treatment
PD-L1 expression ≥50% (TPS) determined by an approved IHC test
No actionable genetic alterations in genes such as EGFR, ALK, ROS1, HER2, BRAF, RET, MET, NTRK
First-line palliative PD-1/PD-L1-targeted monotherapy at a 3-weekly schedule indicated per local investigator
Willingness and ability to undergo study interventions
ECOG performance status 0-2
Adequate organ function:
Hemoglobin ≥70 g/L, platelet count ≥50 G/L, granulocytes ≥1 G/L
Bilirubin, ALT, AST ≤3 x ULN
Glomerular filtration rate (Cockroft-Gault) ≥30 mL/min/1.73m²
Measurable or evaluable disease per RECIST 1.1
Patients with CNS metastases are eligible, provided there is no requirement for corticosteroids as therapy for CNS disease and no evidence of clinical progression
Women with child-bearing potential use effective contraception (two independent methods), are not currently pregnant or lactating, and agree to not become pregnant during the trial treatment and during 3 months thereafter. A negative pregnancy test in either urine or blood is required for women with child-bearing potential before trial inclusion.
Men who are not sterile agree to use contraceptive methods (condoms) or abstain from sexual intercourse during the trial treatment and 3 months thereafter.

You may not qualify if…

History of malignancy, unless in remission for at least 3 years before inclusion with the exception of pT1-2 prostate cancer Gleason score <6, adequately treated cervical carcinoma in situ or localized non-melanoma skin cancer
Adjuvant or additive systemic ICB treatment within 6 months prior to inclusion
Systemic treatment with an antibiotic within 10 days of ICB treatment/HFD intervention start
Concomitant immunosuppressive drugs including corticosteroids at a daily dose of ≥10mg prednisone equivalents, methotrexate, azathioprine, TNF-α inhibitors
Concurrent treatment with other experimental drugs or other anticancer therapy
Major surgical procedures within 14 days prior to inclusion as judged by the investigator
Active autoimmune disease requiring systemic immunosuppressive treatment that is seen as contraindication for the use of PD-1/PD-L1-targeted monoclonal antibodies
Uncontrolled diabetes mellitus
Severe or uncontrolled cardiovascular disease
Any other serious underlying medical, psychiatric, psychological, familial or geographical condition, which in the judgment of the investigator may interfere with the planned staging, treatment and follow-up, affect patient compliance or place the patient at high risk from treatment-related complications
Had an allogeneic tissue/solid organ transplant
Ongoing supplementation with OptiFibre® or another fiber supplement

Where it is running

HOCH Health Ostschweiz, Cantonal Hospital St.Gallen — Sankt Gallen, Switzerland (enrolling)
Universitätsspital Basel — Basel, Switzerland
Kantonsspital Graubünden — Chur, Switzerland
Kantonsspital Winterthur — Winterthur, Switzerland

Full record on ClinicalTrials.gov

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