The primary objective of this randomized trial is to test whether a treatment with canakinumab is superior to placebo in patients with postprandial hypoglycemia after bariatric surgery, that is if it improves health related quality of life (mentally or physically) or reduces the risk of hypoglycemic events.

Postprandial hypoglycemia is a debilitating medical complication after bariatric surgery for which no approved pharmacological treatment exists. In a former study, the IL-1 receptor antagonist Anakinra statistically significantly reduced the number of symptomatic hypoglycemia.

This randomized clinical trial is to directly evaluate clinical outcomes and patient-relevant benefits of treatment with the IL-1 receptor canakinumab over 28 days. The primary objective of this randomized trial is to test whether a treatment with canakinumab is superior to placebo in patients with postprandial hypoglycemia after bariatric surgery, that is if it improves health related quality of life (mentally or physically) or reduces the risk of hypoglycemic events.

For each subject, a maximum study duration of four months is anticipated with: screening visit 1 (1 h), screening phase (10-day screening phase for postprandial hypoglycemia using a blinded continuous glucose monitoring system (CGMS, Dexcom G6)), randomization/starting visit (visit 2, 1.5 h) followed by a 28 days intervention period with two additional study days (visit 3 and 4, 0.5 h, change of blinded continuous glucose monitoring system (CGFS sensor), diary documentation, adverse events) and end of treatment visit (visit 5). A follow-up visit will be done two months after the end of the treatment phase.

Inclusion Criteria:

• Patients after bariatric surgery (i.e. sleeve gastrectomy, Roux-en-Y gastric bypass, omega-loop bypass, biliopancreatic diversion) with documented hypoglycemia, i. e. < 3.0 mmol/l and at least 5 hypoglycemic episodes per week despite dietary modification
• For women with child-bearing potential, willingness to use contraceptive measures adequate to prevent pregnancy during the study
• Informed Consent as documented by signature

Exclusion Criteria:

• Any type of diabetes mellitus according to ADA criteria
• Intolerance to the study drug
• Signs of current infection
• Any use of immunosuppressive medication
• Use of any drug therapy for postbariatric hypoglycemia apart from acarbose (all remaining drugs have to be discontinued four half-life times before screening phase)
• Neutropenia (leukocyte count < 1.5 × 109/L or ANC < 0.5 × 109/L)
• Anemia (hemoglobin < 11 g/dL for males, < 10 g/dL for females)
• Clinically significant kidney or liver disease (creatinine > 1.5 mg/dL, AST/ALT > 2 × ULN, alkaline phosphatase > 2 × ULN, or total bilirubin [tBili] > 1.5 × ULN)
• Uncontrolled congestive heart failure
• Uncontrolled malignant disease
• Currently pregnant or breastfeeding
• Known or suspected non-compliance, drug or alcohol abuse
• Meeting the criteria for vulnerability (e.g. participants incapable of judgment or participants under tutelage)
• Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc.
• Participation in another clinical trial using investigational drugs in the last 30 days or planned participation in the next 60 days
• Previous enrolment into the current study,
• Enrolment of the investigator, his/her family members, employees and other dependent persons

Results will be published in a relevant scientific journal and communicated to participants and relevant institutions through dissemination activities. Individual data are accessible on request.

Both subjects and investigators will be blinded. A nurse independent of the research group will be responsible for treatment blinding and preparation of trial drugs throughout the study.