Randomized Multicenter Cross-over Study to Compare the Effect of Physioneal 35 to 40 on the Protein Metabolism

Inclusion Criteria: * Patients who are males or non-pregnant females between the ages of 3 months and 18 years. * Patients who are on regular automated peritoneal dialysis due to end stage renal failure for at least 3 months. * Patients and/or their parents must be capable of understanding the purpose and risks of the study. * Patients and/or their parents (or guardians) who are willing to give written informed consent and willing to participate in and comply with the study protocol. Exclusion Criteria: * Use of pure lactate, amino acid or oligosaccharide solutions for peritoneal dialysis * Peritonitis episode less than 6 weeks before enrolment * Hypercalcemia (serum) \> 2.75 mmol/l in three independent measurements during 10 days * Severe secondary hyperthyroidism (iPTH \> 500 ng/l) * Renal anemia with hemoglobin (blood) \< 10 mg/dl * Impaired hepatic function (AST/SGOT or ALT/SGPT \> 2 times the upper limit of the reference range) * Patients who are participating in another study that requires Ethics Committee approval. Non-interventional studies are permitted. * Pregnant female patients, females of childbearing potential who are unwilling or unable to use adequate contraception methods. * Severe respiratory insufficiency * Malnourishment (body weight \< -2.5 SDS for height and gender) or severe deterioration of fat metabolism * Patients with a history of malignancy of any organ system, treated or untreated * Any surgical or medical condition which might significantly alter the absorption, distribution, metabolism, or excretion of the investigational product and the comparator, including * Major deterioration of the abdominal wall (e.g. dermal infections or burns, hernia) * Major deterioration of the abdominal cavity (e.g. ascites, ileus, adhesions, bowel perforation, defects of the diaphragm, tumours) * Patients with a history of viral infections such as HIV or hepatitis B, C.