Open-Label Phase II Study to Evaluate the Efficacy and Safety of IdeS in Anti-GBM Disease

This study will evaluate the safety and tolerability of IdeS in patients with severe anti-glomerular basement membrane (anti-GBM) disease receiving standard of care consisting of pulse-methylprednisolone, oral prednisolone and intravenous cyclophosphamide combined with plasma exchange (PLEX).

This is an Open-Label Phase 2 Study to Evaluate the Efficacy and Safety of IdeS in anti-GBM disease (Goodpasture's disease, i.e. GP) with Adverse Renal Prognosis. The primary efficacy objective is to evaluate the efficacy of an IdeS based regimen to salvage independent renal function measured as no need for dialysis at 6 months after IdeS treatment. The primary safety objective of this study is to evaluate the safety and tolerability of IdeS in patients with severe anti-GBM disease on background of standard care consisting of pulse-methylprednisolone, oral prednisolone and intravenous cyclophosphamide (CYC) combined with plasma exchange (PLEX). The patients will be followed during 6 months according to the study visit plan.

Eligibility Criteria:
Inclusion Criteria:

1. Anti-GBM antibodies detected by ELISA above a level that is considered toxic by the investigator using local laboratory. Patients double-positive for anti-GBM and anti-neutrophil cytoplasmic antibodies (ANCAs) may be entered in the trial, but only if their level of anti-GBM antibodies fulfil the criteria listed above.
2. Estimated glomerular filtration rate (eGFR) \<15 ml/min/1.73 m\^2 (by modification of diet in renal disease (MDRD) equation) or if the patient is non-responsive to standard treatment, and has lost \>15 ml/min/1.73 m\^2 after start of treatment
3. Haematuria on dipstick and/or urinary sediment
4. Male or female patients aged at least 18 years; Female patients of childbearing potential may participate if highly effective contraception is used during the study, according to Clinical Trials Facilitation and Coordination Group (CTFG) guidance \[18\], see also section 4.9 (pregnancy test should be performed before inclusion).
5. Willing and able to give written Informed Consent and to comply with the requirements of the study protocol; and
6. Judged to be otherwise healthy by the Investigator, based on medical history, physical examination, and clinical laboratory assessments. Patients with clinical laboratory values that are outside of normal limits (other than those specified in the Exclusion Criteria) and/or with other abnormal clinical findings that are judged by the Investigator not to be of clinical significance, may be entered into the study.

Exclusion Criteria:

1. Anuria for more than 2 days (less than 200 ml during last 48 hours);
2. Dialysis dependency for more than 5 days (maximum 3 sessions before signing informed consent);
3. Ongoing moderate to severe pulmonary haemorrhage (or having ceased within the last two weeks), defined as requiring assisted ventilation, oxygen or blood transfusions.
4. Pregnancy.
5. Symptomatic congestive heart failure (NYHA class 2-4) and requiring prescription medication or clinically evident peripheral edema of cardiac origin;
6. Myocardial infarction, unstable angina or stroke within 3 months prior to screening;
7. Ongoing bacterial infection requiring antibiotic therapy or viral infection with Hepatitis B, C or HIV (up to 3 months old negative test results are accepted); or active tuberculosis as indicated by chest x-ray.
8. Patients should not have received investigational drugs within 30 days prior to screening or within 4 half-lives (whichever is longer); and
9. History or presence of any medical condition or disease which, in the opinion of the Investigator, may place the subject at unacceptable risk for study participation.