Intravenous immunoglobulin treatment for chronic inflammatory demyelinating polyneuropathy usually startswith a 2.0 g/kg induction dose followed by 1.0 g/kg maintenance doses every 3 weeks. No dose-ranging studies withintravenous immunoglobulin maintenance therapy have been published.
The Progress in Chronic Inflammatory Demyelinating polyneuropathy (ProCID) study was a prospective, double-blind, randomized, parallel-group, multicentre, phase III study investigating the efficacy and safety of 10% liquid intravenous immunoglobulin (PanzygaV R ) in patients with active chronic inflammatory demyelinating polyneuropathy. Patients were randomized 1:2:1 to receive the standard intravenous immunoglobulin induction dose andthen either 0.5, 1.0 or 2.0 g/kg maintenance doses every 3 weeks.
The primary end point was the response rate in the 1.0 g/kg group, defined as an improvement 51 point in adjusted Inflammatory Neuropathy Cause and Treatment score at Week 6 versus baseline and maintained at Week 24. Secondary end points included dose response and safety. This trial was registered with EudraCT (Number 2015–005443-14) and clinicaltrials.gov (NCT02638207).
Between August 2017 and September 2019, the study enrolled 142 patients. All 142 were included in the safety analyses. As no post-infusion data were available for three patients, 139 were included in the efficacy analyses, ofwhom 121 were previously on corticosteroids.
The response rate was 80% (55/69 patients) [95% confidence interval(CI): 69–88%] in the 1.0 g/kg group, 65% (22/34; CI: 48–79%) in the 0.5 g/kg group, and 92% (33/36; CI: 78–97%) in the2.0 g/kg group. While the proportion of responders was higher with higher maintenance doses, logistic regression analysis showed that the effect on response rate was driven by a significant difference between the 0.5 and 2.0 g/kg groups, whereas the response rates in the 0.5 and 2.0 g/kg groups did not differ significantly from the 1.0 g/kg group.
Fifty-six per cent of all patients had an adjusted Inflammatory Neuropathy Cause and Treatment score improvement 3 weeks after the induction dose alone.
Treatment-related adverse events were reported in 16 (45.7%),32 (46.4%) and 20 (52.6%) patients in the 0.5, 1.0 and 2.0 g/kg dose groups, respectively. The most common adverse reaction was headache. There were no treatment-related deaths.
Intravenous immunoglobulin (1.0 g/kg) was efficacious and well tolerated as maintenance treatment for patientswith chronic inflammatory demyelinating polyneuropathy. Further studies of different maintenance doses ofintravenous immunoglobulin in chronic inflammatory demyelinating polyneuropathy are warranted.
