Immunoglobulin treatment and clinical outcomes: data from the Ontario Immunoglobulin Treatment program multicenter...

The therapeutic use of immunoglobulin (IG) is increasing and accounts for the largest expenditure in the Canadian Blood Services budget. However, more granular data on IG utilization is limited.

To describe IG treatment indications, dosing characteristics, and clinical outcomes in patients enrolled in the Ontario IG Treatment (ONIT) program, a government-funded pilot clinical program with a case registry.

A longitudinal descriptive study was conducted on ONIT registry participants from June 1, 2020 to March 31, 2024.

Six hundred ninety-three consenting participants were included; 429 (61.9%) were female; median [Q1, Q3] age was 62 [47, 71] years; 47 (6.8%) passed away during the study period. Of 693, 658 (94.9%) were receiving IG treatment: 544 (82.7%) on SCIG and 114 (17.3%) on IVIG. Treatment indications were primary immune deficiency (PID) (299, 43.1%), secondary immune deficiency (SID) (348, 50.2%), and immune-mediated disease (IMD) (46, 6.7%). The median dose was 0.48 [0.42, 0.57] and 0.52 [0.44, 0.64] g/kg/4 weeks, for SCIG and IVIG, respectively. Seventy-three patients transitioned from IVIG to SCIG, with the dose adjusted to clinical response. The IVIG:SCIG conversion ratios were 1:1, 1:0.9, and 1:1.2 for PID, SID, and IMD, respectively. Only 33 (5.0%) stopped IG during the study. There was a 78.4% reduction in infections and over 90% reduction in emergency room visits and hospitalizations in PID and SID. Most patients (89.4%) reported improved health after starting IG therapy.

The study provides insights into the current landscape of IG utilization, which may inform health system research and support healthcare delivery planning.