Compassionate Use Experience with High Titer RSV Immunoglobulin (RSV-IVIG) in RSV Infected Immunocompromised Persons Open Access

Background. Respiratory syncytial virus (RSV) may cause fatal lower respiratory tract infection (LRT) in immunocompromised patients. Presently, therapeutic options are limited. Various forms of ribavirin with or without standard intravenous gammaglobulin (IVIG) are frequently given although efficacy is debated. Infusion of IVIG with high levels of neutralizing antibody against RSV may offer clinical benefit in these patients.

Methods. RI-001 contains standardized levels of high titer anti RSV neutralizing antibody and was provided for compassionate use to 15 patients with documented RSV LRTI who either failed conventional therapy or were at significant risk of progression. Patients were treated on day 1 with RI-001 1,500mg/kg, followed 2 days later with 750 mg/kg. Sera were collected pre and post each infusion and measured for RSV neutralizing antibody by microneutralization assay. Patient data were collected and analyzed for safety related to the infusion of RI-001, and clinical outcomes.

Results. Patients ranged from 9 months to 75 years, 60% were male and included the following medical conditions: bone marrow or hematopoietic stem cell transplant recipients (9), hematologic malignancy (3), severe combined immunodeficiency syndrome (1), liver transplant (1), interstitial lung disease (1). Administration was well tolerated with no drug related serious adverse events. Pre infusion neutralizing titers ranged from 51 to 1765 GMT (mean 646 ± 519), and all patients with serum available demonstrated at least a 4-fold rise (mean 6,410 ± 4,470) at 5–10 days post-infusion with most persisting 18– 33 days post-infusion. Eleven of 15 showed improvement of respiratory symptoms and were discharged from the hospital. Days from positive RSV test to RI-001 treatment was shorter in survivors compared to non-survivors (4.4 ± 2.8 vs 20.3 ± 21.0 days, P = .02). Patients with respiratory failure prior to receiving RI-001 had a significantly higher death rate compared to those who were not intubated prior to treatment (75% vs 0%, P = .009).

Conclusion. Administration of RI-001 was well tolerated and resulted in significant increases in serum neutralizing antibody titers to RSV. Our data suggest that early identification and treatment with RI-001 may offer clinical benefit.

Disclosures. A. R. Falsey, ADMA Biologics: Research Contractor, Fee for service laboratory work C. Koval, ADMA Biologics: Grant Investigator, Grant recipient J. Mond, ADMA Biologics: Employee, Salary

Author notes