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Improved Enzyme Protection Assay to Study Staphylococcus aureus Internalization and Intracellular Efficacy of Antimicrobial Compounds
Published on: September 8, 2021
A blinded, randomized, multicenter study of an intravenous Staphylococcus aureus immune globulin
D K Benjamin1, R Schelonka, R White
1Duke University Department of Pediatrics, Durham, NC 27710, USA. danny.benjamin@duke.edu
Insights
Altastaph effectively increased Staphylococcus aureus (S. aureus) antibody levels in very low birth weight (VLBW) infants. This investigational treatment was safe and well-tolerated, showing promise for preventing nosocomial infections in vulnerable neonates.
Area of Science:
- Neonatal Medicine
- Infectious Diseases
- Immunology
Background:
- Very low birth weight (VLBW) infants are highly susceptible to nosocomial infections, particularly those caused by Staphylococcus aureus.
- Staphylococcus aureus infections in neonates are frequently linked to capsular polysaccharide (CPS) types 5 and 8.
Purpose of the Study:
- To evaluate the safety and pharmacokinetics of Altastaph, a polyclonal human immunoglobulin G (IgG) with high opsonizing activity against S. aureus CPS types 5 and 8.
- To assess the ability of Altastaph to generate specific antibody levels against S. aureus CPS types 5 and 8 in VLBW infants.
Main Methods:
- A Phase 2, multicenter, randomized clinical trial involving VLBW neonates.
- Infants received either Altastaph (1000 mg/kg) or placebo (0.45% NaCl) via two intravenous infusions.
- Serum S. aureus CPS types 5 and 8 IgG levels were monitored pre-infusion and post-infusion for 28 days or until discharge.
Main Results:
- Altastaph administration led to significantly elevated geometric mean IgG levels against S. aureus CPS types 5 and 8, reaching 642 mcg/ml for type 5 after the second infusion.
- Placebo recipients maintained very low IgG levels (<2-5 mcg/ml).
- Adverse events were comparable between Altastaph and placebo groups, with similar rates of discontinuation (3%).
Conclusions:
- Altastaph successfully induced high concentrations of S. aureus types 5 and 8 CPS-specific IgG in VLBW neonates.
- The anti-staphylococcal hyperimmune globulin Altastaph demonstrated good tolerability in this vulnerable infant population.
- These findings support Altastaph's potential as a therapeutic agent against S. aureus infections in VLBW infants.
Objectives:
Very low birth weight (VLBW) infants are vulnerable to nosocomial infections and subsequent morbidity; including infections caused by Staphylococcus aureus: 85% of nosocomial S. aureus infections are caused by capsular polysaccharide (CPS) types 5 and 8. Altastaph is a polyclonal investigational human immunoglobulin G (IgG) with high levels of opsonizing S. aureus CPS types 5 and 8 IgG.
Methods:
A Phase 2 clinical trial to assess the safety and kinetics of Altastaph in VLBW infants. Neonates in this multicenter study were randomized to receive two identical 20 ml/kg i.v. infusions of either 0.45% NaCl placebo or 1000 mg Altastaph/kg. Each infant was followed for 28 days after the second infusion or until discharge. Serum S. aureus CPS types 5 and 8 IgG levels were measured preinfusion and at various times after each infusion.
Results:
Of 206 neonates, 158 received both infusions. Adverse events were similar in the two treatment groups. Six subjects (3% in each group) discontinued owing to an adverse event. Geometric mean anti-type 5 IgG levels were 402 and 642 mcg/ml 1 day following infusion of the first (day 0) and Second (day 14) doses, respectively, in neonates < or =1000 g and slightly higher in neonates 1001 to 1500 g. Trough levels before second infusion were 188 mcg/ml. Type 8 IgG levels were similar. Geometric mean IgG levels among placebo recipients were consistently <2 and <5 mcg/ml for types 5 and 8 in both weight groups. Three episodes of S. aureus bacteremia occurred in each arm.
Conclusions:
Infusion of Altastaph in VLBW neonates resulted in high levels of specific S. aureus types 5 and 8 CPS IgG. The administration of this anti-staphylococcal hyperimmune globulin was well tolerated in this population.
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