Validation and life-cycle management of a quantitative ligand-binding assay for the measurement of Nulojix(®), a CTLA-4-Fc fusion protein, in renal and liver transplant patients.
BACKGROUND
Nulojix(®) is a fusion protein composed of the Fc portion of a human IgG1 linked to the extracellular modified domain of CTLA-4. Nulojix differs from another Bristol Myers Squibb product, Orencia(®) by two amino acids and was approved by the FDA on 15 June 2011 for the prophylaxis of organ rejection in adult patients receiving kidney transplant.


RESULTS
A sandwich ELISA utilizing two monoclonal antibodies against CTLA-4 was employed for Nulojix quantification and pharmacokinetic analysis. At least 17 analysts have qualified on the assay and contributed to reportable results over the last 7 years. In-study accuracy and precision demonstrate suitable performance: %bias within -4 to 4%, %CV ≤13% and total error within 6-15%. Incurred sample reanalysis was completed in applicable disease-state populations. The assay was automated and validated in additional clinical matrices (ascites and urine) and Nulojix quantification was validated in the presence of clinically relevant co-administered compounds. In 2011, the biotinylation procedure was modified meriting a regression change (quadratic to 4-parameter logistic) and associated partial validation.


CONCLUSIONS
This long-term pharmacokinetic program provides a good example of the dynamic clinical environment and adaptation requirements of ligand-binding assays.
Bristol-Myers Squibb, Route 206 & Province Line Rd, Princeton, NJ, USA. heather.myler@bms.com
Heather A
HA
Myler
Kelli R
KR
Phillips
Huijin
H
Dong
Edward
E
Tabler
Mehmooda
M
Shaikh
Valarie
V
Coats
Laura
L
Hay
Richard
R
Tacey
Bruce
B
Stouffer
D000069594:Abatacept; D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D018796:Immunoconjugates / Q000097:blood* / Q000493:pharmacokinetics; D007166:Immunosuppressive Agents / Q000097:blood* / Q000493:pharmacokinetics; D016030:Kidney Transplantation; D016031:Liver Transplantation; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D011993:Recombinant Fusion Proteins / Q000097:blood* / Q000493:pharmacokinetics; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D018796:Immunoconjugates; D007166:Immunosuppressive Agents; D011993:Recombinant Fusion Proteins; D000069594:Abatacept