Rapid Point-of-Care Test Detects Anti-Infliximab Antibodies in Routine Clinical Practice

The development of antibodies to infliximab (ATI) is associated with a shorter duration of clinical response and more infusion reactions in patients. While detecting ATI is a key part of patient management for those receiving infliximab (IFX), current ATI detection techniques may require additional patient appointments for sample collection and processing in laboratory facilities, which is not only inconvenient for patients but can also delay test reporting by days or weeks; this delay has a negative effect on clinical decision making.

Spanish researchers recently reported reliable detection of ATI from venous or capillary blood using a rapid, point-of-care (POC) ATI test that allowed clinicians to detect ATI in a quick, decentralized mode that facilitated immediate POC decision making. Their results were presented during a poster session at the Annual European Congress of Rheumatology, June 14 to 17, 2017, in Madrid, Spain, and published in the June 2017 Annals of the Rheumatic Diseases.

Amagoia Ametzazurra of Progenika-Grifols Biopharma in Derio, Spain, and colleagues reported positive results of 2 prospective, observational studies evaluating and comparing the performance of Progenika’s Promonitor Quick Anti-IFX rapid point-of-care (POC) test for anti-infliximab antibodies in 90 rheumatology and gastroenterology patients who were receiving infliximab (Remicade) or its biosimilar (Inflectra/Remsima).

Progenika’s Promonitor Quick Anti-IFX POC test is a qualitative immunochromatographic assay based on lateral flow technology to detect ATI (including ATI associated with biosimilar Inflectra/Remsima) in either fingerprick, serum, or venous whole blood. Patients were also tested using the enzyme-linked immunosorbent assay (ELISA) reference technique.

Consecutive patients, who were either initiating treatment or undergoing maintenance treatment, were recruited and tested in La Paz and Basurto University hospitals in Spain using the investigational test in capillary and venous whole blood specimens immediately before the infusion. ATI test results were read visually using the POC tests within 30 minutes, just prior to the patients’ starting infusions. Trough sera were also collected for subsequent analysis with the rapid test and benchmarked with the Promonitor—Anti-IFX ELISA. Follow-up was conducted for 6 months. ELISA quantitative results were categorized as either positive or negative to allow for comparison with the qualitative rapid test.

From a total of 137 visits in the 6 months of follow-up, researchers collected 137 sera, 137 fingerprick, and 71 venous whole blood samples from the 90 patients. Overall, 8 (8.9%) patients developed ATI (5 patients with ankylosing spondylitis, 1 with Crohn’s disease, 1 with ulcerative colitis, and 1 with juvenile idiopathic arthritis). ATI were detected in 5 patients treated with infliximab and in 3 treated with infliximab biosimilar.

There were 100% and 99% agreements, respectively, between fingerprick versus venous whole blood and fingerprick versus serum, measured with the rapid POC test. Positive and negative agreements between the POC test and the ELISA were 91% and 99%, respectively. Positive and negative agreements between the ELISA and the POC test in serum were 100% and 99%, respectively.

“ATI can be reliably detected in either venous or capillary circulation,” the researchers concluded. “Results show an almost perfect agreement between specimens and with the reference ELISA technique.”

Amagoia Ametzazurra and several other study authors disclose that they are employees of Progenika Grifols.