Safety, potential efficacy, and pharmacokinetics of specific polyclonal immunoglobulin F(ab')2 fragments against avian influenza A (H5N1) in healthy volunteers: a single-centre, randomised, double-blind, placebo-controlled, phase 1 study

Immunoglobulin fragment F(ab’)2against RBD potently neutralizes SARS-CoV-2 in vitro

“…This is a reminder of developing broad-spectrum drugs and vaccines 26 , when the pace of specific drug development is not fast enough to cope with. Prior experience in infectious disease control suggests that antiviral serum obtained from hyper immune equine plasma has long been used for the treatment of life threatening viral diseases 27 .…”

Benefits of using heterologous polyclonal antibodies and potential applications to new and undertreated infectious pathogens

“…A phase 1 study in 16 healthy young human males aged 21-40 years who received intramuscular polyclonal F(ab ) 2 to HPAI H5N1 yielded no serious adverse events, no changes in blood or urinary parameters, and only one febrile reaction, likely related to the product; there was also evidence of clinical benefit as assessed by seroneutralising and haemagglutination inhibition testing of the subjects' plasma samples [40]. As ethically no placebo-controlled efficacy studies in humans can be performed, further effectiveness data will have to be gathered from compassionate case-based use.…”

“…Half-time of elimination (t1/2) of the product in the plasma compartment was analyzed after intravenous (IV) administration of F(ab ) 2 against avian influenza A H5N1 in 3 healthy volunteers receiving 1 dose and in 10 healthy volunteers receiving 5 doses [40]. The plasmatic elimination of F(ab ) 2 after one IV infusion had a mean t1/2 of 16.77 h and after 5 infusions 24 h apart, a mean of 10.89 h. These results indicated the persistence of equine F(ab ) 2 in the plasma for the duration of the therapeutic protocol with evidence of a slight accumulation between day 1 and day 5.…”

Anti-Ebola therapies based on monoclonal antibodies: current state and challenges ahead

“…The use of properly engineered mAb fragments, instead of full-length mAbs, is a therapeutic alternative that has yet to be investigated for Ebola. The use of antibody fragments to neutralize viruses or prevent virus infection is not novel; proof of concept experiments have shown their potential applications in the context of different viral infections such us HIV (Lülf et al, 2014), Influenza A H1N5 (Bal et al, 2015), SARS (Sui et al, 2004), HPV (Culp et al, 2007), and West Nile virus (Gould et al, 2005). A recent contribution by Rodríguez-Martínez et al (2015) offers proof-of-principle of the application of three anti-EBOV mAb fragments, containing the variable regions the mAbs KZ52, 13C6, and 13F6, in immunological assays to specifically detect recombinant GP.…”