Pseudo-anaphylaxis to Polyethylene Glycol (PEG)-Coated Liposomes: Roles of Anti-PEG IgM and Complement Activation in a Porcine Model of Human Infusion Reactions.

Gergely Tibor Kozma,Yechezkel Barenholz,Rudolf Urbanics,László Rosivall,Erik Örfi,László Dézsi,Tom Eirik Mollnes,Tamás Fülöp,János Szebeni,Tamás Mészáros,Yaelle Bavli,Ildikó Vashegyi

doi:10.1021/acsnano.9b03942

Abstract

Polyethylene glycol (PEG)-coated nanopharmaceuticals can cause mild to severe hypersensitivity reactions (HSRs), which can occasionally be life threatening or even lethal. The phenomenon represents an unsolved immune barrier to the use of these drugs, yet its mechanism is poorly understood. This study showed that a single i.v. injection in pigs of a low dose of PEGylated liposomes (Doxebo) induced a massive rise of anti-PEG IgM in blood, peaking at days 7-9 and declining over 6 weeks. Bolus injections of PEG-liposomes during seroconversion resulted in anaphylactoid shock (pseudo-anaphylaxis) within 2-3 min, although similar treatments of naı̈ve animals led to only mild hemodynamic disturbance. Parallel measurement of pulmonary arterial pressure (PAP) and sC5b-9 in blood, taken as measures of HSR and complement activation, respectively, showed a concordant rise of the two variables within 3 min and a decline within 15 min, suggesting a causal relationship between complement activation and pulmonary hypertension. We also observed a rapid decline of anti-PEG IgM in the blood within minutes, increased binding of PEGylated liposomes to IgM+ B cells in the spleen of immunized animals compared to control, and increased C3 conversion by PEGylated liposomes in the serum of immunized pigs. These observations taken together suggest rapid binding of anti-PEG IgM to PEGylated liposomes, leading to complement activation via the classical pathway, entailing anaphylactoid shock and accelerated blood clearance of liposome-IgM complexes. These data suggest that complement activation plays a causal role in severe HSRs to PEGylated nanomedicines and that pigs can be used as a hazard identification model to assess the risk of HSRs in preclinical safety studies.

Highlights

Polyethylene glycols (PEGs), highly hydrated bulky polymers in the 0.5−40 kDa range, are widely used to improve the therapeutic efficacy of drug carrier liposomes and proteins by extending their circulation time
An unresolved issue with such PEGylated nanopharmaceuticals is their recognition by the immune system manifested in non-IgE-mediated hypersensitivity reactions (HSRs), an adverse event commonly called infusion reaction.[1−7] PEGylated nanomedicines that have been reported to cause such reactions include PEGylated liposomal doxorubicin (Doxil/Caelyx),[8] PEGylated G-CSF,[9] PEGylated erythropoetin,[10] PEGylated recombinant human factor VIII (Adynovate),[11] and PEGylated phenylalanine ammonia lyase,[12] with at least three formulations withdrawn from clinical use partly because of severe HSRs: PEGylated EPOmimetic peptide,[13] PEGylated urate oxidase,[14] and a PEGylated IXa blocker RNA aptamer.[15]
On the basis of a long list of evidence for a causal role of complement activation in certain liposome-induced HSRs (Supplement Table 1) we proposed earlier that complement activation-related pseudoallergy (CARPA) represents a major mechanism of infusion reactions to a variety of nanoparticulate drugs and agents.[21,22]

Summary

Introduction

Polyethylene glycols (PEGs), highly hydrated bulky polymers in the 0.5−40 kDa range, are widely used to improve the therapeutic efficacy of drug carrier liposomes and proteins by extending their circulation time. In most cases the problem spontaneously resolves or can be controlled; occasionally, the reaction can escalate into pseudo-anaphylaxis, a severe, occasionally lethal form of infusion reactions resembling anaphylaxis without IgE playing a role. It is known as anaphylactoid reaction, or anaphylactoid shock. By providing evidence for a causal relationship among the induction of anti-PEG antibodies, complement activation, and pseudo-anaphylaxis, the present data highlight the mechanism of Doxil-induced severe HSRs and use of the pig model in understanding and predicting this type of immune toxicity of PEGylated nanopharmaceuticals

Methods

Results

Conclusion