Immediate hypersensitivity reaction to pegylated liposomal doxorubicin: management and outcome in four patients

The interplay between PEGylated nanoparticles and blood immune system

During the last two decades, an increasing number of reports have pointed out that the immunogenicity of polyethylene glycol (PEG) may trigger accelerated blood clearance (ABC) and hypersensitivity reaction (HSR) to PEGylated nanoparticles, which could make PEG modification counterproductive. These phenomena would be detrimental to the efficacy of the load and even life-threatening to patients. Consequently, further elucidation of the interplay between PEGylated nanoparticles and the blood immune system will be beneficial to developing and applying related formulations. Many groups have worked to unveil the relevance of structural factors, dosing schedule, and other factors to the ABC phenomenon and hypersensitivity reaction. Interestingly, the results of some reports seem to be difficult to interpret or contradict with other reports. In this review, we summarize the physiological mechanisms of PEG-specific immune response. Moreover, we speculate on the potential relationship between the induction phase and the effectuation phase to explain the divergent results in published reports. In addition, the role of nanoparticle-associated factors is discussed based on the classification of the action phase. This review may help researchers to develop PEGylated nanoparticles to avoid unfavorable immune responses based on the underlying mechanism.

Hidden Dangers: Recognizing Excipients as Potential Causes of Drug and Vaccine Hypersensitivity Reactions

Excipients are necessary as a support to the active ingredients in drugs, vaccines, and other products, and they contribute to their stability, preservation, pharmacokinetics, bioavailability, appearance, and acceptability. For both drugs and vaccines, these are rare reactions; however, for vaccines, they are the primary cause of immediate hypersensitivity. Suspicion for these "hidden dangers" should be high, in particular, when anaphylaxis has occurred in association with multiple chemically distinct drugs. Common excipients implicated include gelatin, carboxymethylcellulose, polyethylene glycols, and products related to polyethylene glycols in immediate hypersensitivity reactions and propylene glycol in delayed hypersensitivity reactions. Complete evaluation of a suspected excipient reaction requires detailed information from the product monograph and package insert to identify all ingredients that are present and to understand the function and structure for these chemicals. This knowledge helps develop a management plan that may include allergy testing to identify the implicated component and to give patients detailed information for future avoidance of relevant foods, drugs, and vaccines. Excipient reactions should be particularly considered for specific classes of drugs where they have been commonly found to be the culprit (eg, corticosteroids, injectable hormones, immunotherapies, monoclonal antibodies, and vaccines). We provide a review of the evidence-based literature outlining epidemiology and mechanisms of excipient reactions and provide strategies for heightened recognition and allergy testing.

Complement-mediated hypersensitivity reactions to an amphotericin B-containing lipid complex (Abelcet) in pediatric patients and anesthetized rats: Benefits of slow infusion

Intravenous administration of lipid-based nanodrugs can cause hypersensitivity, also known as infusion reactions (IRs), that can be attenuated by slow infusion in adult patients. We studied the role of infusion rate and complement (C) activation in IRs in pediatric patients treated with Abelcet, and also in anesthetized rats. IRs were observed in 6 out of 10 (60%) patients who received Abelcet infusion in 4 h or less, while no patients who received the infusion in 6 h showed C activation or IRs. The rat model indicated an inverse relationship between infusion speed and Abelcet-induced hypotension, taken as an experimental endpoint of IRs, while the rise of C3a in blood, an index of C activation, directly correlated with hypotension. The results suggest that pediatric patients are more prone to produce IRs, and that the optimal infusion time of Abelcet may be much longer than the presently recommended 2 h.

Hypersensitivity reaction to pegylated liposomal doxorubicin administration for Mullerian carcinoma in Japanese women

AIM

PEGylated liposomal doxorubicin (PLD) is a therapeutic agent for gynecological malignancy. Hypersensitivity reaction (HSR) is a major adverse effect that usually disappears after halting administration of PLD. Premedication is usually not necessary before administration of PLD to prevent HSR. Here, we evaluated the frequency of HSR during administration of PLD following premedication in Japanese women.

METHODS

We performed PLD administration in 78 patients (386 cycles) between 2013 and 2018. Granisetron hydrochloride and dexamethasone sodium phosphate were administered 30 min before PLD administration. Then, PLD (40 or 30 mg/m² combined usage with carboplatin) was administered. We retrospectively reviewed the medical records of 78 patients and examined the frequency of HSR.

RESULTS

Seven of 78 (9%) patients showed HSR by PLD administration following premedication. One patient showed cardiopulmonary arrest in 13 min after PLD administration (grade 4). The other six patients showed grade 2 HSR. All patients developed HSR in the first course. The incidence of HSR was significantly higher in patients with allergic history than in patients without allergic history (p = 0.0151).

CONCLUSIONS

Clinicians should be aware of the potential for HSR in patients administered PLD, particularly those with allergic history and those receiving the first cycle of PLD, even following premedication.

Nanoparticle Toxicology

Nanoparticles from natural and anthropogenic sources are abundant in the environment, thus human exposure to nanoparticles is inevitable. Due to this constant exposure, it is critically important to understand the potential acute and chronic adverse effects that nanoparticles may cause to humans. In this review, we explore and highlight the current state of nanotoxicology research with a focus on mechanistic understanding of nanoparticle toxicity at organ, tissue, cell, and biomolecular levels. We discuss nanotoxicity mechanisms, including generation of reactive oxygen species, nanoparticle disintegration, modulation of cell signaling pathways, protein corona formation, and poly(ethylene glycol)-mediated immunogenicity. We conclude with a perspective on potential approaches to advance current understanding of nanoparticle toxicity. Such improved understanding may lead to mitigation strategies that could enable safe application of nanoparticles in humans. Advances in nanotoxicity research will ultimately inform efforts to establish standardized regulatory frameworks with the goal of fully exploiting the potential of nanotechnology while minimizing harm to humans.

Immunological and Toxicological Considerations for the Design of Liposomes

Liposomes hold great potential as gene and drug delivery vehicles due to their biocompatibility and modular properties, coupled with the major advantage of attenuating the risk of systemic toxicity from the encapsulated therapeutic agent. Decades of research have been dedicated to studying and optimizing liposomal formulations for a variety of medical applications, ranging from cancer therapeutics to analgesics. Some effort has also been made to elucidate the toxicities and immune responses that these drug formulations may elicit. Notably, intravenously injected liposomes can interact with plasma proteins, leading to opsonization, thereby altering the healthy cells they come into contact with during circulation and removal. Additionally, due to the pharmacokinetics of liposomes in circulation, drugs can end up sequestered in organs of the mononuclear phagocyte system, affecting liver and spleen function. Importantly, liposomal agents can also stimulate or suppress the immune system depending on their physiochemical properties, such as size, lipid composition, pegylation, and surface charge. Despite the surge in the clinical use of liposomal agents since 1995, there are still several drawbacks that limit their range of applications. This review presents a focused analysis of these limitations, with an emphasis on toxicity to healthy tissues and unfavorable immune responses, to shed light on key considerations that should be factored into the design and clinical use of liposomal formulations.

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

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.

Theranostic Imaging May Vaccinate against the Therapeutic Benefit of Long Circulating PEGylated Liposomes and Change Cargo Pharmacokinetics

The enhanced permeability and retention (EPR) effect increases tumor accumulation of liposomal chemotherapy and should, in theory, increase anticancer effects and lower toxicity. Unfortunately, liposomal chemotherapy has generally not met the expected potential, perhaps because the EPR effect is not ubiquitous. PET imaging using radiolabeled liposomes can identify cancers positive for the EPR effect. In the current study, we show in clinical canine cancer patients that repeated imaging with radiolabeled liposomes (⁶⁴Cu-liposome) induces the accelerated blood clearance (ABC) phenomenon. This was observed even with very long intervals between PEGylated liposome injections, which contradict previous reporting in experimental animal models. The induction of ABC may be devastating for the theranostic use of liposomal imaging, as this could vaccinate patients against therapeutic efficacy. To investigate and solve this important problem, an additional study part was designed in which rats were subjected to repeated liposomal administrations, including stealth ⁶⁴Cu-liposome PET imaging and Caelyx chemotherapy. Most importantly, it was found that, by increasing the lipid dose at the first injection or by supplying a small predose before the second ⁶⁴Cu-liposome injection, ABC could be prevented. Importantly, signs of liposome tracer breakdown with subsequent renal excretion were observed. These findings highlight the importance of the ABC phenomenon for liposomal predictive imaging in a clinically relevant setting and show that carefully planned application is central to avoid potential detrimental effects on patient benefit.