Infusion reactions to adeno-associated virus (AAV)-based gene therapy: Mechanisms, diagnostics, treatment and review of the literature.

The use of adeno-associated virus (AAV) vectors in gene therapy has demonstrated great potential in treating genetic disorders. However, infusion-associated reactions (IARs) pose a significant challenge to the safety and efficacy of AAV-based gene therapy. This review provides a comprehensive summary of the current understanding of IARs to AAV therapy, including their underlying mechanisms, clinical presentation, and treatment options. Toll-like receptor activation and subsequent production of pro-inflammatory cytokines are associated with IARs, stimulating neutralizing antibodies (Nabs) and T-cell responses that interfere with gene therapy. Risk factors for IARs include high titers of pre-existing Nabs, previous exposure to AAV, and specific comorbidities. Clinical presentation ranges from mild flu-like symptoms to severe anaphylaxis and can occur during or after AAV administration. There are no established guidelines for pre- and postadministration tests for AAV therapies, and routine laboratory requests are not standardized. Treatment options include corticosteroids, plasmapheresis, and supportive medications such as antihistamines and acetaminophen, but there is no consensus on the route of administration, dosage, and duration. This review highlights the inadequacy of current treatment regimens for IARs and the need for further research to improve the safety and efficacy of AAV-based gene therapy.

Reducing agalsidase beta infusion time in Fabry patients: low incidence of antibody formation and infusion-associated reactions in an Italian multicenter study.

BACKGROUND: Fabry disease is a rare progressive X-linked lysosomal storage disease caused by mutations in the GLA gene that encodes α-galactosidase A. Agalsidase beta is a recombinant enzyme replacement therapy authorized in Europe at a standard dose of 1.0 mg/kg intravenously every other week at an initial infusion rate of ≤ 0.25 mg/min until patient tolerance is established, after which the infusion rate may be increased gradually. However, specific practical guidance regarding the progressive reduction in infusion time is lacking. This study investigated a new and specific protocol for reducing agalsidase beta infusion time in which a stable dosage of 15 mg/h is infused for the first four months, and the infusion rate is increased progressively from 15 to 35 mg/h for the subsequent four infusions. The shortest infusion time is reached after six months and maintained thereafter. The incidence of infusion-associated reactions (IARs) and the development of anti-drug antibodies were analyzed, and the disease burden and the clinical evolution of the disease at 12 months were evaluated. RESULTS: Twenty-five of the 31 patients were naïve to enzyme or chaperone treatment at baseline and six patients had been switched from agalsidase alfa. The reduced infusion time protocol was well tolerated. Only one patient exhibited an IAR, with mild symptoms that resolved with low-dose steroids. Six patients globally seroconverted during treatment (4 with a classic phenotype and 2 with late-onset disease). All but three patients were seronegative at month 12. All patients were stable at the study's end (FAbry STabilization indEX value < 20%); reducing infusion time did not negatively impact clinical outcomes in any patient. The perceived medical assessment showed that the quality of life of all patients improved. CONCLUSIONS: The study demonstrates that reducing agalsidase beta infusion time is possible and safe from both an immunogenic and clinical point of view. The use of a low infusion rate in the first months when the probability of onset of the development of antibodies is higher contributed to very limited seroconversion to antibody-positive status.

Alemtuzumab infusion-associated reactions and laboratory changes in patients with relapsing-remitting multiple sclerosis at baseline and first-year follow-up.

Background: Alemtuzumab (ATZ) is an anti-CD52 humanized monoclonal antibody indicated for treating highly active relapsing-remitting MS (RRMS). It alters the regulation of the immune system by depleting circulating lymphocytes. Changes in blood cell count, infusion-related reactions, and changes in vital parameters can be seen in the early period with ATZ. Aim: Changes in blood tests, serum tests, vital parameters, and characteristics of infusion-associated reactions (IARs) observed during the first course of ATZ treatment and thereafter were evaluated. Materials and methods: The systolic blood pressure (SBP), diastolic blood pressure (DBP), fever, heart rate (HR), changes in blood and serum tests, and IARs developed after the first course of 23 patients with RRMS who received ATZ treatment were evaluated by comparing the results of 26 patients with RRMS who received only intravenous methylprednisolone. Results: Mean age was 36.60 ± 8.98, 73.9% female (n = 17), diagnosis time was 8.52 ± 3.64 years, pre-EDSS: 3.93 ± 1.80. No significant difference was found in vital parameters except for sub-febrile fever that developed on the first day. The number of white blood cells increased significantly after the first day. The hemoglobin level did not change. Lymphocyte (very high) and platelet (mild) counts decreased starting from the first days, and eosinophil (very high) and monocyte (moderate) counts decreased from the third day. There were no significant changes in liver enzymes, thyroid function tests, serum urea, creatinine, and lipid profile during 1-year follow-up. The IAR rate was 95.6% and occurred most frequently on the second and third days. The most common are dermatological findings (52%), headache (20%), pain (10%) and fatigue (8%). Conclusion: Alemtuzumab has no appreciable effect on vital parameters during infusion. However, these changes are not clinically correlated, even if there is. Headache in the first days, dermatological (most common) findings, pain, and fatigue are seen in the following days. Most IARs can be resolved with symptomatic treatment and close follow-up. Lymphocytes, eosinophils, and monocytes are significantly reduced and return to baseline levels towards the end of the first year. The first year does not cause significant pathologies in other serum parameters. However, after the first year, watch out for associated autoimmune pathologies, especially thyroid involvement.

Home-based enzyme replacement therapy in children and adults with Pompe disease; a prospective study.

BACKGROUND: Pompe disease is a lysosomal storage disease treated with life-long enzyme replacement therapy (ERT). Home-based ERT has been provided in the Netherlands since 2008 because it diminishes the burden of treatment, increases patient flexibility and autonomy, and is thus a more patient-centred approach to ERT. METHODS: All Dutch Pompe patients receiving alglucosidase alfa infusions at home were approached to participate in a questionnaire to validate the safety of home-based ERT. Prospective data on symptoms occurring during or within 48 h after infusion and retrospective data on infusion associated reactions (IARs) in the last three months were collected four times during one year. RESULTS: In total, 116 out of 120 eligible patients (17 classic infantile, 2 atypical infantile, 15 childhood onset and 82 adult) filled out 423 questionnaires (response rate: 88.1%). Symptoms during or after infusion were reported 27 times in 17 patients. Fatigue was the most commonly reported health complaint (in 9.5% of patients). Four health complaints were judged to be IARs and reported to the Erasmus MC University Medical Center. None of the IARs reported in this study warranted emergency clinical care. CONCLUSIONS: Our data demonstrate that home-based ERT in Pompe disease can be safely implemented as few, mostly mild, symptoms were reported during or after infusion. Insights from this study can be used as a base for implementing home-based ERT in other countries and to further optimize patient care, as unreported mild symptoms do not pose a health risk but may still be relevant to the patient.

A national, multi-center study in Germany to assess implementation of infusion management, treatment satisfaction and quality of life in MS patients receiving alemtuzumab.

BACKGROUND: Alemtuzumab is an anti-CD52 antibody approved for the treatment of relapsing remitting multiple sclerosis (RRMS). The summary of product characteristics (SmPC) provides recommendations on the administration of alemtuzumab to prevent or reduce the risk of serious side effects associated with alemtuzumab infusion, including myocardial ischemia, hemorrhagic stroke, arterial dissection, and pulmonary alveolar hemorrhage. However, real-world implementation of alemtuzumab infusion management recommendations has not been previously assessed. METHODS: Here we provide a large-scale multi-center (in- and outpatient) observational study on alemtuzumab infusion management in daily clinical care in Germany (ALEMLL08025; INFUSE-MS; NIS-no. 364). Parameters of infusion management - including infusion administration, clinical and laboratory monitoring - were assessed, compared between study centers and the occurrence of infusion-associated reactions (IARs) was documented. Moreover, the TSQM and MSIS-29 questionnaires were used to quantify patient satisfaction and health-related quality of life. RESULTS: 140 RRMS patients were enrolled in this study. Alemtuzumab infusion regimes (treatment course 1 and 2) were comparable between infusion sites and in accordance with recommendations by the SmPC. Standardization of infusion management was associated with a satisfactory safety profile. IARs were usually mild, headache (13.6%), rash (10.7%), and pyrexia (6.4%) being the most common ones. TSQM and MSIS-29 scores denoted high patient satisfaction and health-related quality of life among RRMS patients treated with alemtuzumab. CONCLUSION: In conclusion, our results indicate that infusion management of alemtuzumab is highly standardized and in line with the SmPC. Alemtuzumab treatment and implementation of infusion management recommendations are associated with a satisfactory safety profile regarding the occurrence of IARs, a high patient satisfaction and health-related quality of life as important indicators for the quality of MS care.

Immune responses to alglucosidase in infantile Pompe disease: recommendations from an Italian pediatric expert panel.

BACKGROUND: Classic infantile onset of Pompe disease (c-IOPD) leads to hypotonia and hypertrophic cardiomyopathy within the first days to weeks of life and, without treatment, patients die of cardiorespiratory failure in their first 1-2 years of life. Enzymatic replacement therapy (ERT) with alglucosidase alfa is the only available treatment, but adverse immune reactions can reduce ERT's effectiveness and safety. It is therefore very important to identify strategies to prevent and manage these complications. Several articles have been written on this disease over the last 10 years, but no univocal indications have been established. METHODS: Our study presents a review of the current literature on management of immune responses to ERT in c-IOPD as considered by an Italian study group of pediatric metabolists and immunologists in light of our shared patient experience. RESULTS: We summarize the protocols for the management of adverse reactions to ERT, analyzing their advantages and disadvantages, and provide expert recommendations for their optimal management, to the best of current knowledge. However, further studies are needed to improve actual management protocols, which still have several limitations.

A new strategy of desensitization in mucopolysaccharidosis type II disease treated with idursulfase therapy: A case report and review of the literature.

Mucopolysaccharidosis type II (MPS II) is a multisystemic lysosomal storage disorder caused by deficiency of the iduronate 2-sulfatase enzyme. Currently, enzyme replacement therapy (ERT) with recombinant idursulfase is the main treatment available to decrease morbidity and improve quality of life. However, infusion-associated reactions (IARs) are reported and may limit access to treatment. When premedication or infusion rate reductions are ineffective for preventing IARs, desensitization can be applied. To date, only two MPS II patients are reported to have undergone desensitization. We report a pediatric patient with recurrent IARs during infusion successfully managed with gradual desensitization. Our protocol started at 50% of the standard dosage infused at concentrations from 0.0006 to 0.06 mg/ml on weeks 1 and 2, followed by 75% of the standard dosage infused at concentrations from 0.0009 to 0.09 mg/ml on weeks 3 and 4, and full standard dosage thereafter, infused at progressively increasing concentrations until the standard infusion conditions were reached at 3 months. Our experience can be used in the management of MPS II patients presenting IARs to idursulfase infusion, even when general preventive measures are already administered.

Stepwise shortening of agalsidase beta infusion duration in Fabry disease: Clinical experience with infusion rate escalation protocol.

BACKGROUND: Although enzyme replacement therapy with agalsidase beta resulted in a variety of clinical benefits, life-long biweekly intravenous infusion may impact on patients' quality of life. Moreover, regular infusions are time-consuming: although a stepwise shortening of infusion duration is allowed up to a minimum of 1.5 hr, in most centers it remains ≥3 hr, and no data exists about the safety and tolerability of agalsidase beta administration at maximum tolerated infusion rate. METHODS: In this study, we reported our experience with a stepwise infusion rate escalation protocol developed in our center in a cohort of 53 Fabry patients (both already receiving and treatment-naΪve), and explored factors predictive for the infusion rate increase tolerability. RESULTS: Fifty-two patients (98%) reduced infusion duration ≤3 hr; of these, 38 (72%) even reached a duration ≤2 hr. We found a significant difference between the mean duration reached by already treated and naΪve patients (p < .01). More severely affected patients (male patients and those with lower enzyme activity) received longer infusions for higher risk of infusion-associated reactions (IARs). A significant correlation between anti-agalsidase antibodies and IARs was found. CONCLUSION: Our infusion rate escalation protocol is safe and could improve patient compliance, satisfaction and quality of life.

Management of infusion related reactions associated with alemtuzumab in patients with multiple sclerosis.

OBJECTIVE: Infusion-associated reactions (IARs) occur in >90% patients with multiple sclerosis (MS) treated with alemtuzumab. We aimed to study the frequency of IARs at 2 sites using 5 days of steroids (1g/day of IV methylprednisolone), but otherwise distinct protocols. METHODS: This was retrospective chart review of 38 consecutive MS patients who were treated with alemtuzumab from June 2015 till February 2017 at Department of Neurology, University Hospital Center Zagreb, Croatia and Department of Neurology, University Medical Center Ljubljana, Slovenia. RESULTS: Seventeen patients (44.7%) did not experience IARs. Skin reactions and fever were the most common IARs attributed to alemtuzumab infusions and they were most frequent on Day 5 and Day 1, respectively. We have observed significant differences in the occurrence of fever (p = 0.005) depending on the site of alemtuzumab administration which could be explained by different antipyretics used; fever was absent in the Slovenian cohort because high dose intravenous metamizole was administered. Two out of 9 treatment naïve, and 19 out of 29 patients who previously received immunomodulatory treatment had IARs (χ2 = 5.208, p = 0.022). CONCLUSION: Modified premedication scheme consisting of 1g/day of IV methylprednisolone throughout all 5 days of alemtuzumab treatment may reduce overall IARs. Intravenous administration of antipyretics may work better than oral administration.