Immune response to enzyme replacement therapies in lysosomal storage diseases and the role of immune tolerance induction

Cell based assay identifies TLR2 and TLR4 stimulating impurities in Interferon beta

Immunogenicity can have devastating consequences on the safety and efficacy of therapeutic proteins. Therefore, evaluating and mitigating the risk of product immunogenicity is critical for the development these products. This study, showed that Betaseron and Extavia, which are reported to be more immunogenic among IFNβ products in clinical usage, contain residual innate immune response modulating impurities (IIRMIs) capable of activating NF-κB and induced expression of inflammatory mediators. These IIRMIs were undetectable in Rebif or Avonex. The stimulatory effect was attributed solely to IIRMIs because it was evident in murine cells lacking the interferon receptor (IFNAR). The IIRMIs in Betaseron and Extavia triggered NF-κB activation in HEK-293 cells bearing TLR2 and TLR4 in MyD88 dependent manner. Importantly, the IIRMIs in Betaseron induced up-regulation of IL-6, IL-1β, and ccl5 in the skin of IFNAR knock out mice following subcutaneous administration. This indicates that trace level IIRMIs in Betaseron could contribute to the higher immunogenicity rates seen in clinics. Together these data suggest that cell based assays can reveal subtle but clinically relevant differences in IIRMIs following manufacturing changes or between products with the same active ingredients but different manufacturing processes. Appreciating these differences may inform immunogenicity risk assessments.

Correlation between urinary GAG and anti-idursulfase ERT neutralizing antibodies during treatment with NICIT immune tolerance regimen: A case report

INTRODUCTION

Antibodies to intravenous idursulfase enzyme replacement therapy (ERT) for patients with Hunter syndrome (mucopolysaccharidosis type II, MPS II) can have a harmful clinical impact, including both increasing risk of infusion reactions and inhibiting therapeutic activity. Thus, failure to monitor anti-idursulfase antibodies and neutralizing antibodies, and delays in reporting results, may postpone critical clinical decisions.

HYPOTHESIS

Urinary glycosaminoglycan (GAG) levels may be used as a biomarker for anti-idursulfase antibodies and neutralizing antibodies to improve timeliness in monitoring and managing ERT.

METHODS

This is a case report describing a patient with MPS II with high levels of neutralizing antibodies and worsened clinical status who was treated for five years with a non-immunosuppressive and non-cytotoxic immune tolerance (NICIT) regimen, consisting of intravenous immune globulin and frequent infusions of idursulfase. Neutralizing antibodies and total anti-idursulfase antibodies were measured by two different methods, the direct 1,9-dimethylmethylene blue (DMB) assay and cetylpyridinium chloride carbazole-borate (CPC) assay.

RESULTS

Neutralizing antibodies, measured as percent inhibition of enzyme activity and also by total neutralizing antibody titer, were correlated with quantitative urinary GAG measured by DMB assay (p=0.026, p=0.0067), and quantitative urinary GAG by CPC assay with percent inhibition of enzyme activity by neutralizing antibodies (p=0.0475). The NICIT regimen showed a sustained immune tolerance after five years and was well-tolerated.

CONCLUSIONS

Urinary GAG, measured by DMB assay, may be a biomarker for anti-idursulfase neutralizing antibodies and is useful for managing immune tolerance regimens for patients with MPS II who have high levels of anti-idursulfase neutralizing antibodies. This study highlights the importance of regular and frequent monitoring of urinary GAG in patients with MPS II who are receiving ERT. The NICIT regimen, with less drug toxicities, may be preferred in patients with MPS who have a high risk of infections and whose disease progresses less rapidly than some other lysosomal storage diseases, such as infantile Pompe disease.

Lysosomal enzyme replacement therapies: Historical development, clinical outcomes, and future perspectives

Lysosomes and lysosomal enzymes play a central role in numerous cellular processes, including cellular nutrition, recycling, signaling, defense, and cell death. Genetic deficiencies of lysosomal components, most commonly enzymes, are known as "lysosomal storage disorders" or "lysosomal diseases" (LDs) and lead to lysosomal dysfunction. LDs broadly affect peripheral organs and the central nervous system (CNS), debilitating patients and frequently causing fatality. Among other approaches, enzyme replacement therapy (ERT) has advanced to the clinic and represents a beneficial strategy for 8 out of the 50-60 known LDs. However, despite its value, current ERT suffers from several shortcomings, including various side effects, development of "resistance", and suboptimal delivery throughout the body, particularly to the CNS, lowering the therapeutic outcome and precluding the use of this strategy for a majority of LDs. This review offers an overview of the biomedical causes of LDs, their socio-medical relevance, treatment modalities and caveats, experimental alternatives, and future treatment perspectives.

Sustained immune tolerance induction in enzyme replacement therapy-treated CRIM-negative patients with infantile Pompe disease

BACKGROUND

Cross-reactive immunological material-negative (CRIM-negative) infantile Pompe disease (IPD) patients develop an immune response against enzyme replacement therapy (ERT) with alglucosidase alfa that nullifies ERT efficacy. Prophylactic immune tolerance induction (ITI) with rituximab, methotrexate, and IVIG successfully prevents development of deleterious rhGAA IgG antibodies; however, safety, likelihood of success, and long-term efficacy of ITI in a larger cohort remain unknown.

METHODS

Clinical data were analyzed for 19 CRIM-negative IPD patients who received ITI with rituximab, methotrexate, and IVIG in the ERT-naive setting (ERT+ITI) and compared to a historical cohort of 10 CRIM-negative IPD patients on ERT monotherapy.

RESULTS

ITI was safely tolerated, although infections were reported in 4 patients. Fourteen (74%) ERT+ITI patients were alive, with a median age of 44.2 months at their final assessment. The eldest survivor was 103.9 months old, with 100.2 months of follow-up after initiation of ERT+ITI. Death (n = 5) occurred at a median age of 29.2 months and was unrelated to the administration of ITI. Fifteen patients either did not seroconvert (n = 8) or maintained low titers (n = 7; defined as titers of ≤6,400 throughout the course of ERT) following ERT+ITI. Only one patient developed high and sustained antibody titers (defined as titers of ≥51,200 at or beyond 6 months on ERT). Left ventricular mass index (LVMI) decreased from a median of 248.5 g/m2 at baseline to 76.8 g/m2 at a median time from ERT+ITI initiation to 59 weeks. ERT+ITI significantly improved overall survival (P = 0.001), eliminated/reduced antibodies at values of ≤6,400 at week 52 on ERT (P = 0.0004), and improved LVMI at week 52 on ERT (P = 0.02) when compared with ERT monotherapy.

CONCLUSION

Evidence from this international cohort of CRIM-negative IPD patients further supports the safety, feasibility, and efficacy of ITI in the prevention of immune responses to ERT.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01665326.

FUNDING

This research was supported in part by the Lysosomal Disease Network, a part of NIH Rare Diseases Clinical Research Network, and by a grant from Genzyme, a Sanofi company.

Management of Confirmed Newborn-Screened Patients With Pompe Disease Across the Disease Spectrum

After a Pompe disease diagnosis is confirmed in infants identified through newborn screening (NBS), when and if to start treatment with enzyme replacement therapy (ERT) with alglucosidase alfa must be determined. In classic infantile-onset Pompe disease, ERT should start as soon as possible. Once started, regular, routine follow-up is necessary to monitor for treatment effects, disease progression, and adverse effects. Decision-making for when or if to start ERT in late-onset Pompe disease (LOPD) is more challenging because patients typically have no measurable signs or symptoms or predictable time of symptom onset at NBS. With LOPD, adequate, ongoing follow-up and assessments for onset or progression of signs and symptoms are important to track disease state and monitor and adjust care before and after treatment is started. Because numerous tests are used to monitor patients at variable frequencies, a standardized approach across centers is lacking. Significant variability in patient assessments may result in missed opportunities for early intervention. Management of Pompe disease requires a comprehensive, multidisciplinary approach with timely disease-specific interventions that target the underlying disease process and symptom-specific manifestations. Regardless of how identified, all patients who have signs or symptoms of the disease require coordinated medical care and follow-up tailored to individual needs throughout their lives. The Pompe Disease Newborn Screening Working Group identifies key considerations before starting and during ERT; summarizes what comprises an indication to start ERT; and provides guidance on how to determine appropriate patient management and monitoring and guide the frequency and type of follow-up assessments for all patients identified through NBS.

Red blood cells: Supercarriers for drugs, biologicals, and nanoparticles and inspiration for advanced delivery systems

Red blood cells (RBCs) constitute a unique drug delivery system as a biologic or hybrid carrier capable of greatly enhancing pharmacokinetics, altering pharmacodynamics (for example, by changing margination within the intravascular space), and modulating immune responses to appended cargoes. Strategies for RBC drug delivery systems include internal and surface loading, and the latter can be performed both ex vivo and in vivo. A relatively new avenue for RBC drug delivery is their application as a carrier for nanoparticles. Efforts are also being made to incorporate features of RBCs in nanocarriers to mimic their most useful aspects, such as long circulation and stealth features. RBCs have also recently been explored as carriers for the delivery of antigens for modulation of immune response. Therefore, RBC-based drug delivery systems represent supercarriers for a diverse array of biomedical interventions, and this is reflected by several industrial and academic efforts that are poised to enter the clinical realm.

Long-term exposure to Myozyme results in a decrease of anti-drug antibodies in late-onset Pompe disease patients

Immunogenicity of recombinant human acid-alpha glucosidase (rhGAA) in enzyme replacement therapy (ERT) is a safety and efficacy concern in the management of late-onset Pompe disease (LOPD). However, long-term effects of ERT on humoral and cellular responses to rhGAA are still poorly understood. To better understand the impact of immunogenicity of rhGAA on the efficacy of ERT, clinical data and blood samples from LOPD patients undergoing ERT for >4 years (n = 28) or untreated (n = 10) were collected and analyzed. In treated LOPD patients, anti-rhGAA antibodies peaked within the first 1000 days of ERT, while long-term exposure to rhGAA resulted in clearance of antibodies with residual production of non-neutralizing IgG. Analysis of  T cell responses to rhGAA showed detectable T cell reactivity only after in vitro restimulation. Upregulation of several cytokines and chemokines was detectable in both treated and untreated LOPD subjects, while IL2 secretion was detectable only in subjects who received ERT. These results indicate that long-term ERT in LOPD patients results in a decrease in antibody titers and residual production of non-inhibitory IgGs. Immune responses to GAA following long-term ERT do not seem to affect efficacy of ERT and are consistent with an immunomodulatory effect possibly mediated by regulatory T cells.

Delayed Infusion Reactions to Enzyme Replacement Therapies

BACKGROUND

There are currently ten intravenous enzyme replacement therapy (ERT) products available for the treatment of eight different lysosomal diseases (LD) in the USA. Additional ERT products are in clinical trials. The most common ERT adverse events are infusion reactions (IR). While IR are often defined as hypersensitivity or anaphylactoid reactions occurring concurrently with (i.e., during) infusion administration (CIR), there exists the potential for delayed infusion reactions (DIR), which present after completion of infusion administration.

HYPOTHESIS

Concurrent infusion reactions (CIR) are not the only infusion reactions associated with enzyme therapy.

METHODS

This study evaluated the occurrence of infusion reactions in 46 patients with LD who had received ERT for a minimum of 2 years. Infusion reactions were evaluated according to symptoms, time of onset, and duration of reactions. The frequency of infusion reactions with each ERT product was compared to that reported in the FDA-approved product package insert.

RESULTS AND CONCLUSIONS

In this study, DIR were observed and occurred as often as CIR in the study population, despite not being characterized or reported in most ERT product package inserts. Effective methods for managing DIR and CIR differed, thus emphasizing the importance of monitoring for both types of infusion reactions in order to optimize outcomes for patients using ERT.

The impact of the immune system on the safety and efficiency of enzyme replacement therapy in lysosomal storage disorders

In the light of clinical experience in infantile onset Pompe patients, the immunological impact on the tolerability and long-term efficacy of enzyme replacement therapy (ERT) for lysosomal storage disorders has come under renewed scrutiny. This article details the currently proposed immunological mechanisms involved in the development of anti-drug antibodies and the current therapies used in their treatment. Given the current understanding of the adaptive immune response, it focuses particularly on T cell dependent mechanisms and the paradigm of using lymphocytic negative selection as a predictor of antibody formation. This concept originally postulated in the 1970s, stipulated that the genotypically determined lack of production or production of a variant protein determines an individual's lymphocytic repertoire. This in turn is the key factor in determining the potential severity of an individual's immunological response to ERT. It also highlights the need for immunological assay standardization particularly those looking at describing the degree of functional impact, robust biochemical or clinical endpoints and detailed patient subgroup identification if the true evaluations of impact are to be realised.

Disease models for the development of therapies for lysosomal storage diseases

Lysosomal storage diseases (LSDs) are a group of rare diseases in which the function of the lysosome is disrupted by the accumulation of macromolecules. The complexity underlying the pathogenesis of LSDs and the small, often pediatric, population of patients make the development of therapies for these diseases challenging. Current treatments are only available for a small subset of LSDs and have not been effective at treating neurological symptoms. Disease-relevant cellular and animal models with high clinical predictability are critical for the discovery and development of new treatments for LSDs. In this paper, we review how LSD patient primary cells and induced pluripotent stem cell-derived cellular models are providing novel assay systems in which phenotypes are more similar to those of the human LSD physiology. Furthermore, larger animal disease models are providing additional tools for evaluation of the efficacy of drug candidates. Early predictors of efficacy and better understanding of disease biology can significantly affect the translational process by focusing efforts on those therapies with the higher probability of success, thus decreasing overall time and cost spent in clinical development and increasing the overall positive outcomes in clinical trials.