Long-term Immunogenicity of Elosulfase Alfa in the Treatment of Morquio A Syndrome: Results From MOR-005, a Phase III Extension Study.

PURPOSE: Elosulfase alfa is an enzyme replacement therapy for the treatment of Morquio A syndrome (mucopolysaccharidosis IVA), a lysosomal storage disorder caused by a deficiency of the enzyme N-acetylgalactose-amine-6-sulfatase. We previously reported immunogenicity data from our 24-week placebo-controlled Phase III study, MOR-004. Here, we report the long-term immunogenicity profile of elosulfase alfa from MOR-005, the Phase III extension trial to assess potential correlations between antidrug antibodies and efficacy and safety profile outcomes throughout 120 weeks of treatment. METHODS: The long-term immunogenicity of elosulfase alfa was evaluated in patients with Morquio A syndrome in an open-label extension study for a total of 120 weeks. All patients received 2.0 mg/kg elosulfase alfa either weekly or every other week before establishment of 2.0 mg/kg/wk as the recommended dose, at which time all patients received weekly treatment. Efficacy measures were compared with those from the MOR-004 baseline, enabling analysis of changes over 120 weeks. The primary efficacy measure was the change from baseline in 6-minute walk test. Secondary measures included changes from baseline in 3-minute stair climb test and normalized urine keratan sulfate, a pharmacodynamic metric. FINDINGS: All patients treated with elosulfase alfa developed antidrug total antibodies (TAb) by week 24 of MOR-004. In the extension study, all patients, including those who had previously received placebo, were TAb positive by study week 36 (MOR-005 week 12). All patients remained TAb positive throughout the study, and TAb titers were similar across treatment groups at week 120. Nearly all patients tested positive for neutralizing antibodies (NAb) at least once, with incidence of NAb positivity peaking at 85.9% at study week 36, then steadily declining to 66.0% at study week 120. In all treatment groups, mean urine keratan sulfate remained below treatment-naive baseline despite the presence of antidrug antibodies. No relationship was observed between TAb titers or NAb positivity and changes in urine keratan sulfate, 6-minute walk test, or 3-minute stair climb test from baseline to week 120. No consistent associations were detected between antidrug antibodies and the occurrence of hypersensitivity adverse events or anaphylaxis over the course of the study. IMPLICATIONS: Immunogenicity results from this long-term study are consistent with previously reported 24-week results. Despite the sustained presence of antidrug antibodies, elosulfase alfa was well tolerated, and patients continued to benefit from treatment through week 120. No associations were detected between higher TAb titers or NAb positivity and reduced treatment effect or worsened safety profile measures. ClinicalTrials.gov identifier: NCT01415427.

Antibodies that neutralize cellular uptake of elosulfase alfa are not associated with reduced efficacy or pharmacodynamic effect in individuals with Morquio A syndrome.

Many enzyme replacement therapies (ERTs) for lysosomal storage disorders use the cell-surface cation-independent mannose-6 phosphate receptor (CI-M6PR) to deliver ERTs to the lysosome. However, neutralizing antibodies (NAb) may interfere with this process. We previously reported that most individuals with Morquio A who received elosulfase alfa in the phase 3 MOR-004 trial tested positive for NAbs capable of interfering with binding to CI-M6PR ectodomain in an ELISA-based assay. However, no correlation was detected between NAb occurrence and clinical efficacy or pharmacodynamics. To quantify and better characterize the impact of NAbs, we developed a functional cell-based flow cytometry assay with a titer step that detects antibodies capable of interfering with elosulfase alfa uptake. Serum samples collected during the MOR-004 trial were tested and titers were determined. Consistent with earlier findings on NAb positivity, no correlations were observed between NAb titers and the clinical outcomes of elosulfase alfa-treated individuals with Morquio A.

Pharmacodynamics, pharmacokinetics and biodistribution of recombinant human N-acetylgalactosamine 4-sulfatase after 6months of therapy in cats using different IV infusion durations.

BACKGROUND: Mucopolysaccharidosis VI (MPS VI) is a lysosomal storage disease characterized by an absence or marked reduction of lysosomal N-acetylgalactosamine-4-sulfatase activity. Affected individuals have widespread accumulation of unmetabolized glycosaminoglycan substrates leading to detrimental effects. Recombinant human N-acetylgalactosamine 4-sulfatase (rhASB) is an approved enzyme replacement therapy for patients with MPS VI. Despite the known efficacy of weekly 4-h rhASB infusions, some clinicians wish to treat patients using reduced infusion times. This study compared the pharmacodynamics, pharmacokinetics, and tissue biodistribution of rhASB when administered as 2- and 4-h intravenous infusions using a feline model of MPS VI. METHODS: Study animals were MPS VI-affected cats that demonstrate clinical signs and biochemical derangements similar to human MPS VI patients. Beginning at age 4weeks, animals received weekly 2-h (N=6) or 4-h (N=6) IV infusions of rhASB for 26weeks (Naglazyme® [galsulfase] Solution for Intravenous Infusion; BioMarin Pharmaceutical, Inc.). The control group consisted of untreated MPS VI-affected cats (N=6). The pharmacokinetic parameters of plasma rhASB and urinary glycosaminoglycan were determined at weeks 13 and 26. Animals were euthanized 48h after the last infusion and tissue concentration of ASB, GAG and ß-glucuronidase were measured in the liver, spleen, aorta, and kidney. Skeletal and ophthalmological evaluations were performed within 2weeks of euthanasia. RESULTS: At week 13, the mean AUC0-t in animals treated with 4-h infusions was similar to 2-h infusions while the Cmax of the 4-h infusion was 50% of the 2-h infusion. By week 26, the mean AUC0-t of the 4-h infusion was 1.3-fold higher than the 2-h infusion (p<0.05) while Cmax of the 4-h infusion was 70% of the 2-h infusion (p<0.05). Among animals treated with 2- and 4-h infusions, there was no difference in urinary GAG excretion, tissue GAG storage, tissue galsulfase activity, and ß-glucuronidase but all were significantly different than control animals (for each, p<0.001). Radiographic skeletal abnormality scores for animals were also similar for both treatment groups and significantly higher than control animals (p<0.001). There was no significant difference in corneal clouding scores among treated and untreated animals. CONCLUSIONS: There was no significant difference in clinical outcomes when rhASB was administered to MPS VI affected cats as 2- and 4-h infusions over 26weeks. Additional studies may determine if shorter infusion times are appropriate for MPS VI patients without significant infusion-associated reactions.

Immunogenicity of Elosulfase Alfa, an Enzyme Replacement Therapy in Patients With Morquio A Syndrome: Results From MOR-004, a Phase III Trial.

PURPOSE: Morquio A syndrome (mucopolysaccharidosis IVA [MPS IVA]) is a lysosomal storage disorder caused by deficiency of the enzyme N-acetylgalactosamine-6-sulfatase, which is required to degrade the glycosaminoglycan keratan sulfate. Morquio A is associated with extensive morbidity and early mortality. Elosulfase alfa is an enzyme replacement therapy that provides a treatment option for patients with Morquio A. We examined the immunogenicity profile of elosulfase alfa, assessing any correlations between antidrug antibodies and the efficacy and safety outcomes in 176 patients with Morquio A from a 24-week international Phase III trial. METHODS: Patients were randomized to placebo (n = 59) or elosulfase alfa 2.0 mg/kg administered weekly (n = 58) or every other week (n = 59) as an ~4-hour infusion. Blood samples were routinely tested to determine drug-specific total antibody titer and neutralizing antibody (NAb) positivity. Drug-specific immunoglobulin E positivity was tested routinely and in response to severe hypersensitivity adverse events (AEs). Antidrug antibody positivity and titer were compared with efficacy and safety metrics to assess possible correlations. FINDINGS: The 176 patients in the trial were 54% female, with a mean age of 11.9 years. In all patients treated with elosulfase alfa antidrug antibodies developed, and in the majority, antibodies capable of interfering with cation-independent mannose-6-phosphate receptor binding in vitro (NAb) developed. Less than 10% of patients tested positive for drug-specific IgE during the study. Despite the high incidence of anti-elosulfase alfa antibodies, no correlations were detected between higher total antibody titers or NAb positivity and worsened 6-minute walk test results, urine keratin sulfate levels, or hypersensitivity AEs. Drug-specific IgE positivity had no apparent association with the occurrence of anaphylaxis, other hypersensitivity AEs, and/or treatment withdrawal. IMPLICATIONS: Despite the universal development of antidrug antibodies, elosulfase alfa treatment was both safe and well tolerated and immunogenicity was not associated with reduced treatment effect. ClinicalTrials.gov identifier: NCT01275066. (Clin Ther.

Pharmacokinetic and pharmacodynamic evaluation of elosulfase alfa, an enzyme replacement therapy in patients with Morquio A syndrome.

BACKGROUND AND OBJECTIVES: Morquio A syndrome (mucopolysaccharidosis IVA; MPS IVA) is a lysosomal storage disorder caused by deficiency of N-acetylgalactosamine-6-sulfatase, an enzyme required for degradation of the glycosaminoglycan keratan sulfate. Enzyme replacement therapy with elosulfase alfa provides a potential therapy for Morquio A syndrome. We analyzed the pharmacokinetics and pharmacodynamics of elosulfase alfa in Morquio A patients from a phase III clinical trial. METHODS: In a randomized double-blind study, elosulfase alfa at 2.0 mg/kg was administrated weekly or every other week for 24 weeks. Pharmacokinetic parameters of elosulfase alfa were determined at weeks 0 and 22 by non-compartmental analysis. Safety was assessed throughout the study. The relationship of pharmacokinetic parameters to patient demographics, pharmacodynamic assessments, immunogenicity, and efficacy and safety outcomes were assessed graphically by treatment group. RESULTS: Elosulfase alfa exposure and half-life (t(½)) increased for both dose regimens during the study. There appeared to be no consistent trend between drug clearance (CL) and patient's sex, race, body weight, or age. All patients developed anti-drug antibodies, but no association was noted between total antibody titer and CL. In contrast, positive neutralizing antibody (NAb) status appeared to associate with decreased CL and prolonged t(½) for patients in the cohort dosed weekly. NAb may interfere with receptor-mediated cellular uptake and lead to increased circulation time of elosulfase alfa. CONCLUSION: Despite the association between NAb and decreased drug clearance, neither dosing cohort showed associations between drug exposure and change in urinary keratan sulfate, 6-min walk test distances, or the occurrence of adverse events.

Asymptomatic reactivation of JC virus in patients treated with natalizumab.

BACKGROUND: Progressive multifocal leukoencephalopathy (PML) occurs in a fraction of patients with multiple sclerosis who were treated with natalizumab. Most adults who are infected with the JC virus, the etiologic agent in PML, do not have symptoms. We sought to determine whether exposure to natalizumab causes subclinical reactivation and neurotropic transformation of JC virus. METHODS: We followed 19 consecutive patients with multiple sclerosis who were treated with natalizumab over an 18-month period, performing quantitative polymerase-chain-reaction assays in blood and urine for JC virus reactivation; BK virus, a JC virus-related polyomavirus, was used as a control. We determined JC virus-specific T-cell responses by means of an enzyme-linked immunospot assay and antibody responses by means of an enzyme-linked immunosorbent assay and analyzed JC virus regulatory-region sequences. RESULTS: After 12 months of natalizumab therapy, the prevalence of JC virus in the urine of the 19 patients increased from a baseline value of 19% to 63% (P=0.02). After 18 months of treatment, JC virus was detectable in 3 of 15 available plasma samples (20%) and in 9 of 15 available samples of peripheral-blood mononuclear cells (60%) (P=0.02). JC virus regulatory-region sequences in blood samples and in most of the urine samples were similar to those usually found in PML. Conversely, BK virus remained stable in urine and was undetectable in blood. The JC virus-specific cellular immune response dropped significantly between 6 and 12 months of treatment, and variations in the cellular immune response over time tended to be greater in patients in whom JC viremia developed. None of the patients had clinical or radiologic signs of PML. CONCLUSIONS: Subclinical reactivation of JC virus occurs frequently in natalizumab-treated patients with multiple sclerosis. Viral shedding is associated with a transient drop in the JC virus-specific cellular immune response.

Efficient in vitro expansion of JC virus-specific CD8(+) T-cell responses by JCV peptide-stimulated dendritic cells from patients with progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the brain caused by JC virus (JCV) for which there is no cure. PML patients who have JCV-specific CD8(+) cytotoxic T lymphocytes (CTL) in their blood have a better clinical outcome. We compared JCV-specific CTL responses in vitro elicited either by JCV peptide-loaded dendritic cells (DC) or by direct peptide stimulation of lymphocytes from 20 HLA-A0201(+) healthy controls, HIV(+) and PML patients. JCV peptide-loaded DC elicited a stronger CTL expansion in 13/15 responders. DC can induce a potent JCV-specific CTL response in vitro, and may constitute a promising approach for PML immunotherapy.

Rearrangement of the JC virus regulatory region sequence in the bone marrow of a patient with rheumatoid arthritis and progressive multifocal leukoencephalopathy.

The polyomavirus JC (JCV) is the etiologic agent of progressive multifocal leukoencephalopathy (PML). JCV remains quiescent in kidneys, where it displays a stable archetypal regulatory region (RR). Conversely, rearranged JCV RR, including tandem repeat patterns found in the central nervous system (CNS) of PML patients, have been associated with neurovirulence. The precise site and mechanism of JCV RR transformation is unknown. We present herein a patient with rheumatoid arthritis treated with methotrexate, who developed PML and had a rapid fatal outcome. JCV DNA polymerase chain reaction (PCR) was positive in cerebrospinal fluid (CSF), bone marrow, blood, and urine. Double-immunohistochemical staining demonstrated that 9% of bone marrow CD138(+) plasma cells sustained productive infection by JCV, accounting for 94% of JCV-infected cells. JCV RR analysis revealed archetype and rearranged RR forms in bone marrow, whereas RR with tandem repeat was predominant in blood. These results suggest that the bone marrow may be a potential site of JCV pathogenic transformation. Further studies will be needed to determine the prevalence of JCV in bone marrow of immunosuppressed individuals at risk of PML and characterize the RR and phenotype of these JCV isolates.

Frequency and phenotype of JC virus-specific CD8+ T lymphocytes in the peripheral blood of patients with progressive multifocal leukoencephalopathy.

JC virus (JCV)-specific CD8+ cytotoxic T lymphocytes (CTL) are associated with a favorable outcome in patients with progressive multifocal leukoencephalopathy (PML) and cross-recognize the polyomavirus BK virus (BKV). We sought to determine the frequency and phenotype in fresh blood of CD8+ T cells specific for two A*0201-restricted JCV epitopes, VP1(p36) and VP1(p100), and assess their impact on JC and BK viremia and viruria in 15 healthy subjects, eight human immunodeficiency virus-positive (HIV+) individuals, and nine HIV+ patients with PML (HIV+ PML patients) classified as survivors. After magnetic pre-enrichment of CD8+ T cells, epitope-specific cells ranged from 0.001% to 0.022% [corrected] by tetramer staining, with no significant difference among the three study groups. By use of seven-color flow cytometry, there was no predominant differentiation phenotype subset among JCV-specific CD8+ T cells in healthy individuals, HIV+ subjects, or HIV+ PML patients. However, in one HIV+ PML patient studied in the acute phase, there was a majority of activated effector memory cells. BKV DNA was undetectable in all blood samples by quantitative PCR, while a low JC viral load was found in the blood of only one HIV+ and two HIV+ PML patients. JCV and BKV DNA were detected in 33.3% and 13.3% of all urine samples, respectively, independent of the presence of JCV-specific CTL. The detection of JCV DNA in the urine was associated with the presence of a JCV VP1(p100) CTL response. Immunotherapies aiming at increasing the cellular immune response against JCV may be valuable in the treatment of HIV+ individuals with PML.