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Background Imiglucerase (Cerezyme; Sanofi, Paris, France), an analogue of β‐glucocerebrosidase produced by recombinant DNA technology, has been a safe and effective treatment for Gaucher disease (GD) for over 25 years. A new imiglucerase, Abcertin (Seongnam‐si, Gyeonggi‐do, Republic of Korea) has shown a similar safety and efficacy profile in previous clinical studies. This study compared the pharmacokinetics, immunogenicity, safety, and tolerability to EU‐sourced Cerezyme following a single 60 IU/kg dose. Methods This phase 1, single‐center, randomized, double‐blind, two‐way crossover study enrolled 36 healthy volunteers aged 18–45 years. Participants were randomly assigned to receive either Abcertin or Cerezyme in a predetermined sequence. Results Abcertin reached peak plasma concentrations at a median tmax of 61 min (range: 40–121 min). The mean Cmax, AUC0–last, and AUC0–inf were 115.4 mU/mL, 12,190 min·mU/mL, and 12,210 min mU/mL, respectively, indicating bioequivalence to Cerezyme. The mean t½, CL, and Vz were 6.88 min, 376.7 mL/min, and 3.62 L, respectively, and were comparable between the two treatments. One participant in the Cerezyme group developed anti‐drug antibodies, which were non‐neutralizing A total of 24 subjects experienced treatment‐emergent adverse event (TEAE). The most common TEAE was headache (3 in the Abcertin group and 5 in the Cerezyme group), followed by general disorders and administration site condition (3 in Abcertin group and 5 in Cerezyme group). Two participants in the Cerezyme sequence experienced severe TEAEs: one had a urinary tract infection, and the other developed urticaria, which leading to study withdrawal. Conclusion Abcertin demonstrated pharmacokinetic equivalence to Cerezyme, with a comparable safety, immunogenicity, and tolerability profile. These findings support its potential as an affordable biosimilar for GD treatment. This study evaluates the pharmacokinetic equivalence, immunogenicity, and safety profiles of Abcertin and Cerezyme in healthy volunteers. It demonstrated the pharmacokinetic bioequivalence of Abcertin to Cerezyme, highlighted favorable safety and tolerability profiles with no clinically significant adverse events for Abcertin, and confirmed its low immunogenic potential.

Gaucher disease is a progressive lysosomal storage disorder caused by the deficiency of glucocerebrosidase leading to the dysfunction in multiple organ systems. Intravenous enzyme replacement is the accepted standard of treatment. In the current report, we evaluate the safety and pharmacokinetics of a novel human recombinant glucocerebrosidase enzyme expressed in transformed plant cells (prGCD), administered to primates and human subjects. Short term (28 days) and long term (9 months) repeated injections with a standard dose of 60 Units/kg and a high dose of 300 Units/kg were administered to monkeys (n = 4/sex/dose). Neither clinical drug-related adverse effects nor neutralizing antibodies were detected in the animals. In a phase I clinical trial, six healthy volunteers were treated by intravenous infusions with escalating single doses of prGCD. Doses of up to 60 Units/kg were administered at weekly intervals. prGCD infusions were very well tolerated. Anti-prGCD antibodies were not detected. The pharmacokinetic profile of the prGCD revealed a prolonged half-life compared to imiglucerase, the commercial enzyme that is manufactured in a costly mammalian cell system. These studies demonstrate the safety and lack of immunogenicity of prGCD. Following these encouraging results, a pivotal phase III clinical trial for prGCD was FDA approved and is currently ongoing. ClinicalTrials.gov NCT00258778.

Summary For the production of therapeutic proteins in plants, the presence of β1,2‐xylose and core α1,3‐fucose on plants’ N‐glycan structures has been debated for their antigenic activity. In this study, RNA interference (RNAi) technology was used to down‐regulate the endogenous N‐acetylglucosaminyltransferase I (GNTI) expression in Nicotiana benthamiana. One glyco‐engineered line (NbGNTI‐RNAi) showed a strong reduction of plant‐specific N‐glycans, with the result that as much as 90.9% of the total N‐glycans were of high‐mannose type. Therefore, this NbGNTI‐RNAi would be a promising system for the production of therapeutic glycoproteins in plants. The NbGNTI‐RNAi plant was cross‐pollinated with transgenic N. benthamiana expressing human glucocerebrosidase (GC). The recombinant GC, which has been used for enzyme replacement therapy in patients with Gaucher's disease, requires terminal mannose for its therapeutic efficacy. The N‐glycan structures that were presented on all of the four occupied N‐glycosylation sites of recombinant GC in NbGNTI‐RNAi plants (GCgnt1) showed that the majority (ranging from 73.3% up to 85.5%) of the N‐glycans had mannose‐type structures lacking potential immunogenic β1,2‐xylose and α1,3‐fucose epitopes. Moreover, GCgnt1 could be taken up into the macrophage cells via mannose receptors, and distributed and taken up into the liver and spleen, the target organs in the treatment of Gaucher's disease. Notably, the NbGNTI‐RNAi line, producing GC, was stable and the NbGNTI‐RNAi plants were viable and did not show any obvious phenotype. Therefore, it would provide a robust tool for the production of GC with customized N‐glycan structures.

Taliglucerase alfa is a beta-glucocerebrosidase enzyme replacement therapy approved in the United States, Israel, and other countries for treatment of Type 1 Gaucher disease in adults, and is the first approved plant cell--expressed recombinant protein. In this report, taliglucerase alfa pharmacokinetics were assessed in adult and pediatric patients with Gaucher disease from separate multicenter trials of 30 Units/kg and 60 Units/kg doses infused every 2 weeks. Serial blood samples were obtained from adult patients following single-dose administration on day 1 (n = 26) and multiple doses at week 38 (n = 29), and from pediatric patients following administration of multiple doses of taliglucerase alfa for 10-27 months (n = 10). In both adult and pediatric patients, maximum plasma concentration (Cmax), area under the plasma concentration-time curve from time zero to last measureable concentration (AUC0-t), and from time zero to infinity (AUC0-∞) were higher after 60 Units/kg dose than 30 Units/kg dose. No tendency for accumulation or change in taliglucerase alfa pharmacokinetic parameters over time from day 1 to week 38 was observed with repeated doses of 30 or 60 Units/kg in adults. After multiple doses, mean (range) dose-normalized pharmacokinetic parameters were similar for adult versus pediatric patients receiving 60 Units/kg: Cmax expressed in ng/mL/mg was 42.4 (14.5-95.4) in adults and 46.6 (34.4-68.4) in pediatric patients, AUC0 t expressed in ng • h/mL/mg was 63.4 (26.3-156) in adults and 63.9 (39.8-85.1) in pediatric patients, t1/2 expressed in minutes was 34.8 (11.3-104) in adults and 31.5 (18.0-42.9) in pediatric patients and total body clearance expressed in L/h was 19.9 (6.25-37.9) in adults and 17.0 (11.7-24.9) in pediatric patients. These pharmacokinetic data extend the findings of taliglucerase alfa in adult and pediatric patients. ClinicalTrials.gov. NCT00376168 (in adults); NCT01411228 (in children).

Background Enzyme replacement therapy (ERT) is currently the standard treatment for patients with Gaucher disease type I (GD1), but the pharmacokinetics have hardly been studied. This study aimed to quantify in vivo enzyme activity in peripheral leukocytes from patients receiving long-term treatment with imiglucerase or velaglucerase for GD1, and set out to assess the process of enzymatic uptake by peripheral leukocytes. Methods A prospective semi-experimental study was conducted. Four time points for blood withdrawal were planned per patient to quantify the intra-leukocyte enzymatic activity. In order to assess the uptake process, the rate of enzyme uptake by leukocytes (Rupt) and the rate of enzyme disappearance from the plasma (Rdis) were estimated. Results Eight GD1 patients were included. Intra-leukocyte activity was 24.31 mU/mL [standard deviation (SD) 6.32 mU/mL; coefficient of variation (CV) 25.96 %] at baseline and 27.14 mU/mL (SD  6.96 mU/mL; CV 25.65 %) at 15 min post-perfusion. The relationships with the administered dose were linear. The Rupt value was 37.73 mU/mL/min [95 % confidence interval (CI) 25.63–49.84] and showed a linear correlation with the administered enzyme dose ( p  < 0.05), and the Rdis value was 189.43 mU/mL/min (95 % CI 80.31–298.55) and also showed a linear correlation with the dose ( p  < 0.05). Conclusion This was the first in vivo study to quantify the accumulated enzymatic activity in patients receiving ERT for GD1. It showed that intra-leukocyte activity at baseline and at 15 min post-perfusion could be used as a possible marker for therapeutic individualization in patients receiving ERT for GD1.

Gaucher disease type 1 is caused by the defective activity of the lysosomal enzyme, acid beta-glucosidase (GCase). Regular infusions of purified recombinant GCase are the standard of care for reversing hematologic, hepatic, splenic, and bony manifestations. Here, similar in vitro enzymatic properties, and in vivo pharmacokinetics and pharmacodynamics (PK/PD) and therapeutic efficacy of GCase were found with two human GCases, recombinant GCase (CHO cell, imiglucerase, Imig) and gene-activated GCase (human fibrosarcoma cells, velaglucerase alfa, Vela), in a Gaucher mouse, D409V/null. About 80+% of either enzyme localized to the liver interstitial cells and <5% was recovered in spleens and lungs after bolus i.v. injections. Glucosylceramide (GC) levels and storage cell numbers were reduced in a dose (5, 15 or 60 U/kg/wk) dependent manner in livers (60-95%) and in spleens ( approximately 10-30%). Compared to Vela, Imig (60 U/kg/wk) had lesser effects at reducing hepatic GC (p = 0.0199) by 4 wks; this difference disappeared by 8 wks when nearly WT levels were achieved by Imig. Anti-GCase IgG was detected in GCase treated mice at 60 U/kg/wk, and IgE mediated acute hypersensitivity and death occurred after several injections of 60 U/kg/wk (21% with Vela and 34% with Imig). The responses of GC levels and storage cell numbers in Vela- and Imig-treated Gaucher mice at various doses provide a backdrop for clinical applications and decisions.

Direct enzyme replacement therapy (ERT) has been introduced as a means to treat a number of rare, complex genetic conditions associated with lysosomal dysfunction. Gaucher disease was the first for which this therapy was applied and remains the prototypical example. Although ERT using recombinant lysosomal enzymes has been shown to be effective in altering the clinical course of Gaucher disease, Fabry disease, Hurler syndrome, Hunter syndrome, Maroteaux-Lamy syndrome, and Pompe disease, the recalcitrance of certain disease manifestations underscores important unanswered questions related to dosing regimes, tissue half-life of the recombinant enzyme and the ability of intravenously administered enzyme to reach critical sites of known disease pathology. We have developed an innovative method for tagging acid β-glucocerebrosidase (GCase), the recombinant enzyme formulated in Cerezyme® used to treat Gaucher disease, using an ¹⁸F-labeled substrate analogue that becomes trapped within the active site of the enzyme. Using micro-PET we show that the tissue distribution of injected enzyme can be imaged in a murine model and that the PET data correlate with tissue ¹⁸F counts. Further we show that PET imaging readily monitors pharmacokinetic changes effected by receptor blocking. The ability to ¹⁸F-label GCase to monitor the enzyme distribution and tissue half-life in vivo by PET provides a powerful research tool with an immediate clinical application to Gaucher disease and a clear path for application to other ERTs.

Gaucher disease (GD) is the most common lysosomal storage disease, (frequency of 1:40,000 to 1:60,000). Ninety-Five percent of patients have type 1 (nonneuropathic type). Symptomatic patients with type 1 GD are treated with enzyme replacement therapy (ERT) to improve disease-induced effects on hemoglobin, platelets, and liver and spleen volume. Currently, several ERTs are available. The goal of this article was to review the pharmacology, efficacy, and safety data available for the use of a recently approved ERT, velaglucerase alfa, for the treatment of type 1 GD in symptomatic pediatric and adult patients. Serial searches of MEDLINE, EMBASE, and Cochrane databases for English-language, peer-reviewed, clinical data (using the search term velaglucerase alfa) were completed, with the final search in November 2011. All identified, peer-reviewed published human data were used for this review. Due to minimal peer-reviewed published data, those data reported via clinical trial registries or in the form of published abstracts were included. The manufacturer was contacted and given the opportunity to submit supplemental data for consideration of inclusion by the author. Velaglucerase alfa is produced through gene activation technology and is identical to wild-type enzyme. As with other ERTs for type 1 GD, velaglucerase alfa targets accumulated glucocerebroside primarily within the lysosome of the macrophages in the affected organs and systems. When administered at doses of 60 U/kg intravenously, velaglucerase alfa follows linear pharmacokinetics and is rapidly eliminated, with a mean (SD) residence time or time for 63% of the dose to be cleared from systemic circulation of 14 (4) minutes. Four trials and early access program data reporting efficacy were identified for this review: 5 peer-reviewed publications, 3 clinical trial registry reports, and 1 abstract-only publication. Phase I/II data with an extension phase (n = 12) showed significant improvements (all, P < 0.004) in hemoglobin concentrations (21.7%), platelet counts (157.8%), and hepatic (−42.8%) and spleen (−79.3%) volumes at 48 months. Bone mineral density data reported out to 69 months for this extension population noted significant improvements in z score slope for both lumbar spine (0.14 z score unit per year; P < 0.01) and femoral head (0.08 z score unit per year; P < 0.01). Benchmarking of 7 patients with complete clinical datasets at 57 months identified achievement and maintenance of therapeutic goals set by the International Collaborative Gaucher Group for anemia, platelet counts, hepatosplenomegaly, and bone mineral density. Thirty-eight patients enrolled in an open-label, therapy-switch trial who received velaglucerase alfa at doses consistent with current doses of imiglucerase maintained hemoglobin (−0.101 g/dL [95% CI, −0.272 to 0.07]) and platelet counts (7.04% [95% CI, 0.54% to 13.53%]) at 53 weeks after therapy change. Phase III data evaluating 2 dosing regimens of velaglucerase alfa 60 and 45 U/kg intravenously every other week reported significant improvements in most measured clinical parameters at 12 months: hemoglobin concentrations (60 U/kg, 2.429 [0.324] g/dL [P < 0.0001]; 45 U/kg, 2.438 g/dL [95% CI, 1.488 to 3.389]), platelet counts (60 U/kg, 50.88 × 109/L [95% CI, 23.97 to 77.78]; 45 U/kg, 40.92 × 109/L [95% CI, 11.2 to 70.64]), spleen volumes (60 U/kg, −1.92% of body weight [95% CI, −3.04 to −0.79]; 45 U/kg, −1.87% of body weight [95% CI, −3.17 to −0.57]), and hepatic volumes (60 U/kg, −0.84% of body weight [95% CI, −1.58 to −0.11]). A subanalysis of the pediatric population showed clinical improvements at 12 months in both dosing groups: hemoglobin concentrations (60 U/kg, 1.74 g/dL [95% CI, 0.72 to 2.78]; 45 U/kg, 2.77 g/dL [95% CI, −0.99 to 6.53]), platelet counts (60 U/kg, 49.9 × 109/L [95% CI, −32.1 to 131.9]; 45 U/kg, 60.3 × 109/L [95% CI, −103.1 to 223.7]), spleen volumes (60 U/kg, −2.1 cm3 [95% CI, −5.3 to 1.1]; 45 U/kg, −0.7 cm3 [95% CI, −2.6 to 1.2]), and hepatic volumes (60 U/kg, −0.7 cm3 [95% CI, −1.4 to 0.0]; 45 U/kg, −0.3 cm3 [95% CI, −1.7 to 1.1]). Data comparing velaglucerase alfa with imiglucerase identified similar changes in hemoglobin concentrations at 1.624 g/dL and 1.488 g/dL, respectively, after 9 months of therapy. Safety was reported in 3 identified studies and in data reported from the early access program: 3 peer-reviewed publications, 3 studies reported in clinical trial registries, and 1 abstract publication. Patients experienced a minimal number of adverse effects, and most reactions were mild to moderate in severity; 1 patient developed an anaphylactoid reaction and was discontinued from the trial. Antibody formation has been described with velaglucerase alfa but when compared with that of imiglucerase, seroconversion is less frequent (1% and 23%, respectively). Dosing regimens, from 30 to 60 U/kg intravenously every other week, have been assessed. Currently, the manufacturer recommends 60 U/kg intravenously every other week; however, further studies and evaluation of current study dosing regimens are needed to determine if there is a lower effective dose. Although a minimal amount of data are available for this relatively new biological agent, velaglucerase alfa reportedly is effective in the achievement and maintenance of therapeutic goals in type 1 GD in both treatment-naive and patients previously treated with imiglucerase. This agent has been reasonably well tolerated in clinical trials and may be considered for use in symptomatic patients with type 1 GD.

Dear Dr. Shader: We read with great interest the Research Letter published by Sekijima et al.1 The authors describe the successful lactation outcome of an infant whose mother, a patient with Gaucher disease (GD), a lysosomal disorder caused by deficient activity of β-glucocerebrosidase, was receiving enzyme replacement therapy (ERT) with imiglucerase (a modified β-glucocerebrosidase produced in CHO cells). Because breastfeeding can decrease maternal bone mineral density, attention to proper dietary intake is required.

Background: Enzyme replacement therapy (ERT) with imiglucerase is a well-established, effective treatment for Gaucher disease. However, there have been no published reports regarding the excretion of imiglucerase into human breast milk and its effects on the nursing infant. Objective: This letter reports on the successful pregnancy and lactation of a patient with Gaucher disease receiving treatment with imiglucerase, and the subsequent distribution and excretion of imiglucerase in human breast milk. Methods: A 39-year-old Japanese female (height, 164 cm; weight, 55 kg) with Gaucher disease had 2 successful pregnancies and continued ERT through both. The study was conducted 6 months after the first delivery. She was administered a 1-hour infusion of imiglucerase 60 U/kg that coincided with her regular every-2-week regimen. Serum and breast-milk samples were obtained before and up to 24 hours after administration. Breast-milk samples were also obtained from 10 nursing mothers with galactorrhea as controls. Results: The preinfusion level of breast-milk β-glucocerebrosidase was 0.008 nmol/h/mL. The peak of serum β-glucocerebrosidase activity (0.119 nmol/h/mL) was obtained at the end of the 1-hour infusion period. Slightly increased enzymatic activity (0.016 nmol/h/mL) was observed in the first breast milk sampled after imiglucerase infusion. Conclusions: We report a case of successful pregnancy and breastfeeding in a Japanese patient with Gaucher disease. A small amount of imiglucerase was found to be excreted into human breast milk, but only in the first milk produced after infusion.