Raul Chertkoff

Pivotal trial with plant cell-expressed recombinant glucocerebrosidase, taliglucerase alfa, a novel enzyme replacement therapy for Gaucher disease

Taliglucerase alfa (Protalix Biotherapeutics, Carmiel, Israel) is a novel plant cell-derived recombinant human β-glucocerebrosidase for Gaucher disease. A phase 3, double-blind, randomized, parallel-group, comparison-dose (30 vs 60 U/kg body weight/infusion) multinational clinical trial was undertaken. Institutional review board approvals were received. A 9-month, 20-infusion trial used inclusion/exclusion criteria in treatment-naive adult patients with splenomegaly and thrombocytopenia. Safety end points were drug-related adverse events: Ab formation and hypersensitivity reactions. Primary efficacy end point was reduction in splenic volume measured by magnetic resonance imaging. Secondary end points were: changes in hemoglobin, hepatic volume, and platelet counts. Exploratory parameters included biomarkers and bone imaging. Twenty-nine patients (11 centers) completed the protocol. There were no serious adverse events; drug-related adverse events were mild/moderate and transient. Two patients (6%) developed non-neutralizing IgG Abs; 2 other patients (6%) developed hypersensitivity reactions. Statistically significant spleen reduction was achieved at 9 months: 26.9% (95% confidence interval [CI]: -31.9, -21.8) in the 30-unit dose group and 38.0% (95% CI: -43.4, -32.8) in the 60-unit dose group (both P < .0001); and in all secondary efficacy end point measures, except platelet counts at the lower dose. These results support safety and efficacy of taliglucerase alfa for Gaucher disease.

A Phase 3, multicenter, open-label, switchover trial to assess the safety and efficacy of taliglucerase alfa, a plant cell-expressed recombinant human glucocerebrosidase, in adult and pediatric patients with Gaucher disease previously treated with imiglucerase

Taliglucerase alfa is a β-glucosidase enzyme replacement therapy (ERT) approved in the US and other countries for the treatment of Gaucher disease (GD) in adults and is approved in pediatric and adult patients in Australia and Canada. It is the first approved plant cell-expressed recombinant human protein. A Phase 3, multicenter, open-label, 9-month study assessed safety and efficacy of switching to taliglucerase alfa in adult and pediatric patients with GD treated with imiglucerase for at least the previous 2years. Patients with stable disease were offered taliglucerase alfa treatment using the same dose (9-60U/kg body weight) and regimen of administration (every 2weeks) as imiglucerase. This report summarizes results from 26 adult and 5 pediatric patients who participated in the trial. Disease parameters (spleen and liver volumes, hemoglobin concentration, platelet count, and biomarker levels) remained stable through 9months of treatment in adults and children following the switch from imiglucerase. All treatment-related adverse events were mild or moderate in severity and transient in nature. Exploratory parameters of linear growth and development showed positive outcomes in pediatric patients. These findings provide evidence of the efficacy and safety profile of taliglucerase alfa as an ERT for GD in patients previously treated with imiglucerase. This trial was registered at www.clinicaltrials.gov as # NCT00712348.

Taliglucerase alfa leads to favorable bone marrow responses in patients with type I Gaucher disease

Taliglucerase alfa (Protalix Biotherapeutics, Israel) is a carrot-cell-expressed recombinant human beta-glucocerebrosidase recently approved in the United States for the treatment of type 1 Gaucher disease (GD). As bone disease is one of the most debilitating features of GD, quantification of bone marrow involvement is important for monitoring the response to treatment. Therefore, bone marrow fat fraction (Ff) measured by quantitative chemical shift imaging (QCSI) was included as exploratory parameter to evaluate bone marrow response in treatment naïve GD patients participating in a double-blind, randomized phase III study. Eight GD patients with intact spleens were treated with 30 or 60U/kg biweekly. Ff results were compared to outcomes in 15 untreated Dutch GD patients with a follow-up interval of 1year. Five taliglucerase alfa treated patients had a Ff below the threshold that relates to complication risk (<0.23) at baseline (median (n=8) 0.19, range 0.11-0.35). Ff significantly increased compared to baseline (p=0.012) and compared to untreated patients (p=0.005), already after 1year of follow-up with further improvement up to 36months. In four patients with the lowest Ff, the higher dose resulted in increases above 0.23 within 1year. All patients had sustained improvements in all other parameters. There was no influence of antibodies on response parameters. Treatment with taliglucerase alfa results in significant increases in lumbar spine fat fractions, which indicates clearance of Gaucher cells from the bone marrow.

Enzyme replacement therapy with taliglucerase alfa: 36‐month safety and efficacy results in adult patients with Gaucher disease previously treated with imiglucerase

Taliglucerase alfa is the first available plant cell‐expressed human recombinant therapeutic protein. It is indicated for treatment of patients with type 1 Gaucher disease (GD) in adult and pediatric patients in several countries. Study PB‐06‐002 examined the safety and efficacy of taliglucerase alfa for 9 months in patients who previously received imiglucerase. The results of adult patients from Study PB‐06‐002 who continued receiving taliglucerase alfa in extension Study PB‐06‐003 for up to 36 months are reported here. Eighteen patients received at least one dose of taliglucerase alfa in Study PB‐06‐003; 10 patients completed 36 total months of therapy, and four patients who transitioned to commercial drug completed 30–33 months of treatment. In patients who completed 36 total months of treatment, mean percent (±standard error) changes from baseline/time of switch to taliglucerase alfa to 36 months were as follows: hemoglobin concentration, −1.0% (±1.9%; n = 10); platelet count, +9.3% (±9.8%; n = 10); spleen volume measured in multiples of normal (MN), −19.8% (±9.9%; n = 7); liver volume measured in MN, +0.9% (±5.4%; n = 8); chitotriosidase activity, −51.5% (±8.1%; n = 10); and CCL18 concentration, −36.5 (±8.0%; n = 10). Four patients developed antidrug antibodies, including one with evidence of neutralizing activity in vitro. All treatment‐related adverse events were mild or moderate and transient. The 36‐month results of switching from imiglucerase to taliglucerase alfa treatment in adults with GD provide further data on the clinical safety and efficacy of taliglucerase alfa beyond the initial 9 months of the original study. www.clinicaltrials.gov identifier NCT00705939. Am. J. Hematol. 91:661–665, 2016.

Safety and efficacy of two dose levels of taliglucerase alfa in pediatric patients with Gaucher disease

Taliglucerase alfa is a plant cell-expressed beta-glucocerebrosidase approved in the United States, Israel, Australia, Canada, and other countries for enzyme replacement therapy in adults with Type 1 Gaucher disease (GD), for treatment of pediatric patients in the United States, Australia, and Canada, and for the hematologic manifestations of Type 3 GD in pediatric patients in Canada. This multicenter, randomized, double-blind, parallel-dose, 12-month study assessed efficacy and safety of taliglucerase alfa in pediatric patients with GD. Eleven children were randomized to taliglucerase alfa 30U/kg (n=6) or 60U/kg (n=5) per infusion every other week. From baseline to month 12, the following changes were noted in the taliglucerase alfa 30-U/kg and 60-U/kg dose groups, respectively: median hemoglobin concentrations increased by 12.2% and 14.2%; the interquartile ranges of median percent change in hemoglobin levels from baseline were 20.6 and 10.4, respectively; mean spleen volume decreased from 22.2 to 14.0 multiples of normal (MN) and from 29.4 to 12.9 MN; mean liver volume decreased from 1.8 to 1.5 MN and from 2.2 to 1.7 MN; platelet counts increased by 30.9% and 73.7%; and chitotriosidase activity was reduced by 58.5% and 66.1%. Nearly all adverse events were mild/moderate, unrelated to treatment, and transient. One patient presented with treatment-related gastroenteritis reported as a serious adverse event due to the need for hospitalization for rehydration. No patient discontinued. These data suggest that taliglucerase alfa has the potential to be a therapeutic treatment option for children with GD. This study was registered at www.clinicaltrials.gov as NCT01132690.

Long-term efficacy and safety results of taliglucerase alfa up to 36 months in adult treatment-naïve patients with Gaucher disease.

Taliglucerase alfa is an intravenous enzyme replacement therapy approved for treatment of type 1 Gaucher disease (GD), and is the first available plant cell–expressed recombinant therapeutic protein. Herein, we report long‐term safety and efficacy results of taliglucerase alfa in treatment‐naïve adult patients with GD. Patients were randomized to receive taliglucerase alfa 30 or 60 U/kg every other week, and 23 patients completed 36 months of treatment. Taliglucerase alfa (30 U/kg; 60 U/kg, respectively) resulted in mean decreases in spleen volume (50.1%; 64.6%) and liver volume (25.6%; 24.4%) with mean increases in hemoglobin concentration (16.0%; 35.8%) and platelet count (45.7%; 114.0%), and mean decreases in chitotriosidase activity (71.5%; 82.2%). All treatment‐related adverse events were mild to moderate in intensity and transient. The most common adverse events were nasopharyngitis, arthralgia, upper respiratory tract infection, headache, pain in extremity, and hypertension. These 36‐month results of taliglucerase alfa in treatment‐naïve adult patients with GD demonstrate continued improvement in disease parameters with no new safety concerns. These findings extend the taliglucerase alfa clinical safety and efficacy dataset. www.clinicaltrials.gov identifier NCT00705939. Am. J. Hematol. 91:656–660, 2016.

Long‐term safety and efficacy results of taliglucerase alfa up to 36 months in adult treatment‐naïve patients with Gaucher disease

Taliglucerase alfa is an intravenous enzyme replacement therapy approved for treatment of type 1 Gaucher disease (GD), and is the first available plant cell–expressed recombinant therapeutic protein. Herein, we report long‐term safety and efficacy results of taliglucerase alfa in treatment‐naïve adult patients with GD. Patients were randomized to receive taliglucerase alfa 30 or 60 U/kg every other week, and 23 patients completed 36 months of treatment. Taliglucerase alfa (30 U/kg; 60 U/kg, respectively) resulted in mean decreases in spleen volume (50.1%; 64.6%) and liver volume (25.6%; 24.4%) with mean increases in hemoglobin concentration (16.0%; 35.8%) and platelet count (45.7%; 114.0%), and mean decreases in chitotriosidase activity (71.5%; 82.2%). All treatment‐related adverse events were mild to moderate in intensity and transient. The most common adverse events were nasopharyngitis, arthralgia, upper respiratory tract infection, headache, pain in extremity, and hypertension. These 36‐month results of taliglucerase alfa in treatment‐naïve adult patients with GD demonstrate continued improvement in disease parameters with no new safety concerns. These findings extend the taliglucerase alfa clinical safety and efficacy dataset. www.clinicaltrials.gov identifier NCT00705939. Am. J. Hematol. 91:656–660, 2016.

Long-term efficacy and safety results of taliglucerase alfa through 5years in adult treatment-naïve patients with Gaucher disease.

Taliglucerase alfa, the first available plant cell-expressed recombinant therapeutic protein, is an enzyme replacement therapy approved for Gaucher disease (GD). PB-06-001, a pivotal phase 3, multicenter, randomized, double-blind, parallel-dose study investigated taliglucerase alfa 30 or 60U/kg every other week through 9months in treatment-naïve adults with GD; 30-month extension study PB-06-003 followed. Patients completing PB-06-001 and PB-06-003 could continue treatment in PB-06-007. Nineteen patients enrolled in PB-06-007 (30U/kg, n=8; 60U/kg, n=9; dose adjusted, n=2); 17 completed 5 total years of treatment. In these 3 groups, respectively, taliglucerase alfa resulted in mean decreases in spleen volume (-8.7, -6.9, -12.4 multiples of normal), liver volume (-0.6, -0.4, -0.5 multiples of normal), chitotriosidase activity (-83.1%, -93.4%, -87.9%), and chemokine (CC motif) ligand 18 concentration (-66.7%, -83.3%, -78.9%), as well as mean increases in hemoglobin concentration (+2.1, +2.1, +1.8mg/dL) and platelet count (+31,871, +106,800, +34,000/mm3). The most common adverse events were nasopharyngitis and arthralgia. Most adverse events were mild/moderate; no serious adverse events were considered treatment-related. These results demonstrate continued improvement of disease parameters during 5years of taliglucerase alfa therapy in 17 treatment-naive patients with no new safety concerns, extending the taliglucerase alfa clinical efficacy and safety dataset. This study was registered at www.clinicaltrials.gov as NCT01422187.

Immunogenicity of glycans on biotherapeutic drugs produced in plant expression systems—The taliglucerase alfa story

Plants are a promising alternative for the production of biotherapeutics. Manufacturing in-planta adds plant specific glycans. To understand immunogenic potential of these glycans, we developed a validated method to detect plant specific glycan antibodies in human serum. Using this assay, low prevalence of pre-existing anti-plant glycan antibodies was found in healthy humans (13.5%) and in glucocerebrosidase-deficient Gaucher disease (GD) patients (5%). A low incidence (9% in naïve patient and none in treatment experienced patients) of induced anti-plant glycan antibodies was observed in GD patients after up to 30 months replacement therapy treatment with taliglucerase alfa, a version of human glucocerebrosidase produced in plant cells. Detailed evaluation of clinical safety and efficacy endpoints indicated that anti-plant glycan antibodies did not affect the safety or efficacy of taliglucerase alfa in patients. This study shows the benefit of using large scale human trials to evaluate the immunogenicity risk of plant derived glycans, and indicates no apparent risk related to anti-plant glycan antibodies.

Pharmacokinetics of Novel Plant Cell- Expressed Taliglucerase Alfa in Adult and Pediatric Patients with Gaucher Disease

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. Trial Registration ClinicalTrials.gov. NCT00376168 (in adults); NCT01411228 (in children)