Characteristics of the preparation
Sebelipase alpha is a recombinant human lysosomal acid lipase (rhLAL), purified from the egg protein of transgenic chickens, with the same amino acid sequence as the native human enzyme. Purified amylipase alpha is a glycoprotein with 6 N-linked sites of glycosylation. The glycans of the amylipase alpha are mainly composed of N-acetylglucosamine (GlcNAc) and N-linked structures terminating in mannose, as well as mannose-6-phosphate fragments. Described N-glikanovye structure facilitates the absorption of the protein in the macrophage cells via mannose or mannose-6-phosphate receptor.
Farmacodynamics
Sebelipaza alpha - recombinant lysosomal acidic lipase, an enzyme which is used as an enzyme replacement therapy, in order to improve lipid metabolism and reduce the accumulation of cholesterol esters and triglycerides in patients of all ages under deficiency of lysosomal acidic lipase (DLKL).
The deficiency of lysosomal acid lipase (historically Wolman's disease, the accumulation of cholesterol esters) is a rare autosomal recessive lysosomal accumulation disease characterized by a genetic defect LAL gene, and leading to a marked decrease or loss of activity of the enzyme lysosomal acid lipase (LCL). This deficiency is characterized by the absence of cleavage of cholesterol esters and triglycerides in lysosomes.
Lysosomal accumulation of esters of cholesterol and triglycerides in the liver leads to hepatomegaly, an increase in the specific proportion of fat in the hepatic tissue, an increase in the levels of transaminases,signaling chronic liver damage, as well as progression to fibrosis, cirrhosis and complications of the terminal stage of liver failure. In the spleen, DLL causes splenomegaly, in the blood - anemia and thrombocytopenia. The accumulation of lipids in the intestinal wall leads to malabsorption and disruption of growth and development. Dyslipidemia is often accompanied by a rise in low-density lipoprotein (LDL) and triglyceride levels and a decrease in high-density lipoprotein (HDL) and is associated with an increase in the specific percentage of fat in liver tissue and a rise in the level of transaminases in the blood. Patients with DLLL have an increased risk of developing cardiovascular disease and a higher rate of atherosclerosis. Deficiency of the enzyme also leads to a decrease in the production of free cholesterol, which leads to an increase in the synthesis of apo-B-containing lipoproteins and slowing down the formation of HDL particles.
Other lipid-modifying agents can lower LDL cholesterol in patients with LDL, but they do not affect the progression of liver disease, since these drugs do not affect the underlying cause of the enzyme deficiency.
Based on the results of experimental pharmacological data and clinical studies, it was shown that KANUMA preparation, being a pathogenetic agent of DLLL therapy, promotes improvement of lipid metabolism and normalization of hepatic enzymes level in conditions associated with DLLL.
Mechanism of action
Sebelipase alpha binds to cell membrane receptors through glycans expressed on a protein and is subsequently absorbed by lysosomes. Sebelipase alfa catalyzes the lysosomal hydrolysis of esters of cholesterol and triglycerides to free cholesterol, glycerol and free fatty acids. Substitution of enzymatic activity of LCL leads to a decrease in the specific percentage of fat in liver tissue and normalization the level of transaminases in the blood, and also restores the metabolism of cholesterol and triglyceride esters in lysosomes, which leads to lower levels of low-density lipoprotein (LDL) cholesterol and low-density lipoprotein (LNVV), triglycerides, and high-density lipoprotein (HDL) cholesterol. Improved growth and development of the body occurs as a result of a decrease in the accumulation of lipids in the wall of the intestine and, as a consequence,improve the absorption of nutrients.
Clinical efficacy and safety
Research the children with newly diagnosed deficiency of lysosomal acid lipase
Study LAL-CL03 was a multicentre open noncomparative study of the drug KANUMA in 9 patients with DLL with developmental disability or other signs of rapidly progressing disease at the age of up to 6 months. Patients also suffered rapidly progressive insufficiency of liver function and severe hepatosplenomegaly. The age range for inclusion in the study was 1-6 months. Patients received the drug KANUMA at a dose of 0.35 mg / kg once a week for the first 2 weeks and then 1 mg / kg once a week. According to the clinical response, the dose was raised to 3 mg / kg once a week after 1 month and up to 20 months from the start of treatment at a dose of 1 mg / kg. It was allowed to further increase the dose to 5 mg / kg once a week.
Efficacy was assessed by comparing the survival experience of patients treated with KANUMA, who survived to age 12 months and older in the study LAL CL03, with a historical cohort of untreated infants who have been diagnosed with DLL with similar clinical symptoms. In the study LAL CL03 Six out of nine infants who received the drug KANUMA survived to 12 months or more (67% 12 month survival, 95% CI: 30% to 93%). With the continuation of treatment after 12 months of age, 1 patient died at the age of 15 months. In a historical cohort, 0 out of 21 patients experienced an 8-month age (0% 12 month survival, 95 % CI: 0% to 16 %).
Taking the drug KANUMA in doses up to 1 mg / kg once a week led to an improvement in the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (ACT) and to weight gain during the first few weeks of treatment. From baseline to week 48, average ALT decline and ACT were 34.0 U / L and 44.5 U / L, respectively. An increase in the dose to 3 mg / kg once a week was associated with an additional improvement in the indices of weight gain, lymphadenopathy and serum albumin. From baseline to week 48, the average percentile of mass body by age improved from 12.74 % up to 29.83%, and the average serum albumin levels rose from 26.7 g / l to 38.7 g / l.
Children and adults with a deficiency of lysosomal acid lipase
Study LAL-CL02 was a multicenter, double-blind, placebo-controlled study conducted in 66 children and adults with DLLL. Patients were randomized to receive CAIUM preparation at a dose of 1 mg / kg (n = 36) or placebo (n = 30) once every two weeks for 20 weeks of a double-blind period. The age range at the time of randomization was 4-58 years (71% of patients <18 years old). To enter the study, patients were required to have ALT at 1.5 upper limit of the norm (VGN). In the majority of patients (58%), the level of cholesterol was> 190 mg / dl when included in the study; 24% of patients with LDL cholesterol> 190 ml / dL received lipid-lowering medications. Of the 32 patients who underwent liver biopsy at the time of enrollment, 100% had fibrosis and 31 % cirrhosis. The age range of patients with signs of cirrhosis, confirmed by biopsy, was 4-21 years.
The following endpoints were evaluated: normalization of ALT level, lowering of LDL cholesterol level, lowering of LDL cholesterol level, normalization of level ACT, decrease in triglyceride levels, increase in HDL cholesterol level, decrease in the specific percentage of fatty tissue of the liver, assessed by means of magnetic resonance tomography in the regime of multiple gradient echo (MEGE-MRI), and a decrease in the degree of fatty liver dystrophy measured by morphometry.
A statistically significant improvement in multiple endpoints was observed in the group treated with KANUMA compared with the placebo group at the end of the 20-week, double-blind study period. The absolute decrease in the average level of ALT was 57.9 U / l (-53%) in the group treated with CAIUMA and 6.7 U / L (-6 %) in the placebo group.
Paired liver biopsies at baseline and week 20 were available in a subpopulation of patients (n = 26). Of patients with paired liver biopsies in 63 % (10/16) treated with KANUMA, a reduction in fatty liver was recorded (at least 5 % decrease), which was measured by morphometry compared with 40% (4/10) of patients on placebo. This difference was not statistically significant.
Open period
Sixty-five of the 66 patients entered the open period (up to 130 weeks) with the introduction drug KANUMA in a dose of 1 mg / kg once every two weeks. In patients who received the drug KANUMA during the double-blind period, there was a decrease in ALT levels achieved during the first 20 weeks of treatment and further improvement of lipid parameters was observed,including LDL cholesterol and HDL cholesterol levels.
In patients on placebo, elevated levels of serum transaminases and abnormalities in serum lipid levels persisted during the double-blind period. In accordance with the facts observed in patients treated with KANUMA during the double-blind period, the onset of KANUMA treatment during the open period resulted in a rapid improvement in ALT and lipid levels, including LDL cholesterol and LDL cholesterol levels.
In a separate open study (LAL CL01/LAL CL04) in adults with DLLL, an improvement in serum transaminase levels and lipid levels persisted throughout the 104-week treatment period.
Pediatric population
Age 56 of 84 patients (67 %), who received the drug KANUMA during clinical trials (LAL-CL01/LAL-CL04, LAL-CL02 and LAL-CL03), was in the pediatric and adolescent range (from 1 month to 18 years).