Development of a Biosimilar of Agalsidase Beta for the Treatment of Fabry Disease: Preclinical Evaluation.

BACKGROUND AND OBJECTIVE: Fabry disease (FD) is a rare lysosomal storage disorder caused by a deficiency of the enzyme α-galactosidase A (aGal A). Since 2001, two different enzyme replacement therapies have been authorized, with agalsidase beta being used in most parts of the Western world. Currently, biosimilars of several expensive enzyme therapies are under development to improve their accessibility for patients. We present the preclinical results of the development of a biosimilar to agalsidase beta. METHODS: Produced in a Chinese hamster ovary (CHO)-cell system, the biosimilar aGal A Biosidus (AGABIO), was compared with agalsidase beta with respect to amino acid sequence, glycosylation, specific α-galactosidase activity, stability in plasma, and effects on cultured human Fabry fibroblasts and Fabry mice. RESULTS: AGABIO had the same amino acid composition and similar glycosylation, enzymatic activity, and stability as compared with agalsidase beta. After uptake in fibroblasts, α-galactosidase A activity increased in a dose-dependent manner, with maximum uptake observed after 24 h, which remained stable until at least 48 h. Both enzymes were localized to lysosomes. Reduction of accumulated globotriaosylceramide (Gb3) and lysoGb3 in cultured Fabry fibroblasts by AGABIO and agalsidase beta showed comparable dose-response curves. In Fabry knockout mice, after a single injection, both enzymes were rapidly cleared from the plasma and showed equal reductions in tissue and plasma sphingolipids. Repeated dose studies in rats did not raise any safety concerns. Anti-drug antibodies from patients with FD treated with agalsidase beta showed equal neutralization activity toward AGABIO. CONCLUSION: These findings support the biosimilarity of AGABIO in comparison with agalsidase beta. The clinical study phase is currently under development.

Immunoglobulin gene rearrangements and mutational status in argentinian patients with chronic lymphocytic leukemia.

BACKGROUND: Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease. The mutational status of the immunoglobulin heavy chain variable (IGHV) region represents one of the best prognostic markers and defines 2 disease subgroups: mutated (M-CLL) and unmutated (UM-CLL), with different clinical course. MATERIALS AND METHODS: IGHV-D-J gene rearrangements and mutational status were analyzed in 73 Argentinian patients with CLL, 22 previously treated, by reverse transcriptase-polymerase chain reaction and bidirectional sequencing. The results were compared with those reported in other geographic regions. Fluorescence in situ hybridization analysis was also performed. RESULTS: A total of 43 (58.9%) cases were of patients with M-CLL, and 30 (41.1%) were patients with UM-CLL. Deletion of chromosome 13q14 as a single alteration was more frequently observed in the M-CLL group (48%) than in the UM-CLL group (24%). In the M-CLL group, the proportion of cases with deletion of chromosome 13q14 was significantly higher than those with +12 and those with deletions of chromosomes 17p and 11q (P = .003). The most frequently used IGHV families were IGHV3 > IGHV1 > IGHV4, which are different from those observed in Asian, Brazilian, and Uruguayan series. The IGHV3-23 gene (10.8%) was the most commonly used, followed by IGHV1-69 (9.5%), IGHV4-59 and IGHV2-5 (6.8% each), and IGHV3-21 and IGHV3-30 (5.4% each). IGHV4-34 showed the lowest frequency (2.7%) in our cohort compared with published data, whereas IGHV4-59, IGHV3-72, and IGHV2-5 were overexpressed in our series. Stereotyped HCDR3 (heavy chain complementary determining region 3) was found in 9.5% of patients. CONCLUSIONS: Our results showed that Argentinian patients with CLL display an IGHV gene usage that resembles that observed in Western countries and exhibited interesting similarities and differences with respect to published series from other Latin American populations, which reflect variations in the genetic background.

Structural alterations in chronic lymphocytic leukaemia. Cytogenetic and FISH analysis.

In this study, we described cytogenetics and fluorescence in situ hybridization (FISH) analysis performed in chronic lymphocytic leukaemia (CLL) patients with structural alterations. Results were correlated with clinical characteristics. A total of 38 CLL patients: 16 cases with complex and 22 with simple karyotypes were studied. For comparison of clinical parameters, a control group of 78 CLL patients with normal karyotype and without FISH genomic alterations were also evaluated. We found 38 structural abnormalities not previously described in the literature, 28 (74%) of them were translocations. In cases with complex karyotypes, chromosomes 6, 8 and 13 were the most frequently involved in new alterations (nine each), followed by chromosomes 12, 14 and 15 (six each). Chromosome 8p was particularly involved in losses, being 8p21-pter the commonest region of overlap. Cases with simple karyotypes, showed del(6q) as the most frequent alteration (39%). Del(9)(q11) was recurrent in our series. Analysis of clinical parameters showed significant differences in white blood count (p = 0.005) and platelet count (p = 0.015) between patients with structural alterations and the control group. In addition, patients with structural alterations had a significantly shorter time to first treatment (TFT) (29 months) than the control group (69 months) (p = 0.037). Cases with complex karyotypes had a lower proportion of patients in Rai 0 clinical stage (15.4% vs 75%) (p = 0.005) and higher ß2 microglobulin levels (3.3 vs 2.5 µg/mL) (p = 0.037) than those with simple karyotypes. Furthermore, a shorter TFT (13 months) and overall survival (56 months) in the complex karyotypes group compared with controls (69 and 144 months, respectively) (p = 0.015 and p = 0.005, respectively) were also found. Our results support the importance of cytogenetic analysis for clinical outcome in CLL and suggest that the diversity of genomic alterations is much greater than previously appreciated.