Switching from originator recombinant growth hormone (Genotropin™) to biosimilar (CRISCY™): Results from a 6-month, multicentric, non-inferiority, extension trial

OBJECTIVE

A previous 12-month comparative trial with Criscy™ (r-hGH Cristália), a biosimilar recombinant growth hormone, demonstrated equivalent efficacy and safety to Genotropin™. This extension trial evaluated the effects of switching patients treated with Genotropin™ to the biosimilar Criscy™ over an additional 6-month treatment period, comparing efficacy, safety, and immunogenicity parameters with patients remaining in the Criscy™ arm.

DESIGN

This extension study included 11 research centers and 81 patients who participated in the CERES study (Czepielewski et al., 2019 [1]). Participants from the Genotropin™ arm (n = 39) had the drug replaced by Criscy™ and the remaining participants were kept in the Criscy™ arm (n = 42) for an additional 6-month period to evaluate immunogenicity, efficacy (growth rate, height SDS), and safety (laboratory tests, and adverse events).

RESULTS

Before the switch, both Criscy™ and Genotropin groups were similar concerning demographics, and auxological measures: age, sex, height, height SDS, weight, and BMI. Height velocity (HV) after 18 months of treatment was 8.7 ± 1.56 cm/year for Criscy™ group and 8.9 ± 1.36 cm/year for Genotropin™ group in the ITT population (p = 0.43). The auxological parameters and IGF-1 and IGFBP-3 SDS were comparable between both groups of patients. No participants were excluded from the study due to adverse events. There were no clinical or statistical relevant differences between the treatment groups concerning frequency, distribution, intensity, and AEs outcome. Similarly, no new anti-r-hGH (ADA) cases among patients that switched from Genotropin™ to Criscy™ were reported. No neutralizing antibody (nAb) was detected in either group.

CONCLUSIONS

This trial showed that switching from originator recombinant human growth hormone to Criscy™ had no impact on efficacy, safety, nor immunogenicity as compared to continued treatment with Criscy™. Growth rates and ADA incidence remained the same as seen before the switch.

The crystal structure of the cysteine protease Xylellain from Xylella fastidiosa reveals an intriguing activation mechanism

Xylella fastidiosa is responsible for a wide range of economically important plant diseases. We report here the crystal structure and kinetic data of Xylellain, the first cysteine protease characterized from the genome of the pathogenic X. fastidiosa strain 9a5c. Xylellain has a papain-family fold, and part of the N-terminal sequence blocks the enzyme active site, thereby mediating protein activity. One novel feature identified in the structure is the presence of a ribonucleotide bound outside the active site. We show that this ribonucleotide plays an important regulatory role in Xylellain enzyme kinetics, possibly functioning as a physiological mediator.

Effects of Trypanosoma brucei tryptophanyl-tRNA synthetases silencing by RNA interference

The kinetoplast genetic code deviates from the universal code in that 90% of mitochondrial tryptophans are specified by UGA instead of UGG codons. A single nucleus-encoded tRNA Trp(CCA) is used by both nuclear and mitochondria genes, since all kinetoplast tRNAs are imported into the mitochondria from the cytoplasm. To allow decoding of the mitochondrial UGA codons as tryptophan, the tRNA Trp(CCA) anticodon is changed to UCA by an editing event. Two tryptophanyl tRNA synthetases (TrpRSs) have been identified in Trypanosoma brucei: TbTrpRS1 and TbTrpRS2 which localize to the cytoplasm and mitochondria respectively. We used inducible RNA interference (RNAi) to assess the role of TbTrpRSs. Our data validates previous observations of TrpRS as potential drug design targets and investigates the RNAi effect on the mitochondria of the parasite.

Biochemical and Structural Characterization of Salmonella typhimurium Glyoxalase II: New Insights into Metal Ion Selectivity,

Glyoxalase II is a hydrolytic enzyme part of the glyoxalase system, responsible for detoxifying several cytotoxic compounds employing glutathione. Glyoxalase II belongs to the superfamily of metallo-beta-lactamases, with a conserved motif able to bind up to two metal ions in their active sites, generally zinc. Instead, several eukaryotic glyoxalases II have been characterized with different ratios of iron, zinc, and manganese ions. We have expressed a gene coding for a putative member of this enzyme superfamily from Salmonella typhimurium that we demonstrate, on the basis of its activity, to be a glyoxalase II, named GloB. Recombinant GloB expressed in Escherichia coli was purified with variable amounts of iron, zinc, and manganese. All forms display similar activities, as can be shown from protein expression in minimal medium supplemented with specific metal ions. The crystal structure of GloB solved at 1.4 A shows a protein fold and active site similar to those of its eukaryotic homologues. NMR and EPR experiments also reveal a conserved electronic structure at the metal site. GloB is therefore able to accommodate these different metal ions and to carry out the hydrolytic reaction with similar efficiencies in all cases. The metal promiscuity of this enzyme (in contrast to other members of the same superfamily) can be accounted for by the presence of a conserved Asp residue acting as a second-shell ligand that is expected to increase the hardness of the metal binding site, therefore favoring iron uptake in glyoxalases II.

Preliminary X-ray diffraction studies of rabbit muscle triose phosphate isomerase (TIM)

Triose phosphate isomerase (TIM) is responsible for the interconversion between GAP and DHAP in the glycolytic pathway. Two crystal forms belonging to space group P2(1)2(1)2(1) were obtained by the hanging-drop method and were designated A and B. Synchrotron X-ray diffraction data were collected for both forms. Form A had unit-cell parameters a = 65.14, b = 72.45, c = 93.24 A and diffracted to 2.25 A at 85 K, whereas form B had unit-cell parameters a = 73.02, b = 79.80, c = 172.85 A and diffracted to 2.85 A at room temperature. Molecular replacement was employed to solve the structures, using human TIM as a search model. Further refinement of both structures is under way and is expected to shed light on the recently reported conformational studies for rabbit TIM.