Comparison of bioactivities of monopegylated rhG-CSF with branched and linear mPEG

Efficacy, safety, and cost-effectiveness of pegylated PEG-rhg-CSF in pediatric patients receiving high-intensity chemotherapy: results from a phase II study

Background

High-intensity chemotherapy can cause life-threatening complications in pediatric patients. Therefore, this study investigated safety and efficacy of long-acting pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF; Jinyouli®) in children undergoing high-intensity chemotherapy.

Methods

Treatment-naive patients received post-chemotherapy PEG-rhG-CSF as primary prophylaxis for two cycles. The primary endpoints were drug-related adverse events (AEs) and bone pain scores. Secondary endpoints included grade 3-4 neutropenia, duration of neutropenia recovery, absolute neutrophil count changes, febrile neutropenia (FN), reduced chemotherapy intensity, antibiotic usage, and AE severity. The cost-effectiveness of PEG-rhG-CSF was compared with that of rhG-CSF (Ruibai®).

Results

Here, 307 and 288 patients underwent one and two PEG-rhG-CSF cycles, respectively. Ninety-one patients experienced drug-related AEs, primarily bone pain (12.7%). Moreover, Grade 3-4 neutropenia and FN were observed. Median FN durations were 3.0 days in both cycles. No drug-related delays were observed during chemotherapy. One patient experienced grade 4 neutropenia-induced reduction in chemotherapy intensity during cycle 2. In total, 138 patients received antibiotics. PEG-rhG-CSF exhibited superior cost-effectiveness compared to rhG-CSF.

Conclusion

Our findings indicate that PEG-rhG-CSF is safe, efficient, and cost-effective in pediatric patients undergoing high-intensity chemotherapy, providing preliminary evidence warranting further randomized controlled trials.

Process Development for the Production and Purification of PEGylated RhG-CSF Expressed in Escherichia coli

Background and objective:

Recombinant human granulocyte-colony stimulating factor (rhG-CSF) and its PEGylated form (PEG-GCSF) are used in the cancer therapy. Thus the development of a more cost-effectively method for expressing rhG-CSF and the PEGylation optimization of rhG-CSF by reaction engineering and subsequent the purification strategy is necessary.

Methods:

RhG-CSF expression in Escherichia coli BL21 (DE3) was carried out by auto-induction batch fermentation and improved for maximizing rhG-CSF productivity. After that, purified rhG-CSF was PEGylated using methoxy polyethylene glycol propionaldehydes (mPEG20-ALD). The various conditions effect of extraction and purification of rhG-CSF and PEG-GCSF were assayed.

Results:

The assessment results revealed that auto-induction batch cultivation strategy had maximum productivity and rhG-CSF purity was more than 99%. The obtained Data of rhG-CSF PEGylation displayed that the optimized conditions of rhG-CSF PEGylation and purification enhanced hemogenisity PEG-GCSF and managed reaction toward optimal yield of PEG-GCSF (70%) and purity of 99.9%. Findings from FTIR, CD, and fluorescence spectroscopy and bioassay revealed that PEGylation was executed exactly in the rhG-CSF N-terminus, and products maintained their conformation properties.

Conclusion:

Overall, the developed approach expanded strategies for high yield rhG-CSF by simplified auto-induction batch fermentation system and rhG-CSF PEGylation, which are simple and time-saving, economical and high efficiency.

Comparing the efficacy and side-effects of PDLASTA® (Pegfilgrastim) with PDGRASTIM® (Filgrastim) in breast cancer patients: a non-inferiority randomized clinical trial

BACKGROUND

The objective of this study was to compare the efficacy and side effects of a single dose (Pegfilgrastim or PDL) or repeated six daily injections (Filgrastim or PDG) during chemotherapy courses in breast cancer patients in a non-inferiority clinical trial.

METHODS

In this randomized clinical trial, 80 patients were recruited and allocated randomly to two equal arms. In one group, a single subcutaneous dose of PDL was injected the day after receiving the chemotherapy regimen in each cycle. The second arm received a subcutaneous injection of PDG for six consecutive days in each cycle of treatment. The side effects of GCF treatment and its effect on blood parameters were compared in each cycle and during eight cycles of chemotherapy.

RESULTS

Hematologic parameters showed no significant differences in any of the treatment courses between the two study groups. The comparison of WBC (p = 0.527), Hgb (p = 0.075), Platelet (p = 0.819), Neutrophil (p = 0.575), Lymphocyte (p = 705) and ANC (p = 0.675) changes during the eight courses of treatment also revealed no statistically significant difference between the two study groups. Side effects including headache, injection site reaction and muscle pain had a lower frequency in patients receiving PDL drugs.

CONCLUSION

It seems that PDL is non-inferior in efficacy and also less toxic than PDG. Since PDL can be administered in a single dose and is also less costly, it can be regarded as a cost-effective drug for the treatment of chemotherapy-induced neutropenia.

TRIAL REGISTRATION

IRCT20190504043465N1 , May 2019.

A Novel PEGylation Method for Improving the Pharmacokinetic Properties of Anti-Interleukin-17A RNA Aptamers

The obstacles to the development of therapeutic aptamers for systemic inflammatory diseases, such as nuclease degradation and renal clearance, have not been fully overcome. Here, we report a novel PEGylation method, sbC-PEGylation, which improves the pharmacokinetic properties of RNA aptamers that act against interleukin-17A (IL-17A) in mice and monkeys. sbC-PEGylated aptamers were synthesized by coupling the symmetrical branching molecule 2-cyanoethyl-N,N-diisopropyl phosphoroamidite to the 5′ end of the aptamer, before conjugating two polyethylene glycol (PEG) molecules to the aptamer. Pharmacokinetic studies showed that compared with conventionally PEGylated aptamers, the sbC-PEGylated aptamer exhibited excellent stability in the blood circulation of mice and monkeys. In addition, one of the sbC-PEGylated aptamers, 17M-382, inhibited the interleukin-6 (IL-6) production induced by IL-17A in NIH3T3 cells in a concentration-dependent manner, and the half-maximal inhibitory concentration of sbC-PEGylated 17M-382 was two times lower than that of non-PEGylated 17M-382. Furthermore, the intraperitoneal administration of sbC-PEGylated 17M-382 significantly inhibited the IL-6 production induced by IL-17A in a mouse air pouch model. Our findings suggest that the novel PEGylation method described in this study, sbC-PEGylation, could be used to develop anti-IL-17A aptamers as a therapeutic option for systemic inflammatory disease.

Simplified in vitro refolding and purification of recombinant human granulocyte colony stimulating factor using protein folding cation exchange chromatography

Protein folding-strong cation exchange chromatography (PF-SCX) has been employed for efficient refolding with simultaneous purification of recombinant human granulocyte colony stimulating factor (rhG-CSF). To acquire a soluble form of renatured and purified rhG-CSF, various chromatographic conditions, including the mobile phase composition and pH was evaluated. Additionally, the effects of additives such as urea, amino acids, polyols, sugars, oxidizing agents and their amalgamations were also investigated. Under the optimal conditions, rhG-CSF was efficaciously solubilized, refolded and simultaneously purified by SCX in a single step. The experimental results using ribose (2.0M) and arginine (0.6M) combination were found to be satisfactory with mass yield, purity and specific activity of 71%, ≥99% and 2.6×10(8)IU/mg respectively. Through this investigation, we concluded that the SCX refolding method was more efficient than conventional methods which has immense potential for the large-scale production of purified rhG-CSF.

Site-specific PEGylation of therapeutic proteins via optimization of both accessible reactive amino acid residues and PEG derivatives

Modification of accessible amino acid residues with poly(ethylene glycol) [PEG] is a widely used technique for formulating therapeutic proteins. In practice, site-specific PEGylation of all selected/engineered accessible nonessential reactive residues of therapeutic proteins with common activated PEG derivatives is a promising strategy to concomitantly improve pharmacokinetics, allow retention of activity, alleviate immunogenicity, and avoid modification isomers. Specifically, through molecular engineering of a therapeutic protein, accessible essential residues reactive to an activated PEG derivative are substituted with unreactive residues provided that protein activity is retained, and a limited number of accessible nonessential reactive residues with optimized distributions are selected/introduced. Subsequently, all accessible nonessential reactive residues are completely PEGylated with the activated PEG derivative in great excess. Branched PEG derivatives containing new PEG chains with negligible metabolic toxicity are more desirable for site-specific PEGylation. Accordingly, for the successful formulation of therapeutic proteins, optimization of the number and distributions of accessible nonessential reactive residues via molecular engineering can be integrated with the design of large-sized PEG derivatives to achieve site-specific PEGylation of all selected/engineered accessible reactive residues.

Structural identification and biological activity of positional isomers of long-acting and mono-PEGylated recombinant human granulocyte colony-stimulating factor with trimeric-structured methoxy polyethylene glycol N-hydroxysuccinimidyl functional group

The individual positional isomers from the mono-PEGylated recombinant human granulocyte colony-stimulating factor (rhG-CSF) were successfully isolated with additional strong cation exchange chromatography using Source 15S. The three isolated individual positional isomers were found to be homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), analytical size exclusion high-performance liquid chromatography (SE-HPLC), and analytical cation exchange HPLC (CIE-HPLC) and were also characterized with respect to site of PEGylation by enzymatic digestion with endoproteinase Lys-C and N-terminal sequencing. In addition, in vitro biological activity was determined by cell proliferation assay. It was determined that the three isolated individual positional isomers were PEGylated at Lys35, Met(N-terminal), and Lys17 of the rhG-CSF molecule with a 23-kDa trimer-structured methoxy polyethylene glycol N-hydroxysuccinimidyl functional group (mPEG-NHS). All individual positional isomers (Lys35-PEGylated rhG-CSF, Met(N-terminal)-PEGylated rhG-CSF, and Lys17-PEGylated rhG-CSF) retained in vitro biological activity and were found to be 18.5%, 37.6%, and 7.1%, respectively, compared with the rhG-CSF molecule. The significantly different in vitro biological activities observed in the individual positional isomers could be presumably due to interference of receptor binding or active sites on the rhG-CSF molecule. In conclusion, the individual positional isomers isolated from the mono-PEGylated rhG-CSF were well characterized with respect to the site of PEGylation involving Lys35, Met(N-terminal), and Lys17. This characterization of the individual positional isomers would be critical to provide a basis for establishing consistency in the manufacturing process.

Enhanced circulation half-life of site-specific PEGylated rhG-CSF: optimization of PEG molecular weight

Recombinant human granulocyte colony stimulating factor (rhG-CSF) and its PEGylated product "mono-PEG20-GCSF" have already been widely used for treatment of all kinds of neutropenia. However, the high required dosage of mono-PEG20-GCSF made it relatively expensive in clinical use. We postulated that an N-terminal site-specific PEGylated rhG-CSF with higher PEG Mw (PEG30 kDa) might be able to achieve longer circulation half-life while retaining its bioactivity, allowing the reduction of dosage for clinical use. rhG-CSF was PEGylated at the N-terminus by 5 kDa, 10 kDa, 20 kDa and 30 kDa methoxy-poly(ethylene glycol)-propionaldehyde (mPEG-ALD), and the four PEGylates were compared with respect to reaction, separation, characterization and also in vivo/in vitro activity, results showed that the mPEG-ALD of higher Mw demonstrated better N-terminal site-specific selectivity, separation purity and yield. The production cost and in vitro activity of mono-PEG30-GCSF and mono-PEG20-GCSF were almost the same, while mono-PEG30-GCSF showed longer in vivo circulation half-life and 60% higher drug bioavailability than mono-PEG20-GCSF. Consequently, mono-PEG30-GCSF shall be administered at a lower dosage than mono-PEG20-GCSF while retaining the same therapeutic efficacy.