Cell Free Remodeling of Glycosylation of Antibodies

The N-glycosylation profile of a monoclonal antibody (mAb) is a critical quality attribute in relation to its therapeutic application. The control of this profile during biomanufacture is difficult because of the multiple parameters that affect the glycosylation metabolism within the cell and the environment in which the cell is grown. One of the approaches that can be used to produce a preferred glycan profile or a single glycoform is through chemoenzymatic remodeling during the isolation of a mAb. Here we describe protocols that can be utilized to produce preferred glycoforms that include galactosylated, agalactosylated, or sialylated glycoforms following isolation of a mAb. Methods for analysis and assignment of structures of the samples following glycoengineering are also described. Chemoenzymatic modeling of mAb glycans has the potential for scale-up and to be introduced into biomanufacturing of mAbs with higher specific therapeutic activities.

The role of protein hydrolysates in prolonging viability and enhancing antibody production of CHO cells

Four independent mAb-producing CHO cell lines were grown in media supplemented with one of seven protein hydrolysates of animal and plant origin. This generated a 7x4 matrix of replicate cultures which was analysed for viable cell density and mAb productivity. In all cultures, a consistent growth rate was shown in batch culture up to 4 to 5 days. Differences between cultures appeared in the decline phase which was followed up to 7 days beyond the start of the cultures. There was a marginal but significant overall increase (x1.1) in the integral viable cell density (IVCD) in the presence of hydrolysate but a more substantial increase in the cell-specific mAb (qMab) productivity (x1.5). There were individual differences between hydrolysates in terms of enhancement of mAb productivity, the highest being a 166% increase of mAb titre (to 117 mg/L) in batch cultures of CHO-EG2 supplemented with UPcotton hydrolysate. The effect of one of the most active hydrolysates (HP7504) on antibody glycosylation was investigated. This showed no change in the predominant seven glycans produced but a significant increase in the galactosylation and sialylation of some but not all the antibodies. Overall, the animal hydrolysate, Primatone and two cotton-derived hydrolysates provided the most substantial benefit for enhanced productivity. The cotton-based hydrolysates can be viewed as valuable supplements for animal-derived component-free (ADCF) media and as a source for the investigation of chemically defined bioactive components. KEY POINTS: • Protein hydrolysates enhanced both IVCD & qMab; the effect on qMab being consistently greater. • Cotton-based hydrolysates showed high bioactivity and potential for use in serum-free media. • Enhanced galactosylation and sialylation was shown for some of the Mabs tested.

LC-MS characterization of valsartan degradation products and comparison with LC-PDA

abstract Valsartan was submitted to forced degradation under acid hydrolysis condition as prescribed by the ICH. Degraded sample aliquots were separated via HPLC using a Hypersil ODS (C18) column (250 x 4.6 mm i.d., 5 µm). Either photodiode array (PDA) detection or mass spectrometry (MS) full scan monitoring of HPLC runs were used. HPLC-PDA failed to indicate Valsartan degradation under forced acid degradation, showing an insignificant peak area variation and that Valsartan apparently remained pure. HPLC-MS using electrospray ionization (ESI) and total ionic current (TIC) monitoring did not reveal any peak variation either, but inspection of the ESI mass spectra showed the appearance of m/z 306 and m/z 352 ions for the same retention time as that of Valsartan (m/z 436). These ions were identified as being protonated molecules of two co-eluting degradation products formed by hydrolysis. These assignments were confirmed by ESI-MS/MS with direct infusion of the degraded samples. The results showed that the use of selective HPLC-MS is essential for monitoring Valsartan degradation. Efficient HPLC separation coupled to selective and structural diagnostic MS monitoring seems therefore mandatory for comprehensive drug degradation studies, particularly for new drugs and formulations, and for method development.

Severe and refractory myositis in mixed connective tissue disease: a description of a rare case

Mixed connective tissue disease (MCTD) is a rare disease that includes clinical and laboratorial manifestations of systemic lupus erythematosus, scleroderma and polymyositis that is associated with high titers of anti-U1RNP antibodies. In general, muscle involvement is subclinical, usually appearing as an increase in muscle enzyme levels that tends to be a characteristic of the initial phases of the disease. Severe clinical muscle weakness is not observed in this disease. The objective of this study is to report a rare case of a patient who presented a severe onset of myositis characterized by dysphagia, an increase in myopathy and a weakening of the cervical musculature. While there was no response to the administration of an initial dose of corticosteroids, improvement was observed after increasing the dose of corticosteroids, in addition to the initiation of pulse therapy with methylprednisolone accompanied by methotrexate treatment. The authors emphasize that there is only one previously reported case regarding a child with MCTD and severe clinical myopathy on electromyography and muscle biopsy, and they report in this article one adult female patient who presented severe myositis and was refractive to corticotherapy.