Monoclonal antibody purification by ceramic hydroxyapatite chromatography

Calcium Orthophosphate (CaPO4)-Based Bioceramics: Preparation, Properties, and Applications

Various types of materials have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A short time later, such synthetic biomaterials were called bioceramics. Bioceramics can be prepared from diverse inorganic substances, but this review is limited to calcium orthophosphate (CaPO4)-based formulations only, due to its chemical similarity to mammalian bones and teeth. During the past 50 years, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the CaPO4-based implants would remain biologically stable once incorporated into the skeletal structure or whether they would be resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed, and such formulations became an integrated part of the tissue engineering approach. Now, CaPO4-based scaffolds are designed to induce bone formation and vascularization. These scaffolds are usually porous and harbor various biomolecules and/or cells. Therefore, current biomedical applications of CaPO4-based bioceramics include artificial bone grafts, bone augmentations, maxillofacial reconstruction, spinal fusion, and periodontal disease repairs, as well as bone fillers after tumor surgery. Prospective future applications comprise drug delivery and tissue engineering purposes because CaPO4 appear to be promising carriers of growth factors, bioactive peptides, and various types of cells.

Matrices and Affinity Ligands for Antibody Purification and Corresponding Applications in Radiotherapy

Antibodies have become an important class of biological products in cancer treatments such as radiotherapy. The growing therapeutic applications have driven a demand for high-purity antibodies. Affinity chromatography with a high affinity and specificity has always been utilized to separate antibodies from complex mixtures. Quality chromatographic components (matrices and affinity ligands) have either been found or generated to increase the purity and yield of antibodies. More importantly, some matrices (mainly particles) and affinity ligands (including design protocols) for antibody purification can act as radiosensitizers or carriers for therapeutic radionuclides (or for radiosensitizers) either directly or indirectly to improve the therapeutic efficiency of radiotherapy. This paper provides a brief overview on the matrices and ligands used in affinity chromatography that are involved in antibody purification and emphasizes their applications in radiotherapy to enrich potential approaches for improving the efficacy of radiotherapy.

Trastuzumab in breast cancer treatment: the Era of biosimilars

BACKGROUND

The discovery of trastuzumab as anti-HER2 therapy markedly improved disease control and the survival rates of patients with HER2+ breast cancer. However, as trastuzumab is considered a complex molecule, the cost of production is usually elevated, which significantly affects health budgets and limits the treatment access for patients who live in underdeveloped countries. Recently, trastuzumab production became more accessible and sustainable due to the patents' expiration, allowing biosimilar versions of trastuzumab to be developed.

OBJECTIVE

Our main goal was to shed more light on the uses of biosimilars in breast cancer treatment, emphasizing trastuzumab.

METHOD

An integrative review was carried out in the PubMed, Scielo, Web of Science, and SCOPUS databases using the terms "biosimilar," "breast cancer," "monoclonal antibody," and "trastuzumab." The time range included scientific articles published from 2015 to 2021.

RESULTS AND DISCUSSION

The bibliographic survey showed the complexities in biological medicine manufacturing and how the monoclonal antibody's therapy with trastuzumab improved the patients' life expectancy, revolutionizing HER2+ breast cancer treatment. Nonetheless, despite its benefits, trastuzumab generates certain restrictions, especially from the economic perspective. Trastuzumab biosimilars have high selectivity and rarely cause adverse effects compared to conventional chemotherapy.

CONCLUSION

This study shows that trastuzumab biosimilars improve patients' accessibility to breast cancer treatment through a safe and effective therapy compared to the drug reference.

Current approaches for the purification of antibody-drug conjugates

In the past two decades, antibody-drug conjugates have gained increasing attention because they expand the therapeutic index when compared with that of traditional chemotherapies. Antibody-drug conjugates are highly complex structures consisting of antibodies covalently conjugated with small-molecule cytotoxic drugs. The complex structure of antibody-drug conjugates makes chemistry, manufacturing, and control difficult. In contrast to antibody production, distinct purification methods following conjugation of antibodies with drug-linkers are required for the manufacturing. For process development of antibody drug conjugates, the drug-to-antibody ratio, free drug-linkers, and aggregates are critical quality attributes that must be strictly controlled and removed by appropriate purification techniques. In this review, features of various purification methods used to purify antibody drug conjugates are described and evaluated. The future landscape of the antibody-conjugates field is also discussed briefly.