Kadcyla is an antibody-drug conjugate (ADC) used to treat HER2-positive breast cancer. The manufacturing process for Kadcyla involves several downstream processes [1][3].

The first step is the production of the monoclonal antibody, trastuzumab, which is done using mammalian cell culture technology [3]. The next step involves the conjugation of trastuzumab with a cytotoxic drug, DM1, using a linker molecule [1]. This process results in the formation of the ADC, Kadcyla [1][3].

The final downstream process involves the purification of Kadcyla. This process is crucial as it removes any impurities that may have been introduced during the conjugation process [3]. The purification process involves several chromatography steps, including protein A affinity chromatography, ion exchange chromatography, and size exclusion chromatography [3].

Once the purification process is complete, the final product is tested for potency, purity, and stability [3]. The regulatory authorities require that the potency of Kadcyla be determined using a validated bioassay [3].

In conclusion, the downstream processes for the manufacturing of Kadcyla involve the production of the monoclonal antibody, conjugation of the antibody with a cytotoxic drug, and purification of the ADC. The final product is then tested for potency, purity, and stability before being approved for use in treating HER2-positive breast cancer patients [1][3].

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/KADCYLA
[3] https://bioprocessintl.com/analytical/product-characterization/kadcycla-adc-potency-regulatory-and-bioprocessing-concerns-of-antibody-drug-conjugates/