The pharmaceutical giant Pfizer Inc., the industry-leading creator of anti-cancer drugs, has reached an agreement to purchase Seagen, one of the pioneers in the field of antibody-drug conjugates (ADCs) at the biotech business based outside of Seattle for $43 billion in cash.

Pfizer is poised to rake in more than $100 billion in 2022 thanks to sales of the Covid-19 vaccine (Comirnaty) and the oral drug Paxlovid (nirmatrelvir-ritonavir). Meanwhile, patent exclusivity for existing Pfizer heavyweights, including blood thinner Eliquis (apixaban) and breast cancer drug Ibrance (palbociclib), is declining. For the acquisition, Pfizer agreed to pay $229 per share, nearly 40% more than Seagen's share price prior to the news of the acquisition.

Sales of the Covid-19 vaccine (Comirnaty) and the oral medicine Paxlovid (nirmatrelvir-ritonavir) are expected to propel Pfizer's revenue to more than $100 billion in 2022. In the meantime, the duration of patent exclusivity for established Pfizer heavyweights like the blood thinner Eliquis (apixaban) and the breast cancer drug Ibrance (palbociclib) is declining. Pfizer has agreed to pay $229 per share for the purchase, which represents an increase of over 40% in comparison to the price of Seagen share price prior to the news of the acquisition.

Most ADCs use a chemical linker to link the antibody to the drug molecule. These drug molecules are highly cytotoxic and can kill cancer cells. These drugs are more targeted than traditional chemotherapy drugs and perform better in terms of efficacy and side effects.

Nine ADCs have been approved since 2019, meaning there are now 15 available in Europe, the US, and Japan (1 in Japan and 14 in the US and EU, but 1 of these drugs has been discontinued for commercial reasons). There are also more than a dozen ADCs in advanced stages of clinical trials and development stages.

"Designing an ADC is an elaborate process that involves careful planning, meticulous execution, and intensive troubleshooting," commented a scientist from Creative Biolabs, a CRO providing ADC development solutions, ranging from ADC antibody screening to ADC manufacturing.

Antibody screening services, including antigen selection, antigen-specific antibody screening, internalizing antibody selection, and proof-of-concept feasibility validation using "anti-Ab ADCs," are conducted at the onset of an ADC development project. A suitable payload drug will be selected and coupled to a linker with the desired releasing mechanism in order to assemble the "chemical warhead" for an ADC, which will then be conjugated to the selected antibody after certain modification or engineering.

After ADC assembly, its biochemical properties (purity, stability, drug-to-antibody ratio, etc.) and in vitro efficacy are adequately evaluated in ADC in vitro analysis, whereas the ADC's pre-clinical pharmacological parameters are evaluated in ADC in vivo analysis prior to clinical evaluation and application.