All CytomX drugs are probodies. That mean prodrugs, drugs that are inactive systemically, but activated locally within the diseased tissue. They use the term "probody" because their drugs are prodrugs linked to an antibody. Here is a simple, yet clear explanation: https://cytomx.com/probody-therapeutics/
What an elegant approach to fighting cancer. This is a big deal. The market capitalization of CytomX indicates Wall Street disagrees. My advice, don't be fooled by the price action. This has a high probability of being a grand slam.