Johnson & Johnson has entered into a definitive agreement to acquire Ambrx Biopharma, Inc., a clinical-stage biopharmaceutical company with a synthetic biology technology platform to design and develop next-generation antibody drug conjugates (ADCs), for a total equity value of approximately $2.0 billion.   Ambrx is advancing a focused portfolio of clinical and preclinical programs designed to optimize efficacy and safety of its candidate therapeutics in multiple cancer indications, includ...