Headquartered in Exton, Pennsylvania, USA, Therakos is a Johnson & Johnson company which was established in order to foster advances in the extracorporeal management of disease. The company has undertaken extensive research into photoimmune therapy which led to the development of photopheresis, also known as extracorporeal photoimmune therapy, an approach to the management of disease using photoactivatable agents and light.

The company's principal product, the UVAR XTS Photopheresis System, is an integrated device for photopheresis and is approved by the FDA and in many other countries around the world for the palliative treatment of the skin manifestations of cutaneous T-cell lymphoma. In December 2006, the US Centers for Medicare & Medicaid Services also expanded insurance coverage for extracorporeal photopheresis for patients with acute cardiac allograft rejection whose disease is refractory to standard immunosuppressive drug treatment and for patients with chronic graft-verses-host disease whose disease is refractory to standard immunosuppressive drug treatment. The Therakos therapy has been used in over half a million treatments in the US and Europe.

Therakos is also conducting clinical trials with the aim of seeking FDA approval for a number of new disease indications for photopheresis, including emerging indications in the field of immune-mediated inflammatory diseases and disorders such as the prevention and treatment of graft-versus-host disease.

Therakos works closely with other J&J companies in the development of photopheresis, including Cordis, Janssen Italy, Johnson & Johnson Medical France, Johnson & Johnson Medical Germany and Johnson & Johnson Medical UK.