Pump may reduce drug's potency.

Interleukin-2 (IL-2), a powerful therapeutic protein that has shown promising clinical results in the treatment of cancer and AIDS, is degraded significantly by contact with materials in the pump and tubing that often are used to deliver it, according to Todd Przybycien, associate professor of chemical engineering, Rensselaer Polytechnic Institute. Even a brief interaction between IL-2 and the tubing or pump causes a physical change in the protein that reduces its biological activity.

IL-2 usually is delivered intravenously or directed to the spot needing treatment either by an implantable pump or an externally wearable pump together with an implanted catheter tube. When dosages are being calculated, it is assumed that the protein remains physically stable during delivery.

Przybycien and his colleagues analyzed the nature and extent of interactions of a commercial IL-2 formulation with a portable infusion pump with a catheter tubing system. They found loss of biological activity by approximately 90% after 24...