Amgen and Roche end EPO patent infringement dispute

March 25, 2016

Results were measured in two ways. First, a "blinded" dermatologist measured the severity of a patient's psoriasis lesions weekly using the Psoriasis Severity Scale (PSS), a standard tool used to track the redness, hardening and thickening of skin. The second measure was whether a patient experienced a "relapse" in lesion severity, defined arbitrarily as a return to a PSS score within two units of a patient's initial score.

In terms of the overall PSS severity scores, results were mixed. The Stanford study site found no group differences in PSS scores that could be attributed to the different treatment regimens. Ader believes that elevated baseline PSS scores in the randomly selected Dose Control subjects at Stanford might have obscured the differences between the dose control and partial reinforcement groups. For instance, results could have been influenced by differences in the amount of sun patients were exposed to in Upstate New York and California (ultraviolet light is an established treatment for psoriasis).

In Rochester, there were no differences between the PSS values of the Partial Reinforcement and Dose Control groups at the point in the study where experimental treatment began. In this case, partial reinforcement brought about a greater reduction in lesion severity during the experimental period than continuous reinforcement with the same cumulative amount of drug.

The relapse results were clearer. Four of 18 patients (22.2 percent) in the 100 percent reinforcement group (full dose all the time) relapsed within the eight-week experimental period. Among patients treated with a full dose of drug, but one half or one quarter of the time (50 or 25 percent reinforcement schedule), four of 15 patients (26.7 percent) relapsed. Thus, the incidence of relapse did not differ substantially between patients receiving a full dose of drug all the time and those treated under the partial reinforcement schedules, researchers said. In contrast, eight of the 13 patients (61.5 percent) in the dose control group who received active drug each time, but not the full does, relapsed in the same period of time.

Thus, the incidence of relapse in the partial reinforcement group (26.7 percent) was significantly less than in dose control patients (61.5 percent) that received the same cumulative amount of drug. Further studies are underway, and others are planned, to confirm the effect, answer the questions raised and explore the effect in other autoimmune diseases.

The study was conducted jointly by the Departments of Psychiatry and Dermatology within the School of Medicine & Dentistry at the University of Rochester and the Stanford University School of Medicine. Along with Ader, the study was authored in Rochester by Mary Gail Mercurio, James Walton and Deborra James. Leading the effort at Stanford were David Fiorentino, Alexa Kimball, Michael Davis and Valerie Ojha. The study was funded by a grant from the National Institute of Arthritis, Metabolic and Skin Disease (NIAMS), part of the National Institutes of Health (NIH).

"The pharmaceutical industry may choose to ignore the conditioning component of drug treatment regimens," Ader said. "Alternatively, they may now consider exploring ways to exploit conditioning in the design of drug treatment protocols, especially in chronic conditions where patients acquire conditioned responses over time. I believe industry will eventually support this approach because it promises to increase safety and reduce production costs."

Source: University of Rochester Medical Center