background is required. Seattle Genetics’ genetically engineered antibody is designed to hit a protein target found on Hodgkin’s lymphoma cells known as CD30. This is a target that’s structurally different from the one hit by one of the best-selling antibody drugs of all time, Roche and Biogen Idec’s rituximab (Rituxan), which is made to hit a protein called CD20. Rituximab, first approved by the FDA in 1997, is a “naked” antibody that zeroes in specifically on cells bearing the CD20 target. The new Seattle Genetics antibody has a similar targeting capability, but adds a tiny dose of a highly potent chemo agent that is supposed to give the antibody even greater knockout punch against the cancer cells. Scientists have tried this approach for decades, with no real success, usually because the toxin would break off from the antibody in the bloodstream, or the toxin just never got properly deposited in the tumor cells.
Now, here’s what the trial was designed to say—and what it doesn’t say.
The trial started in February 2009, after the company and the FDA agreed it was properly designed—through what is known as a Special Protocol Assessment. All patients got the treatment, so none were randomly assigned to a control group—a practice that is often considered the gold standard of medical evidence. By designing the trial this way, Seattle Genetics knew it would have a better chance of recruiting patients quickly, because all patients knew they would get a promising new agent, and not risk a 50-50 chance of getting a placebo or another round of chemo.
Patients were given intravenous infusions of the Seattle Genetics treatment every three weeks, getting as many as 16 total doses. Patients who enrolled had relapsed or refractory (treatment-resistant) Hodgkin’s, they had already undergone autologous stem cell transplants, and all had seen their disease worsen after getting a median of 3.5 prior rounds of therapy. Essentially, these were the sickest of the sick patients with Hodgkin’s, with no good options left. They were a median age of just 31 years old, and had a life expectancy of two to three more years at the time they enrolled in the study.
The main goal of the study was to look
