"It's obvious once we got into the moderate-severe cases that Prurisol had little to no effect." When exactly did that become obvious?
"Prurisol probably did not work on mild-moderate psoriasis" Probably? Isn't that why you run a trial? Did those mice have magical powers? Were they prettied up for the camera?
"B-ABSSSI on the other hand had a rock solid high-powered phase 2B which was a stellar success. What has prevented a partnership?" Maybe your idea of rock solid isn't universally shared.