The partnership with MedImmune, which dates back to 2005, is probably Seattle Genetics’ second most important partnership. On the scientific side, now that MedImmune has been merged with Cambridge Antibody Technology [CAT] to form AstraZeneca’s (AZN) biologics division, Seattle Genetics has a real antibody powerhouse on its side. On the financial side, Seattle Genetics could benefit from another pharma giant on its partner list, equipped with the 8th largest R&D budget in the industry and consequently the ability to support multiple clinical programs simultaneously. Looking at Immunogen’s partnership with Sanofi-Aventis, which has thus far led to 3 clinical programs, is making us hope that AstraZeneca will be to Seattle Genetics, what Sanofi is to Immunogen.
The cooperation with MedImmune originally revolved around one target – EphA2. This intriguing target is highly expressed in numerous solid cancers including breast, prostate and colorectal, which makes the potential opportunity immense. In addition, there is a growing body of scientific evidence that expression of EphA2 is associated with aggressiveness and poor survival, which makes its targeting very reasonable in advanced stages of the disease. The specific targeting of EphA2 looks particularly promising since MedImmune’s scientists discovered that there are several regions within EphA2 which become exposed and consequently accessible for antibodies only on cancer cells.
MedImmune views Epha2 as a very important target. In fact, it has such high hopes for it, that there it is currently evaluating multiple approaches to targeting this promising antigen. One of these approaches is Micromet’s (MITI) Bite (stands for: Bi-Specific T cell Engager) platform, which is being co-developed with Medimmune for several targets, one of which is EphA2. The Bite Platform, a very interesting technology (that deserves an article of its own being so different from other antibody-based platforms) consists of two small antibodies that link between a tumor and specific immune cells in order to manipulate them to attack the tumor. It has demonstrated very impressive potency in mice, and even more impressive results among heavily pre-treated NHL patients, mainly due to the very low doses that showed a clinical effect. The Bite platform hasn’t been evaluated in solid tumors yet, but clinical trials are expected to be announced in the future, one of them is for a Bite agent that targets Epha2. Due to its unique characteristics that present both advantages and disadvantages, it is very hard to predict Bite’s efficacy in these settings. Although some consider Bite an immunotoxin, it differs from immunoconjugates in that it does not contain any drug or toxin payload, so it is reasonable to expect that MedImmune will explore it in parallel to Seattle Genetics’ platform. Although Bite is not necessarily a direct competitor, I bet the folks at Seattle Genetics are following that program closely. Nevertheless, MedImmune seems pretty happy with Seattle Genetics’ platforms, as it has recently licensed Seattle Genetics’ ADC technology for a second undisclosed target.
Author is long SGEN