Biotech Values

[mcbio]

I don't know the potentcy of Letaris but it doesn't bind to the B nor does (did) Encysives drug Thelin (Sitaxentan) which was pulled for safety (I forget what tox but sure could easily google).

RTRX recently updated their corporate presentation and claims RE-021 is one of only two ERAs (zibotentan being the other) advanced into the clinic that does not bind the "negative feedback" ET-B receptor. I think I mentioned before the slide 19 that shows less safety issues in the clinic for RE-021 compared to avosentan and darusentan (much less peripheral edema).

Having a letter from someone at FDA may be nice but for ETA's we've seen SPA's meet and not get approval (Encysive first 2 times around).

Fair point.

And why doesn't/didn't GSK/Pfizer/Gilead pursue?

If it is just truly zibotentan that is selective for ET-A among ERAs advanced into the clinic, perhaps AZN just wasn't aware of the rationale for an ET-A selective ERA against FSGS? And for any others not advanced into the clinic that are selective for ET-A, perhaps the same thought applies?