Who knows why BMRN bought/kinda bought RNA? Who knows why Time bought AOL? Supposedly smart managements make bad decisions and BMRN did this time. In order for FDA to approve drisapersen it will have to overlook obvious safety issues for a chronic condition in kids and somehow believe in an efficacy conclusion based upon some major data mining that makes some pretty outlandish assumptions, i.e. you’ll finally see the beneficial effect after years of therapy which hasn’t happened yet.
As for IP we’re talking about two entirely different chemistries that are dependent on different mechanisms of action that have dramatically different stabilities, time to be cleared from the blood stream, number of bases paired, off target effects, sequence specificity, targeting success rates, side effects, MTD, you name it.
PMOs are more stable. Are longer, pair more bases. Have a higher affinity for the RNA. Are charge neutral. Work by steric blocking and are not RNAase H dependent like drisapersen. Don’t bind to a broad range of proteins like drispaersen. Have expected inadvertent targets of around 0.4 versus 3517 for a comparable S-DNA. PMOs don’t degrade the target RNA as the phosphorothioates do. PMOs block the target RNA activity until the RNA degrades naturally and releases the PMO. PMOs can be dosed much higher. Phosphorothioates have a plasma half life of 19 to 56 days! PMOs, on the other hand, have a plasma half life of 2 to 6 hours. BMRN can’t patent the RNA and neither can SRPT. The drugs and the way they work are obviously different.
And PPMD may have some pull but they ain’t gonna be able to get FDA to change their whole raison d’etre just to approve drisapersen.