Alnylam Pharmaceuticals' Givosiran over the weekend met the primary endpoint with a 74% reduction in annualized composite porphyria attacks over six months in a Phase III study, Piper Jaffray analyst Edward Tenthoff tells investors in a research note. Half of treated patients remained attack-free for the study period, the analyst points out. Further, the three serious adverse events do not concern him as he believes "these are explained by study imbalance and underlying disease characteristics." Tenthoff expects launch in the U.S. and Europe in 2020. He estimate sales of $15M in 2020, growing to $629M by 2025. This will be Alnylam's second RNAi drug approval, says the analyst. Tenthoff reiterates an Overweight rating on Alnylam with a $142 price target.