JPMorgan analyst Eric Joseph last night upgraded Momenta Pharmaceuticals to Overweight from Neutral with a price target of $30, up from $14. The stock in premarket trading is up 13%, or $3.39, to $28.75. The company on Monday detailed early clinical results from its Phase 1/2 study of M254 in immune thrombocytopenic purpura and the data, albeit early, support "compelling activity / relative potency" compared with conventional intravenous immunoglobulin, Joseph tells investors in a research note. He believes the ITP data, or five of six patients achieving platelet response by standard criteria, give "real clinical credence to the disruptive potential" of M254. Current Momenta share levels under-reflect the commercial potential of M254, says Joseph.