Piper Jaffray analyst Edward Tenthoff said that APD334, Arena Pharmaceuticals' (ARNA) S1P1 agonist that showed dose-dependent lowering of lymphocytes in a Phase Ib trial, is now the company's key driver after Arena announced a corporate restructuring and plans to scale back Belviq development. S1P1 agonists have generated significant value, as evidenced by Celgene's (CELG) $7.2B acquisition of Receptos, the analyst noted. Other important pipeline programs include ralinepag, a prostacyclin inhibitor in Phase II trials for pulmonary arterial hypertension, and APD371, a CB2 receptor agonist for pain, noted Tenthoff, who keeps an Overweight rating and $7.50 price target on Arena shares.