A Manhattan appellate court has thrown out a lawsuit by a plaintiff’s firm that claimed it was shortchanged by another firm to which it had referred clients for a massive lawsuit against the maker of withdrawn diet drug fen-phen.

Parker & Waichman, a Great Neck, N.Y., personal injury firm, sued Manhattan’s Napoli Kaiser & Bern, now known as Napoli Bern, in 2001 over the latter firm’s allocation of funds paid by American Home Products, now known as Wyeth, to settle a suit on behalf of more than 5,000 former fen-phen (dexfenfluramine) users. The Food and Drug Administration ordered a recall of the drug in 1997 after studies linked it to heart valve damage.