Arbitration proceedings between Unimed Recife and Unimed Brasil. Concomitant lawsuit seeking the nullity of those proceedings on grounds of bias. Supervening arbitration award. Appeal partially granted to set aside the dismissal of the case with respect to the claim for nullity of the arbitration proceedings, with an order for the action to continue as a rescissory action against the (supervening) arbitration award. Application of the principles of procedural economy and procedural flexibility in view of the "long interim between the arbitration award and the judgment of this appeal," with the possibility of prejudice to the appellant due to the lapse of the limitation period under Article 33. The dismissal of the case is upheld with respect to the remaining claims, which are covered by the arbitration clause of the agreement establishing the Unimed Cooperative System and must be adjudicated through arbitration: