Arbitration proceedings between Unimed Recife and Unimed Brasil. Concurrent lawsuit seeking the nullity of those proceedings, on grounds of bias, and other claims. 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 that the action continue as a rescissory action against the (supervening) arbitration award. Application of the principles of procedural economy and the principle of procedural flexibility or substancial compliance doctrine, 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 by means of arbitration: