 Phase I and Phase II clinical trials have demonstrated that lixivaptan may play an important role in treating hyponatremia and the signs and symptoms of water retention associated with HF, LCWA, and SIADH. Lixivaptan was previously evaluated in disease states characterized by hyponatremia with euvolemia SIADH and hyponatremia combined with fluid overload HF, LCWA. Lixivaptan demonstrated correction in serum sodium concentration together with marked aquaresis in subjects with hyponatremia. 