Skeleton on Horseback (1937)

The "White Plague", a deadly leprosy-like disease that mainly infects people older than 50 years, is ravaging the world. Doctor Galen, a reclusive physician who has devoted his life to the poor, finds a cure. But he refuses to share his cure with the rich and powerful, unless his one condition is met -- eternal peace among nations. Meanwhile, the nation's militaristic leader is preparing to invade a neighboring country. Then the dictator's only close friend, an aristocratic arms manufacturer who is an essential part of his war plans, catches the disease. . .