this invention relates to methods of treatment of hypersensitivity conditions such as asthma and other allergic conditions , and especially to treatment of these conditions with cyclic peptidic and peptidomimetic compounds which have the ability to modulate the activity of g protein - coupled receptors . the compounds preferably act as antagonists of the c 5 a receptor , and are active against c 5 a receptors on polymorphonuclear leukocytes and macrophages . particularly preferred compounds for use in the methods of the invention are disclosed .