Abstract: A method of inhibition of cellular and molecular level biological interactions which are dependent on RGD interactions is disclosed. The method comprises administering a compound of the formula IH.sub.2 N--C(.dbd.NH)--NH--CH.sub.2 --A--CH.sub.2 --CO.sub.2 H (I)and pharmaceutically acceptable salts thereof, wherein A is a chain of 9 atoms selected from the group consisting of: ##STR1## wherein each of x, n and m is at least 1; in chains (i) and (ii) n is at most 6; in chains (iii) and (iv) the sum of x+n+m is 5; and the sum of n+m is 4 in chain (v) and 3 in chain (vi).

Abstract: Non-peptidic RXD analogues are provided that inhibit biological cellular and molecular interactions which are dependent on RXD recognition, wherein X is one of the amino acid residues G, E, Y, A or F. In particular, RGD surrogates are provided having no sequence of .alpha.-natural amino acids and comprising a guanidino and a carboxyl terminal groups spaced by a chain of 11 atoms, at least 5 of which are carbon atoms. The compounds inhibit cell adhesion and are useful for the treatment of several pathological disorders, e.g., thrombosis, autoimmune diseases, metastasis, allergy, host-graft reactions and inhibition of scar tissue formation.