Patent ID: 8518890

Claim:
A method for treating prostate cancer, which comprises administering an effective amount of an LHRH receptor agonist or antagonist or a salt thereof to a mammal in need thereof, and after a prostate cancer cell has become highly sensitive to androgen, administering an effective amount of an androgen receptor agonist or a salt thereof, wherein the LHRH receptor agonist is a peptide of the formula: (Pyr)Glu-R 1 -Trp-Ser-R 2 -R 3 -R 4 -Arg-Pro-R 5 (I) wherein R 1 is His, Tyr, Trp or p-NH 2 -Phe; R 2 is Tyr or Phe; R 3 is Gly or a D type amino acid residue optionally having substituent(s); R 4 is Leu, Ile or Nle; and R 5 is Gly-NH—R 6 , wherein R 6 is a hydrogen atom or an alkyl group optionally having a hydroxyl group, NH—R 7 , wherein R 7 is a hydrogen atom, an amino group, an alkyl group optionally having a hydroxyl group, or —NH—CO—NH 2 ; wherein the D type amino acid residue for R 3 is a-D-amino acid having up to 9 carbon atoms, which is selected from the group consisting of D-Leu, Ile, Nle, Val, Nval, Abu, Phe, Phg, Ser, Thr, Met, Ala, Trp, and a-Aibu; the substituent for R 3 is selected from the group consisting of tert-butyl, tert-butoxy, tert-butoxycarbonyl, methyl, dimethyl, trimethyl, 2-naphthyl, indolyl-3-yl, 2-methylindolyl, and benzyl-imidazo-2-yl; and the alkyl group for R 6 or R 7 is a C 1-4 alkyl group selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl or a salt thereof; the LHRH receptor antagonist is selected from the group consisting of abarelix, ganirelix, cetrorelix, 5-(N-benzyl-N-methylaminomethyl)-1-(2,6-difluorobenzyl)-6-[4-(3-methoxyureido)phenyl]-3-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione, 5-(N-benzyl-N-methylaminomethyl)-1-(2,6-difluorobenzyl)-6-[4-(3-ethylureido)phenyl]-3-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione, and 5-(N-benzyl-N-methylaminomethyl)-1-(2,6-difluorobenzyl)-6-[4-(3-ethylureido)phenyl]-3-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione hydrochloride; and the androgen receptor agonist is a steroidal androgen receptor agonist selected from the group consisting of dehydroepiandrosterone, testosterone, dihydrotestosterone, androstenedione, Mestanolone, Oxymesterone, Methandrostenolone, Fluoxymesterone, Chlorotestosterone acetate, Methenolone acetate, Oxymetholone, Stanozolol, Furazabol, Oxandrolone, 19-Nortestosterone, Norethandrolone, Ethylestrenol and Norbolethone, or a salt thereof.