wherein X is carbon;

Y is nitrogen;

W is carbon or nitrogen;

U and Z each independently, is CR², NR¹³, nitrogen, oxygen, sulfur, C═O or C═S;

R² is

(i) hydrogen,

(ii) C1-8 alkyl,

(iii) C2-8 alkenyl,

(iv) C2-8 alkynyl,

(v) halogen atom,

(vi) CF₃,

(vii) cyano,

(viii) nitro,

(ix) NR⁹R¹⁰ in which R⁹ and R¹⁰ each independently,

(i) hydrogen,

(ii) C1-4 alkyl,

(iii) C3-10 mono- or bi-carbocyclic ring,

(iv) 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) or

(v) C1-4 alkyl substituted by C3-10 mono- or bi-carbocyclic ring or 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s),

(x) OR¹¹ in which R¹¹ is

(i) hydrogen,

(ii) C1-4 alkyl,

(iii) C5-6 carbocyclic ring,

(iv) 5 or 6 membered heterocyclic ring containing 1-2 of nitrogen(s), 1 of oxygen and/or 1 of sulfur or

(v) C1-4 alkyl substituted by C5-6 carbocyclic ring or 5 or 6 membered heterocyclic ring containing 1-2 of nitrogen(s), 1 of oxygen and/or 1 of sulfur,

(xi) SH,

(xii) S(O)_nR¹² in which n is 0, 1 or 2, R¹² is

(i) C1-4 alkyl,

(ii) C5-6 carbocyclic ring,

(iii) 5 or 6 membered heterocyclic ring containing 1-2 of nitrogen(s), 1 of oxygen and/or 1 of sulfur or

(iv) C1-4 alkyl substituted by C5-6 carbocyclic ring or 5 or 6 membered heterocyclic ring containing 1-2 of nitrogen(s), 1 of oxygen and/or 1 of sulfur,

(xiii) COR¹¹,

(xiv) COOR¹¹,

(xv) CONR⁹R¹⁰,

(xvi) C3-10 mono-or bi-carbocyclic ring,

(xvii) 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) or

(xviii) C1-4 alkyl substituted by 1-2 of substitutes selected from halogen atom, CF₃, OCF₃, cyano, nitro, NR⁹R¹⁰, OR¹¹, ═N—OR¹¹, SH, S(O)_nR¹², COR¹¹, COOR¹¹, CONR⁹R¹⁰, C3-10mono- or bi- carbocyclic ring and 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s),

R¹³ is

(i) hydrogen,

(ii) C1-4 alkyl,

(iii) C2-4 alkenyl,

(iv) C2-4 alkynyl,

(v) C3-10 mono- or bi-carbocyclic ring,

(vi) 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) or

(vii) C1-4 alkyl substituted by C3-10 mono- or bi-carbocyclic ring or 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s),

is a single bond or a double bond,

R¹ is

(i) C1-8 alkyl which is unsubstituted or substituted by 1-5 of R¹⁴,

(ii) C2-8 alkenyl which is unsubstituted or substituted by 1-5 of R¹⁴,

(iii) C2-8 alkynyl which is unsubstituted or substituted by 1-5 of R¹⁴,

(iv) NR⁴R⁵ in which R⁴ and R⁵ each independently,

(i) hydrogen,

(ii) C1-15 alkyl which is unsubstituted or substituted by 1-5 of R¹⁷,

(iii) C2-15 alkenyl which is unsubstituted or substituted by 1-5 of R¹⁷,

(iv) C2-15 alkynyl which is unsubstituted or substituted by 1-5 of R¹⁷,

(v) C3-15 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R¹⁸,

(vi) 3-15 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁸,

(v) OR⁶ in which R⁶ is

(i) hydrogen,

(ii) C 1-10 alkyl,

(iii) C2-10 alkenyl,

(iv) C2-10 alkynyl,

(v) C3-15 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R¹⁸,

(vi) 3-15 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁸,

(vii) C1-4 alkyl substituted by 1-2 of substitutes selected from halogen atom, CF₃, OCF₃, cyano, nitro, NR⁹R¹⁰, OR¹¹, ═N—OR¹¹, SH, S(O)nR¹², COR¹¹, COOR¹¹, CONR⁹R¹⁰, C3-10 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R¹⁸, and 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁸,

(vi) SH,

(vii) S(O)nR⁷ in which n is as hereinbefore defined, R⁷ is

(i) C1-8 alkyl,

(ii) C3-10 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R¹⁸,

(iii) 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁸,

(iv) C1-4 alkyl substituted by C3-10 mono- or bi-carbocyclic ring, which is unsubstituted or substituted by 1-5 of R¹⁸ or 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁸,

(viii) COR⁶,

(ix) COOR⁶,

(x) CONR⁴R⁵,

(xi) NR⁸COR^6a in which R^6a is

(i) hydrogen,

(ii) C1-10 alkyl,

(iii) C2-10 alkenyl,

(iv) C2-10 alkynyl or

(v) C1-4 alkyl substituted by 1-2 of substitutes selected from halogen atom, CF₃, OCF₃, cyano, nitro, NR⁹R¹⁰, OR^11a, ═N—R¹¹, SH, S(O)nR¹², COR¹¹, COOR¹¹ and CONR⁹R¹⁰,

(xii) NR⁸COOR⁶ in which R⁶ is as hereinbefore defined, R⁸ is

(i) hydrogen,

(ii) C1-8 alkyl,

(iii) C2-8 alkenyl,

(iv) C2-8 alkynyl,

(v) C3-10 mono- or bi-carbocycic ring which is unsubstituted or substituted by 1-5 of R¹⁸,

(vi) 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁸ or

(vii) C1-4 alkyl substituted by 1-2 of substitutes selected from halogen atom, CF₃, OCF₃, cyano, nitro, NR⁹R¹⁰,═N—OR¹¹, SH, S(O)nR¹², COR¹¹,COOR¹¹, CONR⁹R¹⁰, C3-10 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R¹⁸, and 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁸,

(xiii) NR⁸CONR⁴R⁵,

(xiv) C3-15 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R¹⁵ or

(xv) 3-15 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁵,

R^11a is (i) hydrogen, (ii) C1-4 alkyl or (iii) C1-4 alkyl substituted by C5-6 carbocyclic ring or 5 or 6 membered heterocyclic ring containing 1-2 of nitrogen(s), 1 of oxygen and/or 1 of sulfur,

R¹⁴ is (a) halogen atom, (b) CF₃, (c) OCF₃, (d) cyano, (e) nitro, (f) NR⁴R⁵, (g) OR⁶, (h) ═N—OR⁶, (j) SH, (k) S(O)ⁿR⁷, (l) COR⁶, (m) COOR⁶, (n) CONR⁴⁵, (o) NR⁸COR⁶, (p) NR⁸COOR⁶, (q) NR⁸CONR⁴R⁵, (r) C3-15 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R¹⁵ or (s) 3-15 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R¹⁵,

R¹⁵ is (a) C1-8 alkyl, (b) C2-8 alkenyl, (c) C2-8 alkynyl, (d) C1-4 alkoxy(C1-4)alkyl, (e) halogen atom, (f) CF₃, (g) OCF₃, (h) cyano, (j) nitro, (k) NR⁴R⁵, (l) OR⁶, (m) SH, (n) S(O)_nR⁷, (o) COR⁶, (p) COOR⁶, (q) CONR⁴R⁵, (r) NR⁸COR⁶, (s) NR⁸COOR⁶, (t) NR⁸CONR⁴R⁵, (u) C3-10 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R²⁰, (v) 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R²⁰ or (w) C1-4 alkyl substituted by 1-2 of substitutes selected from halogen atom, CF₃, OCF₃, cyano, nitro, NR⁴R⁵, OR⁶, ═N—OR⁶, SH, S(O)_nR⁷, COR⁶,COOR⁶, CONR⁴R⁵,NR⁸COR⁶,NR⁸COOR⁶, NR⁸CONR⁴R⁵, C3-10 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R²⁰, and 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R²⁰,

R¹⁷ is (a) halogen atom, (b) CF₃, (c) OCF₃, (d) cyano, (e) nitro, (f) NR⁹R¹⁰, (g) OR^11a, (h) ═N—OR¹¹, (j) SH, (k) S(O)_nR¹², (l) COR¹¹, (m) COOR¹¹, (n) CONR⁹R¹⁰, (o) NR⁸COR¹¹, (p) NR⁸COOR¹¹, (q) NR⁸CONR⁹R¹⁰, (r) C3-15 mono- or bi-carbocyclic ring which is unsubstituted or substituted by 1-5 of R^18a or (s) 3-15 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) which is unsubstituted or substituted by 1-5 of R^18a,

R¹⁸ is (a) C1-4 alkyl, (b) C2-4 alkenyl, (c) C2-4 alkynyl, (d) halogen atom, (e) CF₃, (f) OCF₃, (g) cyano, (h) nitro, (j) SH, (k) S(O)_nR¹², (l) NR⁹R¹⁰, (m) OR¹¹, (n) COR¹¹, (o) COOR¹¹, (p) CONR⁹R¹⁰, (q) C5-6 carbocyclic ring, (r) 5 or 6 membered heterocyclic ring containing 1-2 of nitrogen(s), 1 of oxygen and/or 1 of sulfur or (s) C1-4 alkyl substituted by C5-6 carbocyclic ring or 5 or 6 membered heterocyclic ring containing 1-2 of nitrogen(s), 1 of oxygen and/or 1 of sulfur,

R^18a is (a) C1-4 alkyl, (b) C2-4 alkenyl, (c) C2-4 alkynyl, (d) halogen atom, (e) CF₃, (f) OCF₃, (g) cyano, (h) nitro, (j) SH, (k) S(O)_nR¹², (l) NR⁹R¹⁰, (m) OR^11a, (n) COR¹¹, (o) COOR¹¹ or (p) CONR⁹R¹⁰,

R¹⁹ is C1-4 alkyl, C1-4 alkoxy, halogen atom, CF₃, OCF₃, cyano, nitro, amino, NH(C1-4 alkyl) or N(C1-4 alkyl)₂,

R³ is (i) C5-10 mono- or bi-carbocyclic ring substituted by 1-5 of R¹⁶ or

(ii) 5-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s) substituted by 1-5 of R¹⁶,

R¹⁶ is(a)C1-8 alkyl,

(b) C2-8 alkenyl,

(c) C2-8 alkynyl,

(d) halogen atom,

(e) CF₃,

(f) OCF₃,

(g) cyano,

(h) nitro,

(j) NR⁹R¹⁰,

(k) OR¹¹,

(l) SH,

(m) S(O) _nR¹²,

(n) COR¹¹,

(o) COOR¹¹,

(p) CONR⁹R¹⁰,

(q) NR⁸COR¹¹,

(r) NR⁸COOR¹¹,

(s) NR⁸CONR⁹R¹⁰,

(t) C3-10 mono- or bi-carbocyclic ring,

(u) 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s)

(v) C1-4 alkyl substituted by 1-2 of substitutes selected from halogen atom, CF₃, OCF₃, cyano, nitro, NR⁹R¹⁰, OR¹¹, ═N-OR¹¹, SH, S(O) _nR¹², COR¹¹, COOR¹¹, CONR⁹R¹⁰, NR⁸COR¹¹, NR⁸COOR¹¹, NR⁸CONR⁹R¹⁰, C3-10 mono- or bi-carbocyclic ring, and 3-10 membered mono-or bi-heterocyclic ring containing 1-4 of nitrogen(s), 1-2 of oxygen(s) and/or 1-2 of sulfur(s),

with the proviso that (1) when each of X and W is carbon, each of Y and Z is nitrogen, U is CR² and R¹ is OR⁶, then R³ is not phenyl substituted by 1 of halogen atom, phenyl substituted by 1 of trifluoromethyl and phenyl substituted by trifluoromethyl and nitro, (2) when each of X and Z is carbon and each of U and W is nitrogen, then R³ is C5-10 mono- or bi-carbocyclic ring substituted by 1-5 of R¹⁶; and (3) when R¹⁶ is S(O)_nR¹² and R¹² is (iii), R¹² is a 5 or 6 membered heterocyclic ring containing 1-2 nitrogen, a 5 or 6 membered heterocyclic ring containing 1 of oxygen and/or a 5 membered heterocyclic ring containing 1 of sulfur;

a pharmaceutically acceptable salt thereof or a hydrate thereof.