Compound of formula I: or a pharmaceutically acceptable salt thereof, wherein: W is =O, =N-, or =C -; R 1 is an optionally substituted group selected from C 1-6 aliphatic, C 3-7 cycloaliphatic, a 6-10 membered monocyclic or bicyclic aromatic carbocyclic ring, or a 5-10 membered monocyclic or bicyclic saturated, partially unsaturated, or aromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; Q is -N -; each R is independently hydrogen or an optionally substituted C 1-6 aliphatic group, or: two R groups on the same nitrogen are taken together with the nitrogen atom to form a 4-7 membered saturated, partially unsaturated, or aromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; R 2 is an optionally substituted group selected from C 3-7 cycloaliphatic, a 6-10 membered monocyclic or bicyclic aromatic carbocyclic ring, or a 5-10 membered monocyclic or bicyclic saturated, partially unsaturated, or aromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; R 3 is an optionally substituted group selected from C 3-7 cycloaliphatic, a 6-10 membered monocyclic or bicyclic aromatic carbocyclic ring, or a 5-10 membered monocyclic or bicyclic saturated, partially unsaturated, or aromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; n is 0-4; each R 4 is independently selected from halogen, CN, R, OR, SR, N 2, C R, C OR, C N 2, N C R, OC R, SO 2 R, SO 2 N 2, N SO 2 R, or N C N 2 m is 0-2; and each R 5 is independently selected from halogen, CN, R, OR, SR, or N 2 for use in treating or lessening the severity of a disorder in a patient in need thereof, wherein the disorder is selected from Multiple sclerosis, Plaque Psoriasis and Psoriatic arthritis; or wherein the disorder is psoriasis, wherein said compound is to be administered in a composition formulated to comprise said compound in dosages of between 0.1-1 mg, 1-10 mg, 10-25 mg or 25-50 mg. W is =O, =N-, or =C -; R 1 is an optionally substituted group selected from C 1-6 aliphatic, C 3-7 cycloaliphatic, a 6-10 membered monocyclic or bicyclic aromatic carbocyclic ring, or a 5-10 membered monocyclic or bicyclic saturated, partially unsaturated, or aromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; Q is -N -; each R is independently hydrogen or an optionally substituted C 1-6 aliphatic group, or: two R groups on the same nitrogen are taken together with the nitrogen atom to form a 4-7 membered saturated, partially unsaturated, or aromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; R 2 is an optionally substituted group selected from C 3-7 cycloaliphatic, a 6-10 membered monocyclic or bicyclic aromatic carbocyclic ring, or a 5-10 membered monocyclic or bicyclic saturated, partially unsaturated, or aromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; R 3 is an optionally substituted group selected from C 3-7 cycloaliphatic, a 6-10 membered monocyclic or bicyclic aromatic carbocyclic ring, or a 5-10 membered monocyclic or bicyclic saturated, partially unsaturated, or aromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; n is 0-4; each R 4 is independently selected from halogen, CN, R, OR, SR, N 2, C R, C OR, C N 2, N C R, OC R, SO 2 R, SO 2 N 2, N SO 2 R, or N C N 2 m is 0-2; and each R 5 is independently selected from halogen, CN, R, OR, SR, or N 2