This invention relates to pyrazol pyridine derivatives of formula (I) wherein R1 is a radical of the formula −O—SO2—R3 in which R3 is optionally substituted C1—6—alkyl, optionally substituted C3—8—cycloalkyl, or optionally substituted phenyl; R2 is H, optionally substituted C1—6—alkyl —CO—or optionally substituted C1—6—alkyl—SO2— ; as well as salts, stereoisomers, tautomers, and hydrates thereof. Pharmaceutical compositions containing these materials and methods of using them in medical treatment are also described and claimed.