The most frequent adverse events were upper respiratory tract infection ( placebo 6 [ 7 % ] patients vs ALD403 7 [ 9 % ] patients ) , urinary tract infection ( 4 [ 5 % ] vs 1 [ 1 % ] ) , fatigue ( 3 [ 4 % ] vs 3 [ 4 % ] ) , back pain ( 4 [ 5 % ] vs 3 [ 4 % ] ) , arthralgia ( 4 [ 5 % ] vs 1 [ 1 % ] ) , and nausea and vomiting ( 2 [ 2 % ] vs 3 [ 4 % ] ) .