The AS treatment guidelines state with respect to sulfasalazine and drugs like sulfasalazine:
"In adults with active AS despite treatment with NSAIDs, we conditionally recommend against treatment with SAARDs (PICO 7; very low- to moderate-quality evidence, depending on the drug; vote 90% agreement). Evidence and rationale. Evidence on the efficacy of SAARDs was based on controlled trials of sulfasalazine
(n 5 8), methotrexate (n 5 3), leflunomide (n 5 1), pamidronate (n 5 1), thalidomide (n 5 1), and apremilast (n 5 1) (see Supplement E: Evidence Report, availableon the Arthritis & Rheumatology web site at http://onlinelibrary.wiley.com/doi/10.1002/art.39298/abstract
). The quality of evidence for critical outcomes was moderate to very low. Sulfasalazine had a small beneficial effect on spinal pain but not on other outcomes, and had a higher risk of side effects than placebo. Although treatment with sulfasalazine did not improve peripheral joint counts, small benefit was seen in a composite measure of peripheral arthritis symptoms. The other medications were tested in small numbers of patients. Trials of methotrexate were limited by use of weekly doses of 10 milligrams or less. Treatment with high-dose pamidronate was associated with improved patient-reported outcomes compared to low-dose pamidronate and deserves further study. Based on a very low to moderate level of evidence of small or no clinical effects, the panel recommended against the use of SAARDs in most patients whose AS remained active despite NSAID
use; treatment with TNFi would be recommended instead (see PICO 6 below). Treatment with sulfasalazine or pamidronate could be considered for patients with contraindications to TNFi or those who decline treatment with TNFi. Sulfasalazine could be considered for those with prominent peripheral arthritis."