SAN DIEGO, CA—Patients with hip or knee osteoarthritis who received subcutaneous tanezumab reported improvements in pain and physical function at all doses studied, results presented at the 2013 ACR/ARHP Annual Meeting have shown.

Tanezumab 2.5mg and 5mg were better tolerated than tanezumab 10mg, reported Leslie Tive, PhD, Senior Director at Pfizer Inc, New York, NY, and colleagues.

They randomized 678 patients with moderate to severe knee or hip osteoarthritis to tanezumab 2.5mg (n=230), 5mg (n=222), or 10mg (n=226) administered by subcutaneous injection every 8 weeks.

“Efficacy analyses included change from baseline in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain and Physical Function subscales, Patient’s Global Assessment of Osteoarthritis (PGAO), and percentage of patients with ≥30%, ≥50%, ≥70%, and ≥90% improvement in WOMAC Pain,” they noted. “Safety assessments included adverse event (AE) documentation, physical and neurological examinations, and laboratory tests.”

Patients received from 1 to 7 doses of tanezumab. Mean study treatment duration was 180 days for tanezumab 2.5mg; 191 days for the 5mg dose; and 187 days for the 10mg dose. The tanezumab 5mg and 10mg doses resulted in similar improvements from baseline at Weeks 8 and 16 in WOMAC Pain, Physical Function, and PGAO; improvements were greater than with tanezumab 2.5mg.

At Weeks 8 and 16, more patients had ≥30%, ≥50%, ≥70%, and ≥90% improvement in WOMAC Pain with tanezumab 10mg and 5mg than that observed with tanezumab 2.5mg.

The overall incidence of AEs was 80.1% with tanezumab 10mg, 976.1% with 5mg, and 68.7% with 2.5mg. The most frequently reported AEs were arthralgia, injection site reaction, and paresthesia.

“Osteonecrosis was reported as an AE in 4 patients (1.8%) treated with tanezumab 10mg, 4 patients (1.8%) in the tanezumab 5mg group, and 1 patient (0.4%) in the tanezumab 2.5mg group,” Dr. Tive noted. “Thirty-four patients had an all-cause total joint replacement. Of these, 22 (64.7%) events inclusive of the 9 cases of osteonecrosis were subsequently adjudicated by a blinded external adjudication committee and none were adjudicated to primary osteonecrosis.”

Across groups, at the most recent assessment, the percentage of patients with no new or worsened neurological examination abnormality ranged from 82% to 88%.

The study was discontinued prematurely due to a U.S. Food and Drug Administration partial clinical hold on the use of tanezumab in non-cancer pain studies.