Background/objective: The objective of this study was to investigate the safety and efficacy of subcutaneous (SC) and intravenous (IV) tanezumab administration in osteoarthritis (OA) patients.

Materials and methods: Study 1027 (NCT01089725), a placebo-controlled trial, evaluated the efficacy of SC tanezumab (ie, 2.5, 5, and 10 mg) and the therapeutic equivalence of 10 mg tanezumab given subcutaneously versus intravenously every 8 weeks in the symptomatic treatment of OA. Coprimary endpoints were: change from baseline in Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) Pain and Physical Function indices, and Patient's Global Assessment (PGA) of OA. Study 1043 (NCT00994890) was a long-term, noncontrolled safety study of tanezumab (ie, 2.5, 5, and 10 mg) subcutaneously administered every 8 weeks. Both studies were discontinued prematurely due to a US Food and Drug Administration partial clinical hold.

Results: Due to the clinical hold, Study 1027 was underpowered, and no statistical analyses were performed. Mean (standard error [SE]) change from baseline to week 8 in WOMAC Pain in tanezumab groups ranged from -3.59 (0.26) to -3.89 (0.32), versus -2.74 (0.25) with placebo. Mean (SE) change from baseline to week 8 in WOMAC Physical Function ranged from -3.13 (0.25) to -3.51 (0.28) with tanezumab and was -2.26 (0.24) with placebo. PGA mean (SE) change from baseline to week 8 ranged from -0.90 (0.11) to -1.08 (0.12) with tanezumab and was -0.78 (0.10) with placebo. Similar effectiveness was associated with tanezumab in Study 1043. Few patients in either study (1.4%-5.2%) discontinued due to adverse events. Five patients required total joint replacements in Study 1027 (placebo, n=2 [2.8%]; tanezumab 2.5 mg, n=3 [4.1%]) and 34 patients in Study 1043 (tanezumab 2.5 mg, n=11 [4.8%]; tanezumab 5 mg, n=8 [3.6%]; tanezumab 10 mg, n=15 [6.6%]).

Conclusion: Preliminary results show similar efficacy and safety for both SC and IV administration of tanezumab based on the direct comparisons reported here and indirect comparisons with published results, confirming pharmacokinetic/pharmacodynamic modeling predictions.