Two subcutaneous dosages of the nerve growth factor–inhibitor tanezumab showed significant benefits in patients with osteoarthritic joint pain in a multicenter, randomized, phase 3 trial of 698 patients run primarily at U.S. centers.
The 16-week responses to two subcutaneous injections with tanezumab spaced 8 weeks apart showed statistically significant improvements in pain, physical function, and patient global self assessment, compared with placebo, the primary endpoints for the study, Pfizer and Lilly jointly reported. The two companies together are developing tanezumab for an indication for osteoarthritic pain, as well as for chronic lower back pain and pain from cancer metastases.
The company announcement said that patients showed good tolerance to the tanezumab treatments, with no new safety signals and no osteonecrosis seen. About 1% of patients on tanezumab stopped treatment because of an adverse effect, and less than 1.5% of patients on the drug had progressive osteoarthritis during treatment, compared with no patients in the placebo group.
The study enrolled patients at any one of 98 centers in the United States, Puerto Rico, or Canada with confirmed moderate or severe osteoarthritis of the knee or hip that either produced pain refractory to conventional pain medications or involved patients unable to take these medications. The researchers randomized patients to receive two 2.5-mg doses of tanezumab, a 2.5-mg dose followed 8 weeks later by a 5-mg dose, or two placebo doses. The primary outcomes were changes from baseline when measured 16 weeks after the start of treatment in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale, the WOMAC physical function subscale, and patient’s global assessment of osteoarthritis. Both of the tested tanezumab regimens produced statistically significant improvements in each of the three measures, compared with the placebo control patients, the companies reported.
Tanezumab is a humanized monoclonal antibody that binds to and inhibits nerve growth factor. This inhibition may prevent pain signals from reaching the spinal cord and brain, according to the companies’ report. In June 2017, the two companies announced that development of tanezumab had received “Fast Track” designation from the Food and Drug Administration for the indications of treating chronic osteoarthritic pain and chronic lower back pain.