Pfizer, Eli Lilly report detailed results from late-stage study of NGF inhibitor tanezumab in osteoarthritis pain

Pfizer and Eli Lilly announced full results from a Phase III study of tanezumab in patients with osteoarthritis (OA) pain, showing that more than half of subjects given the NGF inhibitor experienced a 50 percent or greater reduction in pain. The companies reported in July that the trial met all three co-primary endpoints, with significant improvements in pain, physical function and the patients' overall assessment of their OA, compared to those receiving placebo. 

Results presented at the American College of Rheumatology/Association of Rheumatology for Health Professionals (ACR/ARHP) annual meeting showed that 57.1 percent of patients given a higher dose of tanezumab experienced a 50 percent or greater reduction in pain at week 16, compared to 54.5 percent for the lower dose of the drug and 37.9 percent for placebo.

Meanwhile, physical function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscale, with patients given the high dose of tanezumab experiencing a 3.5 reduction from baseline, versus reductions of 3.2 for the low dose of the drug and 2.6 for placebo. Further, for patient's overall assessment of their OA, patients given the high dose of tanezumab experienced a 0.9 reduction from baseline, compared to reductions of 0.87 for the low dose of the drug and 0.65 for placebo.

"The results demonstrated by tanezumab in this study are particularly meaningful, given that patients had moderate-to-severe pain and were unable to achieve adequate pain relief with other treatment options, including opioids and NSAIDs," remarked Ken Verburg, tanezumab development team leader at Pfizer global product development. Verburg added "our goal is to be able to offer tanezumab as a potential non-opioid treatment option for these patients suffering from osteoarthritis pain."

The study randomised 698 patients with OA of the knee or hip to treatment with tanezumab or placebo administered via two injections eight weeks apart, followed by a 24-week follow-up period. Subjects administered tanezumab received a 2.5 mg dose initially, which was followed either by the same dose or one of 5 mg.

Pfizer and Eli Lilly noted that the most common adverse events were nasopharyngitis, pain in extremity and paresthesia, which all had a higher frequency in patients given tanezumab compared to placebo. The companies indicated that 0.4 percent of patients in the low-dose tanezumab group discontinued treatment due to adverse events, which rose to 1.3 percent in both the high-dose arm and placebo group. Pfizer and Eli Lilly added that there were no cases of osteonecrosis in the study, while rapidly progressive osteoarthritis was seen in tanezumab-treated patients at a frequency of 1.3 percent and was not observed for placebo.

Verburg said the companies are "cautiously optimistic" about the path forward for tanezumab, but more data are still needed, especially from a safety study due to readout next year. The executive noted that with regards to joint safety, "we were hoping to see a little bit better balance between tanezumab and placebo." Verburg added "the numbers are small and one or two events from one treatment group to another could have changed the picture substantially" regarding progressive osteoarthritis.

Late-stage studies of tanezumab are also being conducted in patients with chronic low back pain and cancer pain due to bone metastases, with further results expected in the first half of 2019. Pfizer and Eli Lilly are developing the drug under the terms of a 2013 agreement, with the FDA awarding the compound fast track designation last year for the treatment of chronic pain associated with OA and chronic low back pain.

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