Sprifermin Shows Mixed Results in Knee OA
One-year data reported from proof-of-concept trial
In a new study of patients with osteoarthritis (OA) of the knee, 12 months of treatment with sprifermin (recombinant human fibroblast growth factor 18, Merck Serono) reduced the loss of total femorotibial cartilage thickness compared with placebo-treated knees. This effect, however, was significant in the lateral femorotibial compartment but not in the central femorotibial compartment.
The study results, published in Arthritis & Rheumatology, showed that sprifermin (100 mcg) reduced the loss of cartilage thickness and volume in the total femorotibial joint and in the lateral knee compartment.
The 2010 Global Burden of Disease Study estimated that OA affects 150 million people worldwide, and the American College of Rheumatology has reported that 27 million Americans older than 25 years of age have been diagnosed with the disease.
While OA is the most common cause of physical disability in older adults, studies suggest that the average age at diagnosis is 55 years. No medication or alternative treatment, such as glucosamine or chondroitin, has been shown to have positive effects in preventing or reversing the structural changes of joint damage caused by OA.
“Currently, no structure-modifying treatment has been approved by U.S. or European Union regulatory bodies,” said lead researcher L.S. Lohmander, MD, PhD. “Our trial investigates the safety and efficacy of sprifermin in preventing the loss of cartilage due to OA in the knee.”
The proof-of-concept, double-blind study recruited 192 patients with knee OA who were randomly assigned to receive either single-ascending doses of intra-articular sprifermin or placebo (n = 24) or multiple-ascending doses of sprifermin or placebo (n= 168). Sprifermin was administered at doses of 10, 30, and 100 mcg. The researchers measured cartilage thickness at 6 and 12 months using magnetic resonance imaging (MRI); joint-space width was measured by x-ray; and pain was scored using the Western Ontario and McMaster Universities (WOMAC) OA index.
A total of 168 patients were evaluated for cartilage changes. At 12 months, the researchers found no change in cartilage thickness in the central medial femorotibial compartment in patients treated with sprifermin. However, a reduction in the loss of total and lateral femorotibial cartilage thickness and volume was noted in patients injected with 100 mcg of sprifermin compared with placebo-treated patients. Narrowing of the joint-space width was also reduced in the lateral femorotibial compartment in OA patients who received sprifermin 100 mcg.
The WOMAC pain score was improved in all patients, but less improvement was noted at 12 months in those who received sprifermin 100 mcg compared with those who received placebo.
Lohmander concludes: “While our trial found no reduction in cartilage thickness in the central femorotibial compartment among subjects in the treatment group, dose-dependent reductions in structural changes were found in participants treated with sprifermin.”
The authors found no safety or injection-site issues with sprifermin. They cautioned that additional clinical studies will be needed to replicate their findings and to confirm the optimal dosing.
The study was sponsored by Merck Serono S.A.
Source: Wiley; April 17, 2014.