PRAGUE — Intra-articular injections of autologous conditioned serum reduced symptoms of knee osteoarthritis significantly more than did saline or hyaluronan injections in the therapy's first controlled clinical trial, Dr. Carsten Moser reported at the 2006 World Congress on Osteoarthritis.

“This is a completely different approach to the treatment of osteoarthritis,” said Dr. Moser, a physician at University Hospital Düsseldorf (Germany) and an adviser to the company that markets Orthokine, the product used to condition the serum.

The therapy, originally marketed as IRAP to treat lameness in racehorses, is used by more than 400 physicians in Europe to enhance muscle healing in humans, he said at the meeting, which was sponsored by the Osteoarthritis Research Society International. “It does not require approval in Europe because it involves autologous serum, which is drawn and prepared by the physician,” he said in an interview. The company is currently facing distribution problems in the United States, and it is unclear if the therapy will require FDA approval, he added.

Serum conditioning involves incubation of the patient's venous blood with medical- grade glass beads, he said. Previously published work has shown that this incubation procedure elicits a rapid increase in the serum's synthesis of several anti-inflammatory cytokines (Inflamm. Res. 2003;52:404-7).

“Peripheral blood leukocytes produce elevated amounts of endogenous anti-inflammatory cytokines such as interleukin-1 receptor antagonist,” he said. The conditioned serum is then injected into the affected joint.

The trial involved 345 patients, average age 57 years, with radiologic evidence of knee osteoarthritis and pain greater than 50 points on a 100-point visual analog scale (VAS). After blood was drawn from all patients, they were randomized to intra-articular injections of either autologous conditioned serum (ACS), hyaluronan (HA), or saline twice a week for 3 weeks.

Outcomes were assessed at 7, 13, and 26 weeks after the last injection, using patient-administered outcome instruments of pain measurement including the Western Ontario and McMaster Osteoarthritis index (WOMAC), the VAS, and a health-related quality-of-life measure (SF-8).

“Pain was significantly reduced in all three groups, and quality of life was increased. However, the positive therapeutic responses to ACS were stronger, compared to the other treatment modalities,” Dr. Moser said. “The magnitude of improvement in the ACS group was significantly higher and persisted for months after the last injection. Compared to ACS, the mean reduction in pain was half in the other treatment groups.” He added that adverse events in all groups were confined to localized pain and swelling from the injection (23% of the ACS group, 28% of the saline group, and 38% of the HA group).