FDA Backs Cartiva Implant for Osteoarthritis in the MTP Joint

Troy Brown, RN

April 21, 2016

The US Food and Drug Administration's (FDA's) Orthopaedic and Rehabilitation Devices Panel of the Medical Devices Advisory Committee voted yesterday to recommend premarket approval of the Cartiva Synthetic Cartilage Implant for use in patients with degenerative or posttraumatic arthritis in the first metatarsophalangeal (MTP) joint in the presence of good bone stock along with the following clinical conditions: hallux valgus or hallux limitus, hallux rigidus, and an unstable or painful metatarsophalangeal joint.

The panel voted that the device is safe (10 yes, 2 no) and effective (9 yes, 3 no), and that the benefits of the implant outweigh the risks (8 yes, 2 no, 2 abstain).

"I think this has potential promise. I'm a big fan of minimally invasive treatment, and this may serve as a useful adjunct to treatment of MTP arthritis," temporary voting panel member John B. Kelly IV, MD, from the University of Pennsylvania, Philadelphia, said.

"To the extent that we know the risks, I think they've been reasonably mitigated. I think there may be risks that we don't know yet, and you can't mitigate them, but overall, from what I saw, the benefits outweigh the risks," voting panel member Jeremy Gilbert, PhD, from Syracuse University, New York, explained.

The MTP joint is the most common site for osteoarthritis in the forefoot. Osteoarthritis in the MTP joint can result from trauma, repetitive microtrauma, severe bunion deformities (hallux valgus), and recurrent hallux deformity after surgery. The Cartiva implant is a molded cylindrical device containing polyvinyl alcohol and saline that is implanted into the metatarsal head in the first MTP joint via press-fit implantation. The implant is approved in Europe, Canada, and Brazil.

Pivotal Trial

The vote follows a discussion of data from MOTION (A Prospective, Randomized, Non-Inferiority Study to Evaluate the Safety and Effectiveness of Cartiva Synthetic Cartilage Implant in the Treatment of First Metatarsophalangeal Joint Osteoarthritis as Compared to a Control).

The study was a multicenter pivotal trial that included 236 patients and was conducted at six sites in Canada and six sites in the United Kingdom. The researchers randomly assigned participants in a 2:1 ratio to undergo implantation of the Cartiva device or arthrodesis/fusion. Neither the patients nor the investigators were blinded. The primary endpoint was a single composite for pain, function, and safety. The researchers evaluated safety through 24 months and effectiveness at 12 months. The FDA requested a post hoc effectiveness assessment at 24 months, which the researchers conducted.

Safety

At least one adverse event was reported in 69.1% of patients in the Cartiva group and 72% of patients in the arthrodesis group during the 24 months. The incidence rate of serious device-related adverse events was 7.2% in the Cartiva group and 4.0% in the arthrodesis group. Adverse events included procedural pain, device pain, and arthralgia.

A total of 14 (9.2%) patients in the Cartiva group underwent subsequent removal of the implant, and four (8%) patients in the arthrodesis group underwent subsequent removal of screws implanted during the procedure.

"I think there was safety demonstrated in this scientifically valid study," Dr Gilbert said.

Effectiveness

"The device did improve patients' pain, [and] did improve their outcome. I do think it demonstrated effectiveness; maybe it wasn't better than or maybe it was almost inferior to the fusion, but I think there was efficacy," Dr Gilbert said.

The researchers used a visual analog scale to assess pain. Both treatment groups experienced clinically meaningful reductions in pain during the study; visual analog scale scores were lower in the Cartiva group through week 2 but were higher from week 6 through month 24.

Both treatment groups had clinically meaningful improvements in mean Foot and Ankle Mobility Sports (FAAM sports) subscale and Foot and Ankle Mobility Activities of Daily Living (FAAM ADL) subscale scores during the study.

The Cartiva group had higher FAAM ADL and the FAAM sports scores through week 6, but the arthrodesis group had better FAAM ADL scores and FAAM sports scores from 3 through 24 months.

"Postapproval Studies Are Mandatory"

The panel would like to see postapproval studies that follow the patients for 5 years.

"I think we don't know [if the risks outweigh the benefits,] and I think we need a much longer follow-up to make sure," voting panel member Maureen Finnegan, MD, from the University of Texas Southwestern Medical Center, Dallas, said. Dr Finnegan voted not to recommend premarket approval of the implant.

"Postapproval studies are mandatory to assess for increasing failure rate over time and the possibility of particulate wear debris," voting panel member S. Raymond Golish, MD, PhD, MBA, a physician in private practice in Jupiter, Florida, said.

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