The investigational injectable filler 2.5% polyacrylamide hydrogel (AquamidR) is as effective and well tolerated as hyaluronic acid (HA, RestylaneR), for the correction of nasolabial folds, according to pivotal data released here at the 2009 American Society of Dermatologic Surgery (ASDS) meeting.
In fact, the results showed the polyacrylamide hydrogel was as effective as HA at six months on the widely validated Wrinkle Assessment Scale (WAS), the study’s primary endpoint. In addition, efficacy was maintained at the 12-month follow-up evaluation.
“Our results demonstrate that polyacrylamide hydrogel shows strong potential as a permanent soft tissue filler,” Rhoda Narins, MD, Clinical professor of Dermatology at New York University School of Medicine in New York City and Director of the Dermatology Surgery and Laser Center of New York, said.
Because polyacrylamide hydrogel is non-biodegradable and does not migrate, it is expected that efficacy will continue over a longer period than occurs with HA, she added.
Dr. Narins and colleagues compared the efficacy and safety of polyacrylamide hydrogel to HA in 315 men and women who presented for bilateral soft tissue augmentation of the nasal labial folds and had a WAS of 3 or 4.
The primary efficacy measure was the mean change in WAS scores at six months.
The study found that the average WAS improvement at six months in the polyacrylamide hydrogel group was 1.8 points versus 2.0 in the HA group.
“This means that the improvement in both groups was more than triple the minimum clinically relevant difference of 0.5 points,” Dr. Narins observed.
Efficacy was maintained through the 12-month post-treatment follow-up, with an average 1.7-point improvement in both treatment groups.
The type and frequency of treatment-related side effects were similar with the two fillers. Side effects were usually mild and transient and occurred as a result of the injection procedure.
One patient developed an infection that was thought to be related to the investigational treatment and resolved within 24 days.
The data also suggest a benefit for polyacrylamide hydrogel beyond its favorable safety and efficacy, Dr. Narins said. Because the filler is non-biodegradable and not resorbed, the patient dos not require periodic re-injections. “Thus, the patient avoids the risk of bruising, infection and other potential effects that may result from additional injections,” she said.
Finally, the New York city-based dermatologist noted that only about 25 percent of patients had previously received a soft tissue filler, which may reflect increasing interest among patients to seek a longlasting soft tissue filler and avoid surgery.
While the results using polyacrylamide hydrogel are promising, longer follow-up is needed to establish whether the favorable effects seen at one year hold up over the long-term, she added. In Europe, five-year data support the efficacy and safety of polyacrylamide hydrogel for correction of nasolabial folds and for multiple other facial indications.
Written by Jill Stein
Jill Stein is a Paris-based freelance medical writer.
jillstein03(at)gmail.com