A Prospective, Randomized, Double-blinded, Controlled, Split-face, Non-inferiority Clinical Investigation Comparing the Safety and Performance of RefillHA Solid With Hydryalix Ultra Deep Lidocaine for the Correction of Moderate-to-severe Nasolabial Folds.

This study will be a prospective, randomized, controlled, monocentric, double blind (evaluator/s and subject) within subject (split-face) non-inferiority clinical study. 40 Subjects will be randomized to be treated with RefillHA Solid in the NLF on one side of the face and comparator product in the NLF on the other side of the face. The side of the face for each product will be randomly assigned. The investigator performing the evaluations and the subject will be blinded to the treatment assignment. Injections of the study products will be performed by an unblinded Treating Investigator (TI).

At Visit 1 (considered baseline if no touch-up performed) eligible subjects, following signing informed consent, will receive injection of RefillHA Solid into left or right NLF, and injection of the control study device into the contralateral NLF (Initial treatment). for a given subject, the RefillHA Solid and control devices to be injected at the same depth between mid to deep dermis, and with the same technique, to be determined at the TI's discretion. The injected volume will be chosen by the TI and depend on the depth of wrinkle to be corrected. The minimum volume into a single NLF per injection session is 0.5 mL and the maximum volume is 2.5 mL, irrespective of the device.

At Visit 2, after 4 weeks from baseline, additional NLF correction with the study devices will be provided, if, per treating investigator's opinion, optimal correction was not achieved (touch-up treatment, considered baseline if performed). Only the NLF requiring touch-up will be treated using the same device as originally injected.

All subjects are scheduled to return for follow-up examinations at W4, W12, W24, W36 and W52 (Visits 3 to 7, respectively) after final treatment.

Subjects will be offered Early Re-Treatment at W24 or W36 (optional retreatment in case of facial asymmetry or if at least one NLF had returned to baseline level). Furthermore, Re-Treatment will be offered to all subjects attending the study visit in W52. Any Re-Treatment will be performed with the RefillHA Solid implant formulation used at the initial treatment, irrespective of the side of face treated.

Inclusion criteria

• Men or women of any race, 18 years of age or older.
• The presence of moderate to severe bilateral NLFs each with WSRS score of 3 or 4.
• NLFs of the same WSRS grade on the left and right sides of the face.
• Willing and able to read, understand and sign the informed consent.
• Willing to adhere to the protocol and to comply with the requirements of the entire investigation (ability to attend all the planned investigation visits according to the time limits included and report events and concomitant medication for the entire duration of investigation).
• Agree not to undergo other treatments or cosmetic procedures in the treatment area during the study, such as botulinum toxin, hyaluronic acid injections, facial laser treatments, fat injections, any other permanent or semi-permanent facial dermal fillers.
• Female subjects of childbearing potential must have a negative urine pregnancy test and must adopt an appropriate method of contraception for the entire duration of investigation.

Exclusion criteria

• Pregnant (as determined by a urine pregnancy test at the screening visit) or lactating women.
• Prior treatment (i.e., other permanent or biodegradable injectable fillers or surgical correction such as a face-lift, etc.) within 3 months prior to entry into the study or planned to undergo such treatment during the study.
• Previous treatment with permanent implants (e.g., silicone) in the area to be treated.
• Subjects who are currently or recently treated with laser, ultrasound or peeling, and who have not fully recovered from these treatments.
• Presence of active inflammation, infection, or unhealed wound of the face, such as acne, herpes, dermatitis, scaring etc.
• Presence of varices in the area to be treated.
• History of hypertrophic scarring.
• Metabolic or endocrine serious diseases (e.g., uncontrolled diabetes or diabetes complications), anaphylaxis, severe allergies, immune disorders affecting the skin or other local or systemic concomitant diseases that may interfere with healing.
• Current neoplastic (including skin cancer) and/or immunodepressive diseases.
• Known hypocoagulability state.
• Have received anti-coagulation, anti-platelet, or thrombolytic medications (e.g., warfarin), anti- inflammatory drugs (NSAIDs such as aspirin, ibuprofen), or other substances known to prolong time of coagulation from a week before treatment. A wash-out period of a week is allowed.
• Use of narcotic agents, antineoplastics, immunosuppressants or any other agent that may interfere with wound healing in the months before the screening visit.
• History of severe allergic/anaphylactic reactions or multiple allergies.
• Subject, who has a condition or is in a situation that, in the investigator's opinion, may put the subject at significant risk, or may significantly interfere with the patient's participation in the study or with protocol evaluation parameters.
• Subjects considered to be unsuitable to participate, in the investigator's opinion, for any other reason.
• Subjects with known allergy or hypersensitivity to at least one component of any of the study medical devices.