Silk Voice (SMI-04)

K240919 · Sofregen Medical · MIX · May 3, 2024 · Ear, Nose, Throat

Device Facts

• Record ID: K240919
• Device Name: Silk Voice (SMI-04)
• Applicant: Sofregen Medical
• Product Code: MIX · Ear, Nose, Throat
• Decision Date: May 3, 2024
• Decision: SESE
• Submission Type: Special
• Regulation: 21 CFR 874.3620
• Device Class: Class 2
• Attributes: Therapeutic

Intended Use

Silk Voice® is indicated for vocal fold medialization and vocal fold insufficiency that may be improved by injection of a soft tissue bulking agent. Silk Voice® injection augments the size of the displaced or deformed vocal fold so that it may meet the opposing fold at the midline for improved phonation. Vocal fold insufficiency associated with serious aspiration difficulties may be an urgent indication.

Device Story

Silk Voice (SMI-04) is a sterile, injectable, bioabsorbable implant for vocal fold medialization. It consists of porous regenerated silk fibroin particles suspended in cross-linked hyaluronic acid (HA) gel. The device is supplied in a prefilled syringe with a catheter for endoscopic delivery. ENT specialists inject the material into the vocal fold tissue; the HA gel acts as a carrier, while the silk particles remain at the site to provide a scaffold for local tissue infiltration. This process provides immediate volume augmentation and long-term restoration of the vocal fold, allowing it to meet the opposing fold at the midline. The device is used in clinical settings by physicians to improve patient phonation and reduce aspiration risks.

Clinical Evidence

Bench testing only. No clinical data presented. Performance testing included particle size/circularity analysis, rheometry, extrusion force, HA fragment testing, particle concentration, residual crosslinker content, pH, endotoxin levels, and catheter integrity (leak/tensile strength). Sterilization validation confirmed SAL 10-6. Biocompatibility is supported by data from the predicate device (K180631) per ISO 10993 requirements.

Technological Characteristics

Implant: Porous regenerated silk fibroin particles in cross-linked hyaluronic acid (HA) carrier. Particle size: 250 ± 50 μm. Delivery: Prefilled syringe with flexible catheter for endoscopic injection. Sterilization: Steam and EtO (SAL 10-6). Biocompatibility: ISO 10993 compliant. Storage: Ambient temperature.

Indications for Use

Indicated for patients with vocal fold insufficiency or displacement requiring medialization to improve phonation or address aspiration difficulties.

Regulatory Classification

Identification

Ear, nose, and throat synthetic polymer material is a device material that is intended to be implanted for use as a space-occupying substance in the reconstructive surgery of the head and neck. The device is used, for example, in augmentation rhinoplasty and in tissue defect closures in the esophagus. The device is shaped and formed by the suregon to conform to the patient's needs. This generic type of device is made of material such as polyamide mesh or foil and porous polyethylene.

Predicate Devices

• Sofregen's Silk Voice (K180631)

Submission Summary (Full Text)

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May 3, 2024

Sofregen Medical Vivian Ruan Quality and Regulatory Manager 175 Crossing Blvd, Suite 510 Framingham, Massachusetts 01702

Re: K240919

Trade/Device Name: Silk Voice (SMI-04) Regulation Number: 21 CFR 874.3620 Regulation Name: Ear, Nose, And Throat Synthetic Polymer Material Regulatory Class: Class II Product Code: MIX Dated: April 3, 2024 Received: April 3, 2024

Dear Vivian Ruan:

We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

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Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email ([e-mail]) or phone [phone] or 301-796-7100).

Sincerely,

# Joyce C. Lin -S

for Shu-Chen Peng, Ph.D. Assistant Director DHT1B: Division of Dental and ENT Devices OHT1: Office of Ophthalmic, Anesthesia, Respiratory, ENT and Dental Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

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## Indications for Use

510(k) Number (if known) K240919

Device Name Silk Voice (SMI-04)

### Indications for Use (Describe)

Silk Voice® is indicated for vocal fold medialization and vocal fold insufficiency that may be improved by injection of a soft tissue bulking agent. Silk Voice® injection augments the size of the displaced or deformed vocal fold so that it may meet the opposing fold at the midline for improved phonation. Vocal fold insufficiency associated with serious aspiration difficulties may be an urgent indication.

| Type of Use (Select one or both, as applicable) | |
|-----------------------------------------------------------------------------------|----------------------------------------------------------------------------------|
| <div> <span> ☑ Prescription Use (Part 21 CFR 801 Subpart D) </span> </div> | <div> <span> ☐ Over-The-Counter Use (21 CFR 801 Subpart C) </span> </div> |

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In accordance with 21 CFR 807.87(h) and 21 CFR 807.92, the 510(k) Summary for the Silk Voice Vocal Cord Medialization System is provided below.

#### SUBMITTER 1.

Sofregen Medical, Inc. 175 Crossing Blvd. Suite 510 Framingham, MA 01702

Contact Person: Vivian Ruan Phone: [phone] Email: [e-mail] Date Prepared: 01May2024

#### DEVICE 2.

Name of Device: Silk Voice Common Name: System, Vocal Cord Medialization Classification Regulation: 21 CFR 874.3620 Regulatory Class: II Product Code: MIX Panel: Ear, Nose, and Throat

#### 3. PREDICATE DEVICE

Predicate Device: Sofregen's Silk Voice (K180631)

#### DEVICE DESCRIPTION 4.

Silk Voice® is a sterile, non-pyrogenic, cohesive implant provided in a prefilled syringe and is a ready to use product. Silk Voice is comprised of porous bioabsorbable silk particles suspended in an isotonic, aqueous formulation of cross-linked, high molecular weight hyaluronic acid (HA). The crosslinked HA gel acts as a carrier for the silk particles to facilitate delivery. The main component of Silk Voice is silk particles, manufactured exclusively from regenerated silk fibroin protein, isolated from purified silk fibers. When injected, Silk Voice provides immediate volume augmentation to the vocal fold tissue. The porous particles remain at the site of implantation, providing a scaffold for local tissue infiltration. This cellular infiltrated silk scaffold provides longterm restoration and augmentation.

Silk Voice prefilled syringes are provided in a kit with a catheter, that is designed for endoscopic delivery to the vocal fold. The catheter accessory provided in the kit is specifically designed for delivery of injectable materials into tissue during endoscopic procedures.

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#### INDICATIONS FOR USE ਟ.

Silk Voice® is indicated for vocal fold medialization and vocal fold insufficiency that may be improved by injection of a soft tissue bulking agent. Silk Voice® injection augments the size of the displaced or deformed vocal fold so that it may meet the opposing fold at the midline for improved phonation. Vocal fold insufficiency associated with serious aspiration difficulties may be an urgent indication.

| | Subject Device –<br>Sofregen's Silk Voice<br>(Formulation SMI-04) | Predicate Device –<br>Sofregen's Silk Voice<br>(K180631) |
|------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------|
| Classification<br>Regulation | 874.3620 | Same |
| Product Code | MIX | Same |
| Intended Use | Vocal fold augmentation | Same |
| Indication for Use | Silk Voice is indicated for vocal fold<br>medialization and vocal fold insufficiency<br>that may be improved by injection of a soft<br>tissue bulking agent. Silk Voice injection<br>augments the size of the displaced or<br>deformed vocal fold so that it may meet the<br>opposing vocal fold at the midline for<br>improved phonation. Vocal fold<br>insufficiency associated with serious<br>aspiration difficulties may be an urgent<br>indication. | Same |
| Intended User | ENT Specialists | Same |
| Material<br>Composition | Silk particles suspended in a cross-linked,<br>aqueous formulation of HA | Same |
| Particle Size | $250 \pm 50 \mu m$ in diameter | $380 \pm 46 \mu m$ in diameter |
| Delivery Method | Injection via flexible catheter with needle,<br>for endoscope delivery | Same |
| Delivery Device | Prefilled syringe | Same |
| Implant location | Vocal fold | Same |
| Implant duration | Long-term (>6 mo) | Same |
| Sterility | Provided sterile, SAL 10-6 | Same |
| Stability | Ambient temperature storage | Same |
| Biocompatibility | Biocompatible when injected into soft<br>tissues | Same |

#### 6. SUBSTANTIAL EQUIVALENCE

The change to the silk particle size does not affect the safety or effectiveness assessment of the Silk Voice product and the subject device is substantially equivalent to the predicate device.

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#### 7. PERFORMANCE TESTING

#### Shelf-Life Testing 7.1.

Shelf-life testing (device and packaging) was performed to support labeled expiration dating for Silk Voice®.

#### 7.2. Bench Testing

All bench testing passed the acceptance criteria. The bench testing demonstrated that Silk Voice® delivery system meets pre-established design input requirements for its intended use.

Additional bench tests were performed to support a determination of substantial equivalence between the subject device and the predicate device.

- Particle size and circularity analysis ●
- Rheometry
- Extrusion force ●
- HA fragment test ●
- Particle concentration
- Residual Crosslinker Content ●
- . pH
- Endotoxin
- Catheter leak test ●
- Catheter tensile strength ●

Sterilization validation for the steam sterilization cycle and the EtO sterilization cycle were conducted and SAL of 10-6 was demonstrated.

Biocompatibility test results of the predicate device submitted as part of the original submission (K180631) continue to support that Silk Voice® meets the requirements of ISO 10993 for its intended use.

#### 8. CONCLUSION

Based on the same indications for use (and intended use), device functionality, usage, and performance, the subject Silk Voice® formulation is substantially equivalent to the predicate device (K180631).