Niti-S Duodenal Comfort Stent is indicated for the palliative treatment of pyloric or duodenal obstructions caused by malignant neoplasms. Niti-S Colonic Comfort Stent is indicated for the palliative treatment of colorectal strictures produced by malignant neoplasms and to relieve large bowel obstruction prior to colectomy in patients with malignant strictures.
Device Story
Niti-S Duodenal and Colonic Comfort Stents are self-expanding nitinol wire mesh prostheses; used for palliative treatment of malignant gastrointestinal obstructions. Stents are loaded into a co-axial delivery system; advanced over a 0.035-inch guidewire via endoscope into duodenum or colon. Deployment occurs by pulling the outer sheath of the delivery system under fluoroscopic and/or endoscopic guidance. Device provides mechanical patency to obstructed lumens; benefits patients by relieving obstruction and symptoms. Used in clinical settings by physicians; no electrical or software components.
Clinical Evidence
No clinical data. Substantial equivalence supported by bench testing, including packaging strength, sterility verification, deployment accuracy, deployment force, dimensional testing, tensile strength, trackability, visualization, and repositioning force tests.
Technological Characteristics
Self-expanding nitinol wire mesh stent; radiopaque markers. Delivery system: co-axial tube type, 10 Fr profile, 220 cm length. Compatible with 0.035 in guidewire. Sterilization: Ethylene Oxide (EO). No electrical components or software.
Indications for Use
Indicated for palliative treatment of pyloric or duodenal obstructions due to malignant neoplasms, and colorectal strictures due to malignant neoplasms or large bowel obstruction prior to colectomy.
Regulatory Classification
Identification
An esophageal prosthesis is a rigid, flexible, or expandable tubular device made of a plastic, metal, or polymeric material that is intended to be implanted to restore the structure and/or function of the esophagus. The metal esophageal prosthesis may be uncovered or covered with a polymeric material. This device may also include a device delivery system.
Special Controls
The special control for this device is FDA's “Guidance for the Content of Premarket Notification Submissions for Esophageal and Tracheal Prostheses.”
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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food & Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is a blue square with the letters FDA in white. To the right of the blue square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.
March 31, 2025
Taewoong Medical Co., Ltd. % Matthew Krueger Principal Consultant Biologics Consulting Group 100 Daingerfield Road Suite 400 Alexandria, Virginia 22314
Re: K250663
Trade/Device Name: Niti-S Duodenal Comfort Stent Niti-S Colonic Comfort Stent Regulation Number: 21 CFR 878.3610 Regulation Name: Esophageal Prosthesis Regulatory Class: Class II Product Code: MUM, MQR Dated: March 5, 2025 Received: March 5, 2025
Dear Matthew Krueger:
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
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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).
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.
All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advicecomprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
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 medical devices and radiation-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
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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 (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
# Anthony Lee -S
Anthony Lee, Ph.D., M.B.A. Assistant Director DHT3A: Division of Renal, Gastrointestinal, Obesity, and Transplant Devices OHT3: Office of Gastrorenal, ObGyn, General Hospital, and Urology Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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## Indications for Use
Form Approved: OMB No. 0910-0120 Expiration Date: 07/31/2026 See PRA Statement below.
Submission Number (if known)
K250663
Device Name
Niti-S Duodenal Comfort Stent, Niti-S Colonic Comfort Stent
Indications for Use (Describe)
Niti-S Duodenal Comfort Stent is indicated for the palliative treatment of pyloric or duodenal obstructions caused by malignant neoplasms.
Niti-S Colonic Comfort Stent is indicated for the palliative treatment of colorectal strictures produced by malignant neoplasms and to relieve large bowel obstruction prior to colectomy in patients with malignant strictures.
Type of Use (Select one or both, as applicable)
> Prescription Use (Part 21 CFR 801 Subpart D)
Over-The-Counter Use (21 CFR 801 Subpart C)
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#### 1. SUBMITTER INFORMATION
| Applicant: | Taewoong Medical |
|------------|----------------------------------------------------------------------------------|
| Contact: | Yongjin Jeff Kim |
| Phone: | +82 70 4649 1543 |
| Email: | jinjeff@stent.net |
| Address | 14, Gojeong-ro, Wolgot-myeon, Gimpo-si, Gyeonggi-do, 10022,<br>Republic of Korea |
#### 2. CORRESPONDENT INFORMATION
| Contact: | Matthew Krueger |
|----------|----------------------------|
| Title: | Principal Consultant |
| Firm: | Biologics Consulting Group |
#### 3. DATE PREPARED: MARCH 4, 2025
#### 4. DEVICE INFORMATION
| Device Name: | Niti-S Duodenal Comfort Stent<br>Niti-S Colonic Comfort Stent |
|--------------------|---------------------------------------------------------------------------|
| Common Name: | Duodenal stent; colonic stent |
| Regulation Number: | 21 CFR 878.3610 |
| Regulation Name: | Esophageal Prosthesis |
| Product Code: | MUM (Niti-S Duodenal Comfort Stent)<br>MQR (Niti-S Colonic Comfort Stent) |
| Regulatory Class: | Class II |
#### 5. PREDICATE DEVICE INFORMATION
| Primary Predicate: | Niti-S Duodenal Comfort Stent; |
|--------------------|--------------------------------|
| Device Name: | Niti-S Colonic Comfort Stent |
| 510(k) Number: | K223067 |
| Manufacturer: | Taewoong Medical |
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Reference Device Name: Esophageal TTS Stent K240522 510(k) Number: Manufacturer: Taewoong Medical
The predicate device has not been subject to a design related recall.
#### 6. DEVICE DESCRIPTION
The Niti-S Duodenal Comfort Stent and Niti-S Colonic Comfort Stent consist of an implantable metallic stent and an introducer system.
The stent is made of nitinol wire and is designed as a flexible, fine mesh tubular prosthesis with several radiopaque markers. The Niti-S Duodenal Comfort Stent has a diameter of 22 mm, while the Niti-S Colonic Comfort Stent is available in diameters of 22 mm and 24 mm. Both stent types are available in lengths of 60 mm, 80 mm, 100 mm, and 120 mm.
The stent delivery system accommodates a 0.035 in (0.89 mm) guidewire. It is advanced over the guidewire and passed through an endoscope into the duodenum or colon. Fluoroscopy is recommended to ensure accurate device placement.
#### 7. INDICATIONS FOR USE
Niti-S Duodenal Comfort Stent is indicated for the palliative treatment of pyloric or duodenal obstructions caused by malignant neoplasms.
Niti-S Colonic Comfort Stent is indicated for the palliative treatment of colorectal strictures produced by malignant neoplasms and to relieve large bowel obstruction prior to colectomy in patients with malignant strictures.
#### COMPARISON OF INTENDED USE 8.
The Indications for Use are for the Niti-S Duodenal Comfort Stent and Niti-S Colonic Comfort Stent are unchanged from the cleared predicate devise (K223067). The purpose of this 510(k) is to align the design of the subject stent delivery systems (SDSs) with those of the Esophageal TTS Stent (K240522). These changes included slight component modifications and some material changes. The principle of operation of the updated Niti-S Duodenal Comfort Stent and Niti-S Colonic Comfort Stent SDSs remains unchanged. Fluoroscopic and/or endoscopic guidance is still used for SDS positioning and the stent deployment procedure is the same overall.
### 9. COMPARISON OF TECHNOLOGICAL CHARACTERISTICS WITH THE REFERENCE DEVICE
The table below compares the new Niti-S Duodenal and Colonic Comfort SDSs that are being proposed for use with the subject device and compares it to the Esophageal TTS SDSs. The new
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subject SDSs are based off the design of the Esophageal TTS SDSs and is largely identical other than the differences noted below.
| Table 1: | Niti-S Duodenal Comfort Stent and Niti-S Colonic Comfort Stent SDS<br>Technological Comparison to Reference Device |
|----------|--------------------------------------------------------------------------------------------------------------------|
|----------|--------------------------------------------------------------------------------------------------------------------|
| | Subject Device- | Reference Device |
|-------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| | | K240522 |
| Trade/Device<br>Name | Niti-S Duodenal Comfort Stent<br>Niti-S Colonic Comfort Stent | Esophageal TTS Stent |
| Regulation<br>Number | 21 CFR 878.3610 | 21 CFR 878.3610 |
| Expansion<br>method | The stent is loaded into the distal part of the<br>delivery device and expanded in the body by<br>pulling the outer sheath of the delivery device.<br>The stent is made of self-expanding nitinol. | The stent is loaded into the distal part of the<br>delivery device and expanded in the body by<br>pulling the outer sheath of the delivery<br>device. The stent is made of self-expanding<br>nitinol. |
| Method of<br>introduction | Endoscopic | Endoscopic |
| Sterility | EO Sterilization | EO Sterilization |
| Delivery<br>system photo | Image: Delivery system photo for Subject Device<br>Co-axial tube type | Image: Delivery system photo for Reference Device<br>Co-axial tube type |
| Delivery<br>system length | 220 cm (endoscopic) | 180 cm (endoscopic)<br>220 cm (endoscopic) |
| Delivery<br>system<br>profile | 10 Fr (3.3 mm) | 10.5 Fr (3.5 mm) |
| Guidewire | 0.035 in (0.89 mm) | 0.035 in (0.89 mm)<br>0.038 in (0.97 mm) |
#### 10. SUMMARY OF NON-CLINICAL PERFORMANCE TESTING
## Biocompatibility Testing
The stent material of the subject device is identical to that of the Niti-S Duodenal Comfort Stent and Niti-S Colonic Comfort Stent cleared in K223067, including its formulation, processing, and sterilization, with no additional chemicals (e.g., plasticizers, fillers, additives, cleaning agents, mold release agents) introduced.
Similarly, the SDS material of the subject device is identical to the Esophageal TTS Stent cleared in K240522 by Taewoong Medical, including its formulation, processing, and sterilization, with no additional chemicals added.
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Therefore, additional biocompatibility testing for the Stent Delivery System is not required.
## Electrical Safetv
Not applicable. The subject device contains no electrical components, generates no electrical emissions, and uses no electrical energy of any type.
## Electromagnetic Compatibility (EMC)
Not applicable. The subject device contains no electrical components, generates no electrical emissions, and uses no electrical energy of any type.
## Software
Not applicable. The subject device contains no software.
## Performance Testing
Additional performance testing was conducted to demonstrate that the device meets its design requirements and performs as intended. Samples were aged to reflect the stent and SDS shelf-life and the following tests/analyses were performed.
- Packaging strength and dye penetration
- Sterility verification ●
- o Deployment accuracy test
- Deployment force test ●
- Dimensional test ●
- Tensile strength test (SDS) ●
- Trackability and visualization test
- Repositioning force test ●
#### CONCLUSION 11.
The results of the performance testing described above demonstrate that the Niti-S Duodenal Comfort Stent and Niti-S Colonic Comfort Stent are as safe and effective as the predicate device and supports a determination of substantial equivalence.
Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.