Applications / Meniscal Repair
A recombinant protein that bonds in a wet field and drives cell proliferation — an augmentation for tears that sutures alone cannot heal.
Development stage: the meniscus data on this page come from preclinical (animal) studies conducted with the Department of Orthopaedic Surgery, Kagawa University. FP-121 is an investigational material and has not been approved as a medical device or regenerative medical product. Efficacy and safety in humans have not been established.
The Social Challenge
The meniscus distributes load across the knee. A knee that loses it moves toward wear, and mobility, participation and independence are stripped away in sequence.
One of the leading causes of disability on earth
DALYs attributable to knee OA, 2019
Long-term follow-up
Downstream treatment cost
Knee OA, Dutch workforce
Sources: GBD-based knee OA analysis, 2019 — 364.6M prevalent cases and 11.53M DALYs worldwide · Snoeker BAM et al., J Orthop Sports Phys Ther 2013 — 4-fold long-term OA risk · ClinicoEconomics and Outcomes Research 2021 — US knee OA treatment cost · BMC Musculoskelet Disord 2022 — 186-day mean sick-leave episode.
The Unmet Need
If the tissue is resected
had developed tibiofemoral osteoarthritis 20–30 years after meniscal resection. Resection relieves symptoms but does not protect the joint.
If the tear is repaired
pooled failure at five years and beyond. The inner zone has no blood supply, so a sutured tear heals with almost no biological support. Suturing closes the gap; it does not supply healing.
Redrawn from Schweizer C et al., KSSTA 2022. Two thirds of all failures occur within two years of surgery.
16-year-old man, bucket-handle tear of the right medial meniscus. Reinjury and locking followed an inside-out repair, ending in resection — the sequence that leads to the figure above.
Sources: Paradowski PT et al., Osteoarthritis Cartilage 2016 · Nepple JJ et al., J Bone Joint Surg Am 2012 — pooled repair failure 23.1% at ≥5 years · Schweizer C et al., KSSTA 2022.
From Impossible to Solved
Category A
Fibrin sealant reaches only 2–5 kPa in a wet field and degrades rapidly. It cannot hold tear-edge contact under load in a joint. Being blood-derived, it also carries consent requirements and supply limits.
Category B
Cyanoacrylate bonds strongly, but its degradation products raise cytotoxicity concerns and it is stiff and brittle once cured. It does not become a scaffold for healing.
Category C
Catechol adhesives depend on DOPA oxidation and chemical crosslinking inside the joint — chemistry left in the joint by design — and joint-level data remain at research stage.
The meniscus needs three conditions at once — wet adhesion, cell friendliness and biological activity. No existing material satisfied all three.
Molecular Design · FP-121
Inspired by the mussel foot protein fp-1: adhesive domains at both termini and one functional domain in the middle. Approximately 27 kDa, expressed in E. coli — animal-free and scalable.
N-term
FP1
Adhesive domain
binds wet surfaces
Centre
FP2
Functional domain
cell adhesion & growth
C-term
FP1
Adhesive domain
binds wet surfaces
FP-121 = FP1 – FP2 – FP1 · approx. 27 kDa · recombinant, E. coli
Interacts with –OH, –NH₂, –COOH and –SO₃H groups on tissue, so the bond holds in saline and under load.
63 kPa
Tensile, in saline (Category A: 2–5 kPa)
The central domain interacts with cell adhesion factors, so cells attach, spread and divide on the glue layer itself.
4.7×
HeLa proliferation vs negative control
No cytotoxic monomer, no crosslinker left in the joint. Optional Tyr→DOPA modification adds metal-ion coordination when more grip is needed.
No in-joint chemistry
Approx. 27 kDa · E. coli · animal-free
Mechanism of Action · Hypothesis
01 · Mechanical effect
Applied locally at the tear, FP-121 keeps the two surfaces in contact and stabilises the repaired site, so the knee provides a mechanically favourable environment for healing instead of shearing it apart.
Suturing alone cannot hold that contact.
02 · Biological effect
Synovial-derived cells are thought to drive meniscal repair. FP-121 promotes cell adhesion and migration in vitro, so the adhesive layer acts as a scaffold that cells can colonise and remodel.
The adhesive layer becomes the scaffold.
Stabilisation and biological acceleration are not alternatives here. Novelglue delivers both.
Kim W, Onodera T, Kondo E et al., Am J Sports Med 2020;48:1406–1415 (synovial-derived cells in meniscal repair) · Kawakami Y et al., Materials & Design 2025;255:114153 (FP-121 cell adhesion and migration).
Preclinical Study · Design
Treatment group
Local application of 20 mg FP-121, followed by two vertical mattress sutures.
Control group
The current standard of care for a longitudinal tear, with no augmentation.
Kagawa University, Department of Orthopaedic Surgery × Novelgen Co., Ltd. Presented at the Japanese Orthopaedic Society for Sports Medicine (JSOA) 2026.
Results · 12 Weeks
Suture only
Tear line remains open
FP-121 + suture
Tear surface continuous
Modified Miguel score: p = 0.03 (Wilcoxon signed-rank test, n = 6 per group). FP-121 augmentation produced a significant macroscopic improvement over suturing alone.
Modified Ishida score (0–6): median 3.5 versus 0 (p = 0.062). Bridging of the tear by repair tissue decides whether a meniscus survives.
Safranin O staining showed fibrocartilage-like tissue with cellular components and matrix formation — not simple scar.
Bridging was seen in 5 of 6 knees, against 1 of 6 with suture alone. FP-121 changed it from the exception to the rule.
8.3 ± 20.4% with suture alone versus 50.1 ± 25.3% with FP-121 (paired t-test, p = 0.025).
Healing rate = healing length ÷ total tear length × 100. Histological healing was defined as bridging of the injured site by repair tissue.
Scoring: Nakagawa Y et al., Osteoarthritis and Cartilage 2015 (modified Miguel score) · Ishida K et al., Tissue Eng 2007 (modified Ishida score). Rabbit medial meniscus longitudinal tear model, 12 weeks postoperative. All results are from preclinical (animal) studies.
Competitive Analysis
Benchmarked on the four requirements for a meniscal repair augmentation. Competitor products are anonymised by category, based on published literature and product labelling.
| Requirement | FP-121Recombinant marine protein | Category AFibrin-based sealant | Category BCyanoacrylate-type | Category CCatechol · research stage |
|---|---|---|---|---|
| Wet adhesion | ◎ 63 kPa tensile, in saline | △ 2–5 kPa cannot hold under load | ○ Strong brittle once cured | ○ Strong depends on crosslinking |
| Cell compatibility | ◎ Adhesion, growth, migration no chemical modification | ○ Good biocompatible | × Toxic products cytotoxicity concern | △ Concerns oxidation, crosslinking |
| Demonstrated healing | ◎ 50.1% healing · 5/6 bridged rabbit meniscus, 12 weeks | △ Limited durability insufficient | × Not applicable no healing activity | × No joint data research stage |
| Supply & logistics | ◎ E. coli · animal-free ambient 12 mo · no consent | △ Blood-derived consent, supply limits | ○ Synthetic stable supply | △ Mostly extracted scale-up unsolved |
Characteristics from published literature (Bochynska 2016; Kawakami 2025) and product labelling. FP-121 values from Novelgen internal data and the Kagawa University rabbit study.
Business Model
Unit
One vial per meniscal repair, sold alongside the suture system the surgeon already buys. No capital equipment, no new technique to learn.
Cost base
E. coli expression, animal-free inputs, ambient logistics. No donor plasma, no cold chain, no cell handling. Ambient, light-protected shelf life of 12 months.
Route
Direct in Japan; licence or co-development with orthopaedic and pharma partners in the US and Europe.
Two numbers, read together
$697M
What we sell into
The device market a vial is priced within (2030)
$5.7–15B
What we remove
Annual US cost of treating knee OA downstream
A consumable priced in the hundreds of millions can defer a burden measured in the billions. That gap is the case for reimbursement.
465k
partial meniscectomies a year in the US — tissue removed, not repaired
3 in 4
develop radiographic knee OA within 20–30 years
1M
hip and knee replacements a year in the US, the end of that chain
Sources: Katz JN et al., N Engl J Med 2013 · Paradowski PT et al., Osteoarthritis Cartilage 2016 · Osteoarthritis Action Alliance · ClinicoEconomics and Outcomes Research 2021.
Market Opportunity
A single E. coli expression platform supplies all three product classes. Meniscal repair is the entry point; cartilage and bone repair follow.
01 · Entry
2030 forecast / CAGR 5.5%
We enter as an augmentation to suturing — no change of technique, just a higher healing rate on top of what surgeons already do.
Source: Grand View Research (2023–2030)
02 · Expansion
2030 forecast / CAGR 13.7%
Scaffold and fixation for articular cartilage defects. Fibrocartilage is the fastest-growing segment at over 14% a year.
Source: Mordor Intelligence (2025–2030)
03 · Core
2030 forecast / CAGR 6.0%
Fixing sub-5 mm fragments in comminuted fractures, and β-TCP bone putty. Joint research with Kyoto University (AMED seed H).
Source: Bone graft substitute market survey (2024)
Global Expansion · Sequence
2026–2028
Value anchor
Partner access
Ambient logistics, animal-free supply, one manufacturing platform.
Clinical sites abroad, regulatory counsel per region, distribution reach.
Composition-of-matter patents in national phase in Japan, the US and Europe; a use patent for meniscal adhesion is filed.
Path to Market
Specification fixed · PMDA position
Filing-ready safety package
FIH started → market approval
Biological Safety
Results above are research grade. Regulatory filing requires repetition under GLP, planned for Phase 2.
1.41 g/kg
Estimated LD50, acute toxicity
2,100×
Margin over intended dose
Produced recombinantly in E. coli, so viral and prion transmission risk does not exist in principle. The patient consent form required for fibrin glue is unnecessary.
In a BALB 3T3 scratch assay, cell migration is promoted from 11.2 µg/mL upward — the material supports wound healing rather than impeding it.
Team & Collaborations
Lead clinical site · Principal investigator
Professor, Orthopaedic Surgery · Kagawa University
Grantee, AMED translational research seed A (2025–26, Hokkaido University hub)
Directs the meniscal programme: study design, surgery and evaluation in the rabbit model, and the clinical route to First-in-Human. Senior author of the JSOA 2026 study, with Ryuichi Isozaki and Masaki Mori performing surgery, histology and scoring in-house.
One protein, four clinical programmes: evidence from each site compounds across the platform.
Recombinant protein with adhesive and functional properties, and compositions containing it
Composition
FP-121 sequence and architecture
Method of use
meniscus, cartilage, bone repair
Manufacturing
DOPA conversion, purification
Formulation
excipients and stabilisation
Differentiated from prior art fp-151 (2007) and fp-131 (2011) by domain architecture and EGF activity. A use patent covering meniscal adhesion is filed.
Our Commitment
Surgery can cut, remove and stitch. It cannot make tissue hold. Novelglue does.
One vial, added to a suture procedure surgeons already know. No donor blood, no cold chain, no cell handling — so it reaches the hospitals that need it, not only the ones that can afford it.
4×
OA risk after a meniscal tear
Physical health — keeping the joint people walk on
20–29
Peak age of incidence
Mental health — young patients get their life back
11.5M
Annual DALYs from knee OA
Social health — mobility is participation
12 mo
Ambient, light-protected shelf life
Economic health — reachable where surgery is scarce
We are seeking capital and partners to reach First-in-Human: clinical sites in the US and Europe, regional regulatory counsel, and an orthopaedic or pharma partner for distribution.
Isozaki, R., Shishio, N., Kudo, K., Mori, M., Ogura, A., Ishikawa, M. (2026) Investigation of the therapeutic effects of marine adhesive protein in a rabbit medial meniscus longitudinal tear model , Japanese Orthopaedic Society for Sports Medicine (JSOA) .
香川大学医学部 整形外科 × 株式会社ノベルジェン。ウサギ内側半月板縦断裂モデルにおける FP-121 の非臨床試験。
Kawakami, Y. et al. (2025) Development of the FP121 series: Hybrid proteins mimicking marine adhesive proteins with cell adhesion and proliferation activity , Materials & Design , 255 , pp. 114153 .
View on ScienceDirect →Novelglue (FP121 シリーズ) の基盤論文。細胞接着・増殖活性・スクラッチアッセイ等の一次データを含む。
Kim, W., Onodera, T., Kondo, E. et al. (2020) Role of synovial-derived cells in meniscal repair , The American Journal of Sports Medicine , 48 , pp. 1406–1415 .
半月板修復において滑膜由来細胞が果たす役割。FP-121 の生物学的作用仮説の裏付け。
Paradowski, P. T. et al. (2016) Osteoarthritis of the knee after meniscal resection: long-term radiographic outcome , Osteoarthritis and Cartilage .
半月板切除から 20–30 年後、約 4 人に 3 人が X 線上の大腿脛骨関節 OA を発症。
Nepple, J. J. et al. (2012) Meniscal repair outcomes at greater than five years , The Journal of Bone and Joint Surgery (American) .
5 年以上の追跡における半月板縫合の統合失敗率 23.1%。
Schweizer, C. et al. (2022) Meniscal repair failure: timing and risk factors , Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA) .
半月板縫合後の再断裂の時期分布 (0–2 年 64% / 2–5 年 23% / 5 年超 13%)。
Snoeker, B. A. M. et al. (2013) Risk factors for meniscal tears: a systematic review including meta-analysis , Journal of Orthopaedic & Sports Physical Therapy .
半月板損傷後の長期的な変形性膝関節症リスクが約 4 倍に上昇することを示す。
Nakagawa, Y. et al. (2015) Macroscopic evaluation of meniscal healing (modified Miguel score) , Osteoarthritis and Cartilage .
本試験のマクロ評価スコアの出典。
Ishida, K. et al. (2007) Histological evaluation of meniscal repair tissue , Tissue Engineering .
本試験の組織学的評価スコア (modified Ishida score) の原典。
Katz, J. N. et al. (2013) Surgery versus physical therapy for a meniscal tear and osteoarthritis , The New England Journal of Medicine .
米国における半月板部分切除の実施規模および治療選択の議論。
