KGF (Keratinocyte Growth Factor)
KGF (FGF-7) is a 163-amino acid growth factor that specifically targets keratinocytes via the FGFR2-IIIb receptor, with clinical applications in mucositis treatment, wound healing, and hair follicle biology.
Overview
KGF was first identified in 1989 from conditioned media of human embryonic lung fibroblasts. It is a natural paracrine mediator of epithelial growth and differentiation, with expression dramatically upregulated (up to 160-fold) during wound healing. The recombinant form, palifermin (Kepivance), is FDA-approved for the prevention of severe oral mucositis in hematologic malignancy patients undergoing myeloablative therapy and stem cell transplantation. Beyond oncology, KGF is studied for its protective effects on epithelial tissues of the skin, lungs, gastrointestinal tract, and bladder. In cosmetics, biosynthetic KGF is used in formulations targeting skin barrier repair and hair growth.
Mechanism of Action
KGF binds with high affinity to FGFR2-IIIb (also called KGFR), a splice variant of the FGF receptor 2 expressed almost exclusively on epithelial cells. Receptor binding triggers dimerization and activation of intracellular tyrosine kinase domains, initiating the RAS-MAPK and PI3K-AKT signaling cascades. These pathways drive keratinocyte proliferation, migration, and differentiation while simultaneously upregulating anti-apoptotic factors (Bcl-2, Bcl-xL) and cytoprotective enzymes (Nrf2 pathway). KGF also stimulates production of detoxifying enzymes in epithelial cells, providing protection against reactive oxygen species and cytotoxic agents. The strict epithelial specificity of FGFR2-IIIb ensures that KGF does not stimulate fibroblast or endothelial cell proliferation, reducing concerns about fibrosis or aberrant angiogenesis Finch & Rubin (2004).
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Research
Mucositis Prevention (FDA-Approved)
Palifermin is FDA-approved for prevention of severe oral mucositis in patients with hematologic malignancies receiving myeloablative conditioning regimens followed by autologous stem cell transplantation. In pivotal clinical trials, palifermin reduced the incidence of WHO grade 3-4 oral mucositis from 98% to 63% and shortened the duration of severe mucositis by 3 days compared to placebo. Patients reported significantly less oral pain, reduced need for opioid analgesics, and improved ability to eat and drink Spielberger et al. (2004).
Wound Healing
KGF expression increases up to 160-fold at wound sites within 24 hours of injury, making it one of the most dramatically upregulated factors in the wound healing response. Exogenous KGF accelerates re-epithelialization by stimulating keratinocyte proliferation at wound margins and promoting migration across the wound bed. In animal models, topical KGF application has demonstrated accelerated closure of full-thickness wounds, improved epithelial barrier function, and enhanced tensile strength of healed tissue. KGF is particularly effective in impaired healing models, including diabetic wounds and radiation-damaged skin Werner (1998).
Hair Follicle Biology
FGFR2-IIIb is expressed in the outer root sheath and matrix cells of hair follicles, and KGF signaling plays a critical role in hair follicle morphogenesis and cycling. KGF promotes proliferation of follicular keratinocytes during the anagen (growth) phase and protects the follicular epithelium from apoptosis during catagen. Topical and injectable KGF formulations have shown promise in stimulating hair growth in androgenetic alopecia research models. KGF also protects hair follicles from chemotherapy-induced damage, with preclinical studies demonstrating preservation of hair follicle structure when KGF is administered prior to cytotoxic agents Danilenko et al. (1995)80002-6).
Radiation Protection
KGF protects epithelial tissues from radiation injury by stimulating proliferation of progenitor cells and upregulating DNA repair and antioxidant enzymes. In radiation therapy patients, palifermin has reduced the severity of radiation-induced oral mucositis. Preclinical studies have demonstrated protective effects on skin, intestinal mucosa, and lung epithelium when KGF is administered before irradiation Farrell et al. (1999)1097-0215(19990924)83:1%3C105::aid-ijc19%3E3.0.co;2-y).
Mucosal and epithelial cytoprotection
Palifermin (KGF-1), a member of the fibroblast growth factor family, binds the KGF receptor on epithelial cells to stimulate proliferation, differentiation, and thickening of the oral and gastrointestinal mucosa. This provides a thicker, more resistant barrier against chemoradiotherapy-induced injury.
- Induces epithelial thickening of non-keratinized oral mucosa and GI tract in preclinical models
- Reduces incidence and duration of severe oral mucositis in TBI-based autologous transplant regimens
Graft-versus-host disease and allogeneic transplant
Palifermin has been studied for modulating acute GVHD and mucositis in allogeneic HSCT, but results have been less favorable than in the autologous TBI setting.
- Randomized data in matched-donor allogeneic HSCT did not show reduced acute GVHD or grade 3-4 oral mucositis
- Meta-analysis found mixed efficacy across non-TBI and allogeneic conditioning regimens
Safety Profile
Palifermin has been extensively evaluated in clinical trials with a well-characterized safety profile. The most common adverse effects include dysgeusia (taste alteration), tongue thickening, tongue discoloration, oral/perioral dysesthesia, skin rash, pruritus, erythema, and edema. These effects are generally mild to moderate, transient, and resolve within days of discontinuation. Because KGF acts exclusively on FGFR2-IIIb-expressing epithelial cells, it does not stimulate fibroblast or endothelial proliferation, reducing fibrotic and angiogenic risks. However, theoretical concerns exist regarding stimulation of FGFR2-IIIb-expressing tumors; palifermin is contraindicated in patients with known FGFR2-IIIb-expressing malignancies. Long-term safety surveillance has not identified increased cancer incidence in treated patients. Topical cosmetic formulations use KGF at concentrations far below therapeutic doses and have not been associated with significant adverse effects.
Gastrointestinal Protection
KGF exerts protective effects on gastrointestinal epithelium, which also expresses FGFR2-IIIb. Preclinical studies have demonstrated that KGF pretreatment reduces chemotherapy-induced intestinal mucositis, radiation enteritis, and inflammatory bowel disease severity. KGF promotes proliferation of intestinal crypt stem cells, thickens the mucosal barrier, and increases mucus production. These findings suggest potential applications beyond oral mucositis, though clinical development has focused on the FDA-approved indication Houchen et al. (1999).
Lung Epithelial Protection
FGFR2-IIIb is expressed on alveolar type II pneumocytes, and KGF stimulates surfactant production, alveolar epithelial repair, and edema clearance. Preclinical research has explored KGF for acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and ventilator-induced lung injury. Intravenous palifermin increased alveolar epithelial fluid clearance in human ex vivo lung perfusion models, suggesting potential for treating pulmonary edema and improving lung transplant outcomes McAuley et al. (2004).
Pharmacokinetic Profile
KGF (Keratinocyte Growth Factor) — Pharmacokinetic Curve
Intravenous (Palifermin), Topical (cosmetic)Quick Start
- Route
- Intravenous (Palifermin), Topical (cosmetic)
Molecular Structure
- Formula
- Protein (~19 kDa)
- CAS
- 162394-19-6 (Palifermin)
Research Indications
Approved Indications
FDA-approved (2004) to decrease the incidence and duration of severe oral mucositis in patients with hematologic malignancies receiving myelotoxic therapy requiring hematopoietic stem cell support. Recombinant human keratinocyte growth factor (KGF-1) stimulates epithelial proliferation to protect the mucosal lining.
Investigational Uses
Randomized trial evidence supports reduced severe oral mucositis during multicycle chemotherapy, though it is not FDA-approved outside the transplant setting.
Research Protocols
oral
The recombinant form, palifermin (Kepivance), is FDA-approved for the prevention of severe oral mucositis in hematologic malignancy patients undergoing myeloablative therapy and stem cell transplantation. Research Mucositis Prevention (FDA-Approved) Palifermin is FDA-approved for prevention of seve
topical
In animal models, topical KGF application has demonstrated accelerated closure of full-thickness wounds, improved epithelial barrier function, and enhanced tensile strength of healed tissue. Topical and injectable KGF formulations have shown promise in stimulating hair growth in androgenetic alopeci
intravenous Injection
Intravenous palifermin increased alveolar epithelial fluid clearance in human ex vivo lung perfusion models, suggesting potential for treating pulmonary edema and improving lung transplant outcomes [McAuley et al. Clinical (palifermin) formulations are administered intravenously as a lyophilized pow
| Goal | Dose | Frequency | Duration |
|---|---|---|---|
| General Research Protocol | 60 mcg | Per protocol | 3 days |
What to Expect
What to Expect
Effects begin within hours of administration based on half-life of ~4.5 hours (Palifermin IV)
In pivotal clinical trials, palifermin reduced the incidence of WHO grade 3-4 oral mucositis from 98% to 63% and shortened the duration of severe...
Due to short half-life (~4.5 hours (Palifermin IV)), effects are expected per-dose; consistent daily administration maintains therapeutic levels
In pivotal clinical trials, palifermin reduced the incidence of WHO grade 3-4 oral mucositis from 98% to 63% and shortened the duration of severe...
Regular administration schedule required; effects are dose-dependent and do not persist between doses
Quality Indicators
What to look for
- Human clinical trials conducted
- Well-established safety profile
- Multiple peer-reviewed studies available
Frequently Asked Questions
References (15)
- [17]Liu et al — KGF-mimetic peptides for hair follicle regeneration: preclinical efficacy J. Invest. Dermatol. (2024)
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- [15]Chen et al — KGF-loaded electrospun nanofibers for accelerated wound re-epithelialization Acta Biomater. (2023)
- [16]Zhu et al — Palifermin for prevention of chemoradiation-induced mucositis: updated meta-analysis Support. Care Cancer (2022)
- [18]Santos et al — Recombinant KGF in biomaterial scaffolds for skin tissue engineering Biomaterials (2023)
- [12]Spielberger R, Stiff P, Bensinger W, et al. Palifermin for oral mucositis after intensive therapy for hematologic cancers New England Journal of Medicine (2004)
→ Pivotal double-blind, placebo-controlled phase III trial in 212 patients with hematologic malignancies undergoing autologous HSCT with TBI-based conditioning; palifermin 60 mcg/kg/day significantly reduced the incidence and duration of severe (WHO grade 3-4) oral mucositis. This trial supported FDA approval in 2004.
- [13]Le QT, Kim HE, Schneider CJ, et al. Single-dose palifermin prevents severe oral mucositis during multicycle chemotherapy in patients with cancer: a randomized trial Annals of Internal Medicine (2010)
→ Randomized, placebo-controlled trial showing that a single dose of palifermin per cycle reduced the incidence of severe oral mucositis during multicycle chemotherapy, extending evidence beyond the transplant setting.
- [14]Vadhan-Raj S, Goldberg JD, Perales MA, et al. Long-term safety outcomes in patients with hematological malignancies undergoing autologous hematopoietic stem cell transplantation treated with palifermin to prevent oral mucositis Biology of Blood and Marrow Transplantation (2016)
→ Pooled long-term safety analysis of 672 patients (428 palifermin, 244 placebo) across 4 phase I-III studies found no adverse effect on overall survival, disease progression, or incidence of secondary malignancies compared with placebo.
- [15]Vagliano L, et al. Efficacy of palifermin on oral mucositis and acute GVHD after hematopoietic stem cell transplantation (HSCT) in hematology malignancy patients: a meta-analysis of trials Contemporary Oncology (Poznan) (2017)
→ Meta-analysis of six randomized trials found benefit was strongest in TBI-based autologous transplant regimens; efficacy was less consistent in non-TBI and allogeneic settings, with more oral erythema reported in palifermin-treated patients.
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