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Introduction: Osteoarthritis (OA) is a serious and incurable disease leading the disability. Surgical treatment is the last but not necessarily the best approach for patients with high risks and costs. However, there are no disease-modifying OA drugs (DMOADs) developed for the disease so far, leaving a huge unmet need for drug treatments. Sprifermin is a recombinant human fibroblast growth factor 18 (rhFGF18) and has been confirmed to have anabolic effects on articular cartilage, which makes it a promising DMOAD., Areas Covered: The content of this review includes overview of the market, discovery and development, molecular mechanism, preclinical studies, clinical efficacy, safety, and tolerability of sprifermin. It examines the potential of sprifermin as a disease modifying drug for the treatment of knee OA., Expert Opinion: Sprifermin could be one of the most promising DMOADs, especially for cartilage phenotype. Current studies show good tolerability and no safety concerns. Well-designed phase 3 clinical trials are required to examine its effects on symptoms and cartilage loss in knee OA.

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent, dynamic disease that occurs across the age spectrum and can lead to cirrhosis and hepatocellular carcinoma. There are currently no US Food and Drug Administration (FDA) approved treatments for NAFLD; however, this is a field of active research. This review summarizes emerging pharmacotherapies for the treatment of adult and pediatric NAFLD. Investigated pharmacotherapies predominantly target bile acid signaling, insulin resistance, and lipid handling within the liver. Three drugs have gone on to phase III trials for which results are available. Of those, obeticholic acid is the single agent that demonstrates promise according to the interim analyses of the REGENERATE trial. Obeticholic acid showed reduction of fibrosis in adults with nonalcoholic steatohepatitis (NASH) taking 25 mg daily for 18 months (n = 931, reduction in fibrosis in 25% vs. 12% placebo, P < 0.01). Ongoing phase III trials include REGENERATE and MAESTRO-NASH, which investigates thyroid hormone receptor-β agonist MGL-3196. Outcomes of promising phase II trials in adults with NASH are also available and those have investigated agents, including the fibroblast growth factor (FGF)19 analogue NGM282, the GLP1 agonist liraglutide, the FGF21 analogue Pegbelfermin, the sodium glucose co-transporter 2 inhibitor Empagliflozin, the ketohexokinase inhibitor PF-06835919, the acetyl-coenzyme A carboxylase inhibitor GS-0976, and the chemokine receptor antagonist Cenicriviroc. Completed and ongoing clinical trials emphasize the need for a more nuanced understanding of the phenotypes of subgroups within NAFLD that may respond to an individualized approach to pharmacotherapy., (© 2020 The Authors. Clinical and Translational Science published by Wiley Periodicals LLC on behalf of the American Society for Clinical Pharmacology and Therapeutics.)

Introduction : Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and is strongly associated with obesity and insulin resistance. NAFLD refers to a spectrum of disorders ranging from asymptomatic hepatic steatosis (nonalcoholic fatty liver, NAFL) to nonalcoholic steatohepatitis (NASH), which increases the risk of developing more severe forms of liver disease such as progressive fibrosis, cirrhosis, and liver cancer. Currently, there are no food and drug administration (FDA) approved drugs to treat NASH. Pegbelfermin (BMS-986036) is a PEGylated fibroblast growth factor 21 (FGF21) analogue that is under investigation for the treatment of NASH. Areas covered : We reviewed the (pre)clinical pegbelfermin studies and compared these with other studies that assessed FGF21 and FGF21 analogues in the treatment of NASH. Expert opinion : With no FDA approved treatments available for NASH, there is an urgent need for novel therapies. Pegbelfermin is a systemic treatment with pleiotropic effects on various tissues. Short-term adverse effects are limited, but more research is required to study potential long-term safety issues. In a phase 2a trial, pegbelfermin has shown promising improvements in several NASH related outcomes. However, clinical trials demonstrating long-term benefits on hard outcomes such as liver histology, cirrhosis development, or survival are required for further validation.

Importance: Sprifermin is under investigation as a disease-modifying osteoarthritis drug., Objective: To evaluate the effects of sprifermin on changes in total femorotibial joint cartilage thickness in the more symptomatic knee of patients with osteoarthritis., Design, Setting, and Participants: FORWARD (FGF-18 Osteoarthritis Randomized Trial with Administration of Repeated Doses) was a 5-year, dose-finding, multicenter randomized clinical trial conducted at 10 sites. Eligible participants were aged 40 to 85 years with symptomatic, radiographic knee osteoarthritis and Kellgren-Lawrence grade 2 or 3. Enrollment began in July 2013 and ended in May 2014; the last participant visit occurred on May 8, 2017. The primary outcome at 2 years and a follow-up analysis at 3 years are reported., Interventions: Participants were randomized to 1 of 5 groups: intra-articular injections of 100 μg of sprifermin administered every 6 months (n = 110) or every 12 months (n = 110), 30 μg of sprifermin every 6 months (n = 111) or every 12 months (n = 110), or placebo every 6 months (n = 108). Each treatment consisted of weekly injections over 3 weeks., Main Outcomes and Measures: The primary end point was change in total femorotibial joint cartilage thickness measured by quantitative magnetic resonance imaging at 2 years. The secondary end points (of 15 total) included 2-year change from baseline in total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. The minimal clinically important difference (MCID) is unknown for the primary outcome; for total WOMAC score in patients with hip and knee osteoarthritis, the absolute MCID is 7 U (95% CI, 4 to 10 U) and the percentage MCID is 14% (95% CI, 9% to 18%)., Results: Among 549 participants (median age, 65.0 years; 379 female [69.0%]), 474 (86.3%) completed 2-year follow-up. Compared with placebo, the changes from baseline to 2 years in total femorotibial joint cartilage thickness were 0.05 mm (95% CI, 0.03 to 0.07 mm) for 100 μg of sprifermin administered every 6 months; 0.04 mm (95% CI, 0.02 to 0.06 mm) for 100 μg of sprifermin every 12 months; 0.02 mm (95% CI, -0.01 to 0.04 mm) for 30 μg of sprifermin every 6 months; and 0.01 mm (95% CI, -0.01 to 0.03 mm) for 30 μg of sprifermin every 12 months. Compared with placebo, there were no statistically significant differences in mean absolute change from baseline in total WOMAC scores for 100 μg of sprifermin administered every 6 months or every 12 months, or for 30 μg of sprifermin every 6 months or every 12 months. The most frequently reported treatment-emergent adverse event was arthralgia (placebo: n = 46 [43.0%]; 100 μg of sprifermin administered every 6 months: n = 45 [41.3%]; 100 μg of sprifermin every 12 months: n = 50 [45.0%]; 30 μg of sprifermin every 6 months: n = 40 [36.0%]; and 30 μg of sprifermin every 12 months: n = 48 [44.0%])., Conclusions and Relevance: Among participants with symptomatic radiographic knee osteoarthritis, the intra-articular administration of 100 μg of sprifermin every 6 or 12 months vs placebo resulted in an improvement in total femorotibial joint cartilage thickness after 2 years that was statistically significant, but of uncertain clinical importance; there was no significant difference for 30 μg of sprifermin every 6 or 12 months vs placebo. Durability of response also was uncertain., Trial Registration: ClinicalTrials.gov Identifier: NCT01919164.

Objective: NGM282 is an analog of fibroblast growth factor 19 (FGF19), a potent inhibitor of bile acid (BA) synthesis in animals and humans. In phase 2 trials in type 2 diabetes and primary biliary cholangitis, NGM282 was associated with dose-related abdominal cramping and diarrhea. We aimed to examine effects of NGM282 on colonic transit, stool frequency and consistency, hepatic BA synthesis (fasting serum C4), fecal fat, and BA in functional constipation (FC)., Methods: Two-dose NGM282 (1 and 6 mg, subcutaneously daily), parallel-group, randomized, placebo-controlled, 14-day study in patients with FC (Rome III criteria) and baseline colonic transit 24 h geometric center (GC) <3.0. We explored treatment interaction with SNPs in genes KLB, FGFR4, and TGR5 (GPBAR1)., Statistical Analysis: overall ANCOVA at α = 0.025 (baseline as covariate where available), with three pairwise comparisons among the three groups (α = 0.008)., Results: Overall, NGM282 altered bowel function (number of bowel movements, looser stool form, and increased ease of passage) and significantly accelerated gastric and colonic transit. Dose-related effects were seen with GC 24 h, but not with gastric emptying (GE) and GC 48 h. There were no differences in fecal fat or weight, but there was reduced fecal total BA excretion with NGM282. The most common adverse events were increased appetite (n = 0 with placebo, 2 with 1 mg, 9 with 6 mg), injection site reaction (n = 2 placebo, 4 with 1 mg, 8 with 6 mg), and diarrhea (n = 1 with 1 mg and 4 with 6 mg NGM282). There was treatment interaction with KLB SNP, with greater increase in colonic transit in participants with the minor A allele (p = 0.056)., Conclusion: NGM282 significantly impacts GE and colonic transit, consistent with the observed clinical symptoms. The specific mechanism of prokinetic activity requires further research.

Aims: To assess the safety, tolerability, pharmacokinetics and pharmacodynamics of PF-05231023, a long-acting fibroblast growth factor 21 (FGF21) analogue, in obese people with hypertriglyceridaemia on atorvastatin, with or without type 2 diabetes., Methods: Participants received PF-05231023 or placebo intravenously once weekly for 4 weeks. Safety (12-lead ECGs, vital signs, adverse events [AEs], laboratory tests) and longitudinal weight assessments were performed. Blood samples were collected for pharmacokinetic and pharmacodynamic analyses. Cardiovascular safety studies were also conducted in telemetered rats and monkeys. Blood pressure (BP; mean, systolic and diastolic) and ECGs were monitored., Results: A total of 107 people were randomized. PF-05231023 significantly decreased mean placebo-adjusted fasting triglycerides (day 25, 33%-43%) and increased HDL cholesterol (day 25, 15.7%-28.6%) and adiponectin (day 25, 1574 to 3272 ng/mL) across all doses, without significant changes in body weight (day 25, -0.45% to -1.21%). Modest decreases from baseline were observed for N-terminal propeptides of type 1 collagen (P1NP) on day 25, although C-telopeptide cross-linking of type 1 collagen (CTX-1) increased minimally. Systolic, diastolic BP, and pulse rate increased in a dose- and time-related manner. There were 5 serious AEs (one treatment-related) and no deaths. Three participants discontinued because of AEs. The majority of AEs were gastrointestinal. PF-05231023 increased BP and heart rate in rats, but not in monkeys., Conclusions: Once-weekly PF-05231023 lowered triglycerides markedly in the absence of weight loss, with modest changes in markers of bone homeostasis. This is the first report showing increases in BP and pulse rate in humans and rats after pharmacological administration of a long-acting FGF21 molecule., (© 2017 John Wiley & Sons Ltd.)

Background: Peripheral artery disease (PAD) is associated with a high clinical and socioeconomic burden. Treatments to alleviate the symptoms of PAD and decrease the risks of amputation and death are a high societal priority. A number of growth factors have shown a potential to stimulate angiogenesis. Growth factors delivered directly (as recombinant proteins), or indirectly (e.g. by viral vectors or DNA plasmids encoding these factors), have emerged as a promising strategy to treat patients with PAD., Objectives: To assess the effects of growth factors that promote angiogenesis for treating people with PAD of the lower extremities., Search Methods: The Cochrane Vascular Information Specialist searched the Specialised Register (June 2016) and CENTRAL (2016, Issue 5). We searched trial registries for details of ongoing or unpublished studies. We also checked the reference lists of relevant publications and, if necessary, tried to contact the trialists for details of the studies., Selection Criteria: We included randomised controlled trials comparing growth factors (delivered directly or indirectly) with no intervention, placebo or any other intervention not based on the growth factor's action in patients with PAD of the lower extremities. The primary outcomes were limb amputation, death and adverse events. The secondary outcomes comprised walking ability, haemodynamic measures, ulceration and rest pain., Data Collection and Analysis: Two review authors independently selected trials and assessed the risk of bias. We used outcomes of the studies at low risk of bias for the main analysis and of all studies in the sensitivity analyses. We calculated odds ratios (OR) for dichotomous outcomes and mean differences for continuous outcomes with 95% confidence intervals (CI). We evaluated statistical heterogeneity using the I 2 statistic and Cochrane's Q test. We conducted meta-analysis for the overall effect and for each growth factor as a subgroup analysis using OR in a fixed-effect model. We evaluated the robustness of the results in a sensitivity analysis using risk ratio (RR) and/or a random-effects model. We also assessed the quality of the evidence for each outcome., Main Results: We included 20 trials in the review and used 14 studies (on approximately 1400 participants) with published results in the analyses. Six published studies compared fibroblast growth factors (FGF), four studies hepatocyte growth factors (HGF) and another four studies vascular endothelial growth factors (VEGF), versus placebo or no therapy. Six of these studies exclusively or mainly investigated participants with intermittent claudication and eight studies exclusively participants with critical limb ischaemia. Follow-up generally ranged from three months to one year. Two small studies provided some data at 2 years and one of them also at 10 years.The direction and size of effects for growth factors on major limb amputations (OR 0.99, 95% CI 0.71 to 1.38; 10 studies, N = 1075) and death (OR 0.99, 95% CI 0.69 to 1.41; 12 studies, N = 1371) at up to two years are uncertain. The quality of the evidence is low due to risk of bias and imprecision (at one year, moderate-quality evidence due to imprecision). However, growth factors may decrease the rate of any limb amputations (OR 0.56, 95% CI 0.31 to 0.99; 6 studies, N = 415). The quality of the evidence is low due to risk of bias and selective reporting.The direction and size of effects for growth factors on serious adverse events (OR 1.09, 95% CI 0.79 to 1.50; 13 studies, N = 1411) and on any adverse events (OR 1.10, 95% CI 0.73 to 1.64; 4 studies, N = 709) at up to two years are also uncertain. The quality of the evidence is low due to risk of bias and imprecision (for serious adverse events at one year, moderate-quality evidence due to imprecision).Growth factors may improve haemodynamic measures (low-quality evidence), ulceration (very low-quality evidence) and rest pain (very low-quality evidence) up to one year, but they have little or no effect on walking ability (low-quality evidence). We did not identify any relevant differences in effects between growth factors (FGF, HGF and VEGF)., Authors' Conclusions: The results of this review do not support the use of therapy with the growth factors FGF, HGF or VEGF in people with PAD of the lower extremities to prevent death or major limb amputation or to improve walking ability. However, the use of these growth factors may improve haemodynamic measures and decrease the rate of any limb amputations (probably due to preventing minor amputations) with an uncertain effect on adverse events; an improvement of ulceration and rest pain is very uncertain. New trials at low risk of bias are needed to generate evidence with more certainty.

Fibroblast growth factor 21 (FGF21) is a promising regulator of glucose and lipid metabolism with multiple beneficial effects including hypoglycemic and lipid-lowering. Previous studies have reported that FGF21 is expected to become a new drug for treatment of diabetes. Liraglutide and insulin glargine are the two representative anti-diabetic biological drugs. In the current study, we aim to compare the long-term pharmacological efficacy of mFGF21 (an FGF21 analogue), liraglutide and insulin glargine in type 2 diabetic db/db mice. Db/db mice were initially treated with three kinds of proteins (25nmol/kg/day) by subcutaneous injection once a day for 4weeks, then subsequently be treated with once every two days for next 4weeks. After 8weeks of treatments, the blood glucose levels, body weights, glycosylated hemoglobin levels, fasting insulin levels, serum lipid profiles, hepatic biochemical parameters, oral glucose tolerance tests and hepatic mRNA expression levels of several proteins (GK, G6P, GLUT-1 and GLUT-4) associated with glucose metabolism of the experimental mice were detected. Results demonstrated that three proteins could significantly decrease the fed blood glucose levels of db/db mice. After treatment for 1week, the fed blood glucose levels of db/db mice in liraglutide group were significantly lower than those in mFGF21 and insulin glargine groups. However, after 2weeks of administration, the long-lasting hypoglycemic effect of mFGF21 was superior to liraglutide and insulin glargine up to the end of the experiments. Compared with liraglutide and insulin glargine, mFGF21 significantly reduced the glycosylated hemoglobin levels and improved the ability on glycemic control, insulin resistance, serum lipid and liver function states in db/db mice after 8weeks treatments. In addition, mFGF21 regulated glucose metabolism through increasing the mRNA expression levels of GK and GLUT-1, and decreasing the mRNA expression level of G6P. But liraglutide and insulin glargine could only up-regulate the mRNA expression of GLUT-4. In summary, as a hypoglycemic drug for long-term treatment, mFGF21 has the potential to be an ideal drug candidate for the therapy of type 2 diabetes., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Fibroblast growth factor (FGF) 21 belongs to a hormone-like subgroup within the FGF superfamily. The members of this subfamily, FGF19, FGF21 and FGF23, are characterized by their reduced binding affinity for heparin that enables them to be transported in the circulation and function in an endocrine manner. It is likely that FGF21 also acts in an autocrine and paracrine fashion, as multiple organs can produce this protein and its plasma concentration seems to be below the level necessary to induce a pharmacological effect. FGF21 signals via FGF receptors, but for efficient receptor engagement it requires a cofactor, membrane-spanning βKlotho (KLB). The regulation of glucose uptake in adipocytes was the initial biological activity ascribed to FGF21, but this hormone is now recognized to stimulate many other pathways in vitro and display multiple pharmacological effects in metabolically compromised animals and humans. Understanding of the precise physiology of FGF21 and its potential medicinal role has evolved exponentially over the last decade, yet numerous aspects remain to be defined and others are a source of debate. Here we provide a historical overview of the advances in FGF21 biology focusing on the uncertainties in the mechanism of action as well as the differing viewpoints relating to this intriguing protein., (© 2016 The Association for the Publication of the Journal of Internal Medicine.)

We evaluated the mitigating effects of fibroblast growth factor 4 and 7 (FGF4 and FGF7, respectively) in comparison with long acting protected graft copolymer (PGC)-formulated FGF4 and 7 (PF4 and PF7, respectively) administered to C57BL/6J mice a day after exposure to LD50/30 (15.7 Gy) partial body irradiation (PBI) which targeted the gastrointestinal (GI) system. The PGC that we developed increased the bioavailability of FGF4 and FGF7 by 5- and 250-fold compared to without PGC, respectively, and also sustained a 24 hr presence in the blood after a single subcutaneous administration. The dose levels tested for mitigating effects on radiation injury were 3 mg/kg for the PF4 and PF7 and 1.5 mg each for their combination (PF4/7). Amifostine administered prior to PBI was used as a positive control. The PF4, PF7, or PF4/7 mitigated the radiation lethality in mice. The mitigating effect of PF4 and PF7 was similar to the positive control and PF7 was better than other mitigators tested. The plasma citrulline levels and hematology parameters were early markers of recovery and survival. GI permeability function appeared to be a late or full recovery indicator. The villus length and crypt number correlated with plasma citrulline level, indicating that it can act as a surrogate marker for these histology evaluations. The IL-18 concentrations in jejunum as early as day 4 and TPO levels in colon on day 10 following PBI showed statistically significant changes in irradiated versus non-irradiated mice which makes them potential biomarkers of radiation exposure. Other colon and jejunum cytokine levels are potentially useful but require larger numbers of samples than in the present study before their full utility can be realized.

Objectives: To evaluate the safety of intra-articular sprifermin (primary), and to evaluate systemic exposure, biomarkers, histology, and other cartilage parameters in patients with advanced osteoarthritis (OA)., Methods: This was a first-in-human, double-blind, randomised, placebo-controlled trial of single and multiple ascending doses of sprifermin from 3-300 μg in knee OA patients scheduled for total knee replacement. Patients were randomised 3:1 to sprifermin or placebo, injected into the target knee once or once weekly for 3 weeks, and followed-up for 24 weeks., Results: Fifty-five patients were treated with sprifermin, 25 with single and 30 with multiple doses, 18 received placebo. There was no clear difference between the active and placebo groups in incidence, severity, and nature of reported treatment emergent adverse events. Acute inflammatory reactions were slightly more common with sprifermin 300 μg, but none led to discontinuation. No clear difference was seen between placebo and sprifermin in physician-assessed local tolerability, pain, or swelling in the knee. No meaningful changes over time, or differences between treatment groups, were observed for safety laboratory parameters or ECG. Although individual abnormalities were observed, no patterns were evident suggesting a relation to treatment or potential safety concern. No systemic sprifermin exposure, anti-FGF18 antibodies, or clear-cut effects on systemic biomarkers were detected., Conclusions: This first clinical trial of sprifermin revealed no serious safety concerns, although larger studies are needed. The possibility of positive effects of intra-articular sprifermin on histological and other cartilage parameters in knee OA also warrant further investigation.

Aims: The aim of the present study was to evaluate the pharmacokinetics/pharmacodynamics (PK/PD), safety and tolerability of single intravenous (IV) doses of PF-05231023, a long acting fibroblast growth factor 21 (FGF21) analogue being developed for the treatment of type 2 diabetes mellitus (T2DM)., Methods: T2DM subjects (glycosylated haemoglobin: 7.0-10.5%; on stable metformin therapy and/or diet and exercise) were randomized to receive a single dose of placebo or PF-05231023 (0.5-200 mg). Safety evaluations were performed up to 14 days after dosing. PK and PD endpoints were measured and a PK/PD model was developed for triglyceride - an early marker of drug activity., Results: No antidrug antibody or serious adverse events (AEs) were observed. The most frequent AEs were gastrointestinal but were generally mild. Plasma PF-05231023 levels peaked immediately post-IV dosing, with mean terminal half-lives of 6.5-7.7 h and 66.5- 96.6 h for intact C- and N-termini, respectively. Intact C-terminus exposures increased proportionally with increasing dose, whereas N-terminus exposures appeared to trend higher than dose-proportionally. Although no apparent effect on plasma glucose was seen, dose-dependent decreases in triglyceride were observed, with a maximum reduction of 48.5 ± 10.0% (mean ± standard deviation) for the 200 mg dose compared with a reduction of 19.1 ± 26.4% for placebo, demonstrating proof of pharmacology. Moreover, a reduction in total cholesterol and low-density lipoprotein cholesterol and an increase in high-density lipoprotein cholesterol were observed in the high-dose groups., Conclusions: Single IV doses of PF-05231023 up to 200 mg were generally safe and well tolerated by subjects with T2DM. The observed early sign of pharmacology supports further clinical testing of PF-05231023 upon repeated administration., (© 2015 The British Pharmacological Society.)

It has been demonstrated that circulating FGF21 levels are elevated in the serum and synovial fluid of patients with rheumatoid arthritis (RA). The aim of this study is to investigate efficacy of FGF21 for treatment of RA and the molecular mechanisms of the therapeutic effect on collagen-induced arthritis (CIA). Mice with CIA were subcutaneously administered with FGF21 (5, 2 or 1mg·kg(-1)·d(-1)), IL-1β antibody (5mg·kg(-1)·d(-1)), IL-17A antibody (5mg·kg(-1)·d(-1)) and dexamethasone (DEX) (1mg·kg(-1)·d(-1)), respectively. The effects of treatment were determined by arthritis severity score, histological damage and cytokine production. The activation of NF-κB was analyzed by Western blotting. We also detected the levels of oxidative stress parameters. Our results showed that FGF21 had beneficial effects on clinical symptom and histological lesion of CIA mice. Similar to antibody and DEX, FGF21 treatment alleviated the severity of arthritis by reducing humoral and cellular immune responses and down-regulating the expression of pro-inflammatory cytokines. FGF21 treatment also reduced the expression of TNF-α, IL-1β, IL-6, IFN-γ and MMP-3 and increased level of IL-10 in the spleen tissue or the plasma of CIA mice in a dose-dependent manner. Furthermore, FGF21 inhibited IκBα degradation and NF-κB p65 nuclear translocation and induced significant changes of oxidative stress parameters (MDA, SOD, CAT, GSH-PX and GSH) in the plasma. FGF21 exerts therapeutic efficacy for RA through antioxidant reaction and inhibiting NF-κB inflammatory pathway. This study provides evidence that FGF21 may be a promising therapeutic agent for RA patients., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Hepatic accumulation of bile acids is central to the pathogenesis of cholestatic liver diseases. Endocrine hormone fibroblast growth factor 19 (FGF19) may reduce hepatic bile acid levels through modulation of bile acid synthesis and prevent subsequent liver damage. However, FGF19 has also been implicated in hepatocellular carcinogenesis, and consequently, the potential risk from prolonged exposure to supraphysiological levels of the hormone represents a major hurdle for developing an FGF19-based therapy. We describe a nontumorigenic FGF19 variant, M70, which regulates bile acid metabolism and, through inhibition of bile acid synthesis and reduction of excess hepatic bile acid accumulation, protects mice from liver injury induced by either extrahepatic or intrahepatic cholestasis. Administration of M70 in healthy human volunteers potently reduces serum levels of 7α-hydroxy-4-cholesten-3-one, a surrogate marker for the hepatic activity of cholesterol 7α-hydroxylase (CYP7A1), the enzyme responsible for catalyzing the first and rate-limiting step in the classical bile acid synthetic pathway. This study provides direct evidence for the regulation of bile acid metabolism by FGF19 pathway in humans. On the basis of these results, the development of nontumorigenic FGF19 variants capable of modulating CYP7A1 expression represents an effective approach for the prevention and treatment of cholestatic liver diseases as well as potentially for other disorders associated with bile acid dysregulation., (Copyright © 2014, American Association for the Advancement of Science.)

Objective: To evaluate the efficacy and safety of intraarticular sprifermin (recombinant human fibroblast growth factor 18) in the treatment of symptomatic knee osteoarthritis (OA)., Methods: The study was a randomized, double-blind, placebo-controlled, proof-of-concept trial. Intraarticular sprifermin was evaluated at doses of 10 μg, 30 μg, and 100 μg. The primary efficacy end point was change in central medial femorotibial compartment cartilage thickness at 6 months and 12 months as determined using quantitative magnetic resonance imaging (qMRI). The primary safety end points were nature, incidence, and severity of local and systemic treatment-emergent adverse events (AEs) and acute inflammatory reactions, as well as results of laboratory assessments. Secondary end points included changes in total and compartment femorotibial cartilage thickness and volume as assessed by qMRI, changes in joint space width (JSW) seen on radiographs, and pain scores on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)., Results: One hundred ninety-two patients were randomized and evaluated for safety, 180 completed the trial, and 168 were evaluated for the primary efficacy end point. We found no statistically significant dose response in change in central medial femorotibial compartment cartilage thickness. Sprifermin was associated with statistically significant, dose-dependent reductions in loss of total and lateral femorotibial cartilage thickness and volume and in JSW narrowing in the lateral femorotibial compartment. All groups had improved WOMAC pain scores, with statistically significantly less improvement at 12 months in patients receiving the 100-μg dose of sprifermin as compared with those receiving placebo. There was no significant difference in serious AEs, treatment-emergent AEs, or acute inflammatory reactions between sprifermin and placebo groups., Conclusion: No statistically significant relationship between treatment group and reduction in central medial femorotibial compartment cartilage thickness was observed; however, prespecified structural secondary end points showed statistically significant dose-dependent reductions after sprifermin treatment. Sprifermin was not associated with any local or systemic safety concerns., (Copyright © 2014 by the American College of Rheumatology.)

Thyroid hormone (TH) regulates fibroblast growth factor 21 (FGF21) levels in the liver and in the adipose tissue. In contrast, peripheral FGF21 administration leads to decreased circulating levels of TH. These data suggest that FGF21 and TH could interact to regulate metabolism. In the present study, we confirmed that TH regulates adipose and hepatic FGF21 expression and serum levels in mice. We next investigated the influence of TH administration on key serum metabolites, gene expression in the liver and brown adipose tissue, and energy expenditure in FGF21 knockout mice. Surprisingly, we did not observe any significant differences in the effects of TH on FGF21 knockout mice compared with those in wild-type animals, indicating that TH acts independently of FGF21 for the specific outcomes studied. Furthermore, exogenous FGF21 administration to hypothyroid mice led to similar changes in serum and liver lipid metabolites and gene expression in both hypothyroid and euthyroid mice. Thus, it appears that FGF21 and TH have similar actions to decrease serum and liver lipids despite having some divergent regulatory effects. Whereas TH leads to up-regulation in the liver and down-regulation in brown adipose tissue of genes involved in the lipid synthesis pathway (eg, fatty acid synthase (FASN) and SPOT14), FGF21 leads to the opposite changes in expression of these genes. In conclusion, TH and FGF21 act independently on the outcomes studied, despite their ability to regulate each other's circulating levels. Thus, TH and FGF21 may modulate the availability of each other in critical metabolic states.

Disabilities triggered by neurodegeneration mainly result in mortality in the elderly, and patients with neurodegenerative disease also display deficits in olfactory function. Therefore drug distribution to the brain through intranasal administration has become one of the most difficult challenges in the treatment of central nervous system (CNS) diseases. TAT-human acidic fibroblast growth factor (HaFGF) is a new fused protein retaining the neuroprotective activities of HaFGF, and is a promising prospect in the treatment of neurodegenerative diseases. TAT (a cell-penetrating peptide) contains a high relative abundance of positively charged amino acids such as lysine and arginine, which have a powerful attraction to the negatively charge on the nasal epithelial membrane. The present study focused on the evaluation of the safety and absorption characteristics of TAT-HaFGF following intranasal administration. After TAT-HaFGF intranasal administration (100, 300, 600 µg/kg) for 5 weeks, hematoxylin-eosin (HE) staining showed no pathology in any of the investigated tissues and organs. The expression of olfactory marker protein (OMP) was observed with immunohistochemical staining, which showed no altered expression in the sensory neurons of the nasal epithelium. Nasal ciliotoxicity studies carried out using an in situ palate model and optical microscope showed that TAT-HaFGF had no nasal ciliotoxicity. The distribution of the TAT-HaFGF following intranasal administration was assessed using a radioisotopic tracing method. Radioactivity was observed in the brain after 15 min. This became stronger at 30 min and weaker at 1 h. All of the results confirmed the in vivo safety of TAT-HaFGF via intranasal administration.

Purpose: The aim of this project was to review the literature and define clinical practice guidelines for the use of cytokines and growth factor agents for the prevention or treatment of oral mucositis induced by cancer chemotherapy or radiotherapy., Methods: A systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society for Oral Oncology (MASCC/ISOO). The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: Recommendation, Suggestion, No guideline possible., Results: Sixty-four clinical studies across 11 interventions were evaluated. A recommendation was made for the use of recombinant human KGF-1 (palifermin) at a dose of 60 μg/kg per day for 3 days prior to conditioning treatment and for 3 days post-transplant for prevention of oral mucositis in patients receiving high-dose chemotherapy and total body irradiation followed by autologous stem cell transplantation for hematological malignancies. A suggestion was made against using granulocyte macrophage colony-stimulating factor mouthwash for the prevention of oral mucositis in the setting of high-dose chemotherapy followed by autologous or allogeneic stem cell transplantation. No guideline was possible for any other cytokine or growth factor agents due to inconclusive evidence., Conclusions: Of the cytokine and growth factor agents studied for oral mucositis, the evidence only supports use of palifermin in the specific population listed above. Additional well-designed research is needed on other cytokine and growth factor interventions and in other cancer treatment settings.

Introduction: Basic fibroblast growth factor (bFGF) has been shown to reduce volume in acute ischemic stroke models, and to promote functional recovery as well as new synapse formation when given to animals with completed cerebral infarction. A recombinant native form of human bFGF, trafermin, has been tested in Phase III clinical trials in patients with stroke., Areas Covered: The role of trafermin in stroke. Data were identified by searching PubMed for single or combined terms including: trafermin, basic fibroblast growth factors, neuroprotection, neuroprotective drugs, stroke therapy, stroke rehabilitation and acute stroke. Original research papers, clinical series and reviews are included. Our research covered all relevant data up until 1 April 2011., Expert Opinion: To date, all Phase III trials have failed to demonstrate the superiority of trafermin over placebo when given within 6 h from stroke onset because trafermin causes a dose-dependent hypotension and an increased mortality rate in treated patients. However, a 24-h intravenous infusion seems to be safe for stroke patients and may result in an improved outcome when given 5 - 6 h after infarct. This finding may open renewed interest in restorative treatment for stroke, which could enhance recovery mechanisms rather than immediate neuroprotection. Studies suggest that growth factors can produce improvement in animal models of stroke, even when administered at postischemic intervals from many hours to days, when conventional neuroprotective approaches are typically ineffective. Because of the number of side effects and increased mortality reported in the first clinical studies with high dose of FGF, further experimental studies are necessary to asses whether it is possible to achieve a pharmacologically significant therapeutic level in the brain, by minimizing peripheral side effects. Another randomized clinical trial is needed to test trafermin in stroke patients but to enhance functional recovery.

Aims: Assessment of the safety, efficacy and effectiveness of growth factors alone or in combination with other technologies in the treatment of DFU including medical, economical, social, ethical and juridical aspects., Methods: We systematically searched relevant data bases limited to English and German language and publications since 1990. Review and assessment of the quality of publications followed methods conforming to widely accepted standards for evidence-based medicine and health economics., Results: We identified 25 studies comparing becaplermin, rhEGF, bFGF and the metabolically active skin grafts Dermagraft and Apligraf with standard wound care (SWC) alone or extracellular wound matrix. Study duration ranged from 12 to 20 weeks and the study population comprised between 17 and 382 patients. Treatment with becaplermin, rhEGF, Dermagraft and Apligraf resulted in a higher incidence of complete wound closure and shorter time to complete wound healing with statistically significant differences. Regarding the proportion of adverse events there was no difference between treatment groups. The methodological quality of the studies was affected by significant deficiencies. Economic evaluations showed becaplermin being cost-effective., Conclusions: Add-on therapy with growth factors and active skin substitutes for treating uncomplicated DFU could be an alternative to SWC alone. For explicit recommendations further studies with stronger evidence are necessary., (© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.)

Tumor-induced osteomalacia (TIO) is a rare acquired paraneoplastic disease characterized by renal phosphate wasting and hypophosphatemia. Recently, it was reported that tumors associated with TIO produce fibroblast growth factor (FGF) 23, identified as the last member of the FGF family and of which excessive action causes several hypophosphatemic diseases whereas deficient FGF23 activity results in hyperphosphatemic tumoral calcinosis. In this case, although it was difficult to locate the associated tumor, an abnormal mass in the left maxilla was detected by imaging. The tumor was removed by partial resection of the left maxillary alveolar region. Thereafter, serum level of FGF23 rapidly decreased, hypophosphatemia improved, and the clinical symptoms greatly improved. Histopathologic diagnosis of the tumor was phosphaturic mesenchymal tumor, mixed connective tissue variant. Immunohistochemical findings confirmed that the removed tumor produced FGF23. These results indicate that development of osteomalacia in this patient was related to the maxillary tumor, which overexpressed FGF23., (Copyright 2010 Mosby, Inc. All rights reserved.)

Fibroblast growth factor 21 (FGF21) is a novel metabolic regulator produced primarily by the liver that exerts potent antidiabetic and lipid-lowering effects in animal models of obesity and type 2 diabetes mellitus. This hormone contributes to body weight regulation and is strongly involved in the response to nutritional deprivation and ketogenic state in mice. The principal sites of metabolic actions of FGF21 are adipose tissue, liver and pancreas. Experimental studies have shown marked improvements in diabetes compensation and dyslipidemia after FGF21 administration in diabetic mice and primates. Positive metabolic actions of FGF21 without the presence of apparent side effects make this factor a hot candidate to treat type 2 diabetes and accompanying metabolic diseases. The aim of this review is to summarize the current knowledge about the metabolic effects of FGF21 including some preliminary data on changes of its levels in humans with a special emphasis on its therapeutic potential in type 2 diabetes mellitus.

Goals of Work: The objective of this study was to evaluate the safety and tolerability of velafermin in patients at risk of developing severe oral mucositis (OM) from chemotherapy., Materials and Methods: This study was a single-center, open-label, single-dose escalation, phase I trial in patients undergoing high-dose chemotherapy (HDCT) and autologous peripheral blood stem cell transplant (PBSCT). Velafermin was administered 24 h after stem cell infusion as a single intravenous dose infused over 15 min. Clinical safety variables were assessed and OM status scored daily for 30 days using the World Health Organization (WHO) grading scale., Main Results: Thirty patients were treated with velafermin at doses of 0.03 (n = 10), 0.1 (n = 10), 0.2 (n = 8), or 0.33 mg/kg (n = 2). Patients were diagnosed with multiple myeloma (n = 16), non-Hodgkin's lymphoma (n = 12), acute myelogenous leukemia (n = 1), or desmoplasmic round cell tumor (n = 1). Velafermin was well tolerated at doses up to 0.2 mg/kg. There were no drug-related serious adverse events. No patient discontinued because of adverse events; however, two patients administered 0.33 mg/kg developed adverse reactions immediately after infusion of the study drug. No other patients were treated at this dose level. The most frequent (>35% of patients) treatment-emergent adverse events were diarrhea, fatigue, pyrexia, vomiting, and nausea. Most adverse events were mild or moderate and resolved the same day without sequelae. Eight (27%) patients developed WHO grade 3 or 4 OM during the study; seven of these patients received high-dose melphalan as a conditioning regimen., Conclusion: Velafermin was well tolerated by autologous PBSCT patients at doses up to 0.2 mg/kg.

Amgen is developing a recombinant human form of keratinocyte growth factor (rHu-KGF) called palifermin [AMJ 9701]. Keratinocyte growth factor (KGF, fibroblast growth factor 7, FGF-7) is a form of an endogenous epithelial tissue growth factor that stimulates the growth of cells on the surface of the gastrointestinal tract. Palifermin is being developed for oral mucositis (stomatitis), for which it is undergoing review by the US FDA.At BioSquare-2004, Biovitrum stated that it has entered into an agreement with Amgen, under which Biovitrium has co-promotion rights to palifermin in Nordic countries, including Scandinavia and Iceland. Amgen also plans to investigate the efficacy and safety of palifermin in patients with oral mucositis associated with other forms of chemotherapy. Amgen has stated that palifermin is also undergoing phase II trials in patients with solid tumours.

Keratinocyte growth factor (KGF) is a paracrine-acting, epithelial mitogen produced by cells of mesenchymal origin. It is a member of the fibroblast growth factor (FGF) family, and acts exclusively through a subset of FGF receptor isoforms (FGFR2b) expressed predominantly by epithelial cells. The upregulation of KGF after epithelial injury suggested it had an important role in tissue repair. This hypothesis was reinforced by evidence that intestinal damage was worse and healing impaired in KGF null mice. Preclinical data from several animal models demonstrated that recombinant human KGF could enhance the regenerative capacity of epithelial tissues and protect them from a variety of toxic exposures. These beneficial effects are attributed to multiple mechanisms that collectively act to strengthen the integrity of the epithelial barrier, and include the stimulation of cell proliferation, migration, differentiation, survival, DNA repair, and induction of enzymes involved in the detoxification of reactive oxygen species. KGF is currently being evaluated in clinical trials to test its ability to ameliorate severe oral mucositis (OM) that results from cancer chemoradiotherapy. In a phase 3 trial involving patients who were treated with myeloablative chemoradiotherapy before autologous peripheral blood progenitor cell transplantation for hematologic malignancies, KGF significantly reduced both the incidence and duration of severe OM. Similar investigations are underway in patients being treated for solid tumors. On the basis of its success in ameliorating chemoradiotherapy-induced OM in humans and tissue damage in a variety of animal models, additional clinical applications of KGF are worthy of investigation.

Purpose: To evaluate the safety of recombinant human keratinocyte growth factor (KGF) when administered with fluorouracil (FU) in patients with metastatic colorectal cancer., Patients and Methods: Patients (N = 81) received KGF by intravenous (IV) bolus on days 1 to 3, followed by FU 425 mg/m2/d IV bolus plus leucovorin 20 mg/m2/d IV on days 4 to 8. KGF dose levels were 1, 10, 20, 40, 60, and 80 microg/kg/d. A randomized, placebo-controlled design was employed (2:1 randomization of KGF to placebo). Oral mucositis was assessed by examination on days 1, 4, 8, 15, and 28. In addition, patients provided daily assessments of oral symptoms using a self-administered questionnaire., Results: Skin and oral events occurred in 13 of 18 patients (eight patients, grade 1; four patients, grade 2; and one patient, grade 3) treated with 60 and 80 microg/kg of KGF and three of 11 patients treated with 40 microg/kg (grade 1). These symptoms were dose limiting in three cases (ie, in two of 10 patients treated with 80 microg/kg and in one of eight patients treated with 60 microg/kg). The frequency of grade 2 to 4 mucositis was 43% in patients treated with KGF, compared with 67% in patients treated with placebo (P =.06). Patient self-assessments of oral pain and clinical assessments of mucositis showed good correlation (Kendall's tau = 0.75)., Conclusion: KGF is generally well tolerated when administered IV at doses up to 40 microg/kg/d for 3 days before a 5-day course of FU plus leucovorin. A clinically meaningful biologic effect was also suggested in that patients treated with the epithelial growth factor KGF had a lower rate of grade 2 to 4 mucositis than did patients treated with placebo.

This review outlines the current status of anti-angiogenic treatment, with emphasis on clinical trials. In pathological growth, vessels become hyperstimulated and dysfunctional, due to overexpression of angiogenic growth factors, such as vascular endothelial growth factor (VEGF). Thus, various anti-angiogenic substances have been developed that neutralize VEGF; others aim to reduce the capacity of the cells to respond to this factor. In addition, substances that are inhibitors of matrix metalloproteinases or agents that induce programmed cell death (apoptosis) of endothelial cells are being tested. Another class of angiogenesis inhibitors includes those that already are in clinical use but on other indications. The National Cancer Institute (NCI) in the USA provides information on on-going clinical trials, which are being conducted on patients suffering from different solid tumor diseases, such as cancer of the colon, lung, prostate and breast. For treatment regimens with anti-angiogenic substances it is important to consider the appropriate dosing and dose interval. The clinical trials have in many instances only recently been initiated and it is premature to predict the outcome, especially as patients in the trials suffer from seriously progressive disease that has previously been treated and found to be therapy-resistant. In many cases combination therapy with an anti-angiogenic substance together with radiation, chemotherapy or other types of conventional tumor treatment, appears promising.

The fibroblast growth factor (FGF) family of signalling molecules and its receptors (FGFRs) contribute to normal developmental and physiological processes. However, the subversion of this powerful growth stimulatory pathway has been implicated in the generation of a variety of pathological conditions. This review focuses on the role of FGF/FGFRs in cancer. The case will be made that this signalling pathway is associated with and functionally important for the growth of some human tumours. As such, FGF/FGFRs can be viewed as rational therapeutic oncology targets and strategies used to inhibit these molecules are discussed. The therapeutic exploitation of tumour-associated FGFR expression to deliver toxins or antiproliferative signals to tumour cells is also reviewed, as is the use of FGFs as protein therapeutics to alleviate the side effects of cancer therapy.

Background: The angiogenic response to myocardial ischemia can be augmented in animal models by gene transfer with the use of a replication defective adenovirus (Ad) containing a human fibroblast growth factor (FGF) gene., Methods and Results: The objectives of the Angiogenic GENe Therapy (AGENT) trial were to evaluate the safety and anti-ischemic effects of 5 ascending doses of Ad5-FGF4 in patients with angina and to select potentially safe and effective doses for subsequent study. Seventy-nine patients with chronic stable angina Canadian Cardiovascular Society class 2 or 3 underwent double-blind randomization (1:3) to placebo (n=19) or Ad5-FGF4 (n=60). Safety evaluations were performed at each visit and exercise treadmill testing (ETT) at baseline and at 4 and 12 weeks. Single intracoronary administration of Ad5-FGF4 seemed to be safe and well tolerated with no immediate adverse events. Fever of <1-day duration occurred in 3 patients in the highest-dose group. Transient, asymptomatic elevations in liver enzymes occurred in 2 patients in lower-dose groups. Serious adverse events during follow-up (mean, 311 days) were not different between placebo and Ad5-FGF4. Overall, patients who received Ad5-FGF4 tended to have greater improvements in exercise time at 4 weeks (1.3 versus 0.7 minutes, P=NS, n=79). A protocol-specified, subgroup analysis showed the greatest improvement in patients with baseline ETT < or =10 minutes (1.6 versus 0.6 minutes, P=0.01, n=50)., Conclusions: Results show evidence of favorable anti-ischemic effects with Ad5-FGF4 compared with placebo, and it appears to be safe. Angiogenic gene transfer with Ad5-FGF4 shows promise as a new therapeutic approach to the treatment of angina pectoris.

Background: Trafermin (basic fibroblast growth factor) has been shown to reduce infarct volume in acute ischemic stroke models, and to promote functional recovery and new synapse formation when given to animals with completed cerebral infarction. A previous study in acute stroke patients suggested that trafermin was safe and well tolerated when given over a 3-hour period over a wide dose range., Methods and Results: Double-blind, parallel group, placebo-controlled trial of a single 24-hour intravenous infusion of trafermin. Patients having onset of stroke symptoms within 6 h and a baseline score of >/=7 on the NIH Stroke Scale (>/=2 motor) were randomized to receive 5 or 10 mg of trafermin or placebo intravenously infused over 24 h. The primary efficacy outcome was a categorized combination of the Barthel and Rankin scales assessed at 90 days. A total of 286 patients had been enrolled at 55 sites in 11 countries when the sponsor directed that enrollment be stopped because an interim analysis of efficacy data predicted too small a chance of demonstrating a statistically significant benefit after recruitment of the planned 900 patients. The 5-mg group showed a slight but nonsignificant advantage over placebo (OR 1.2, 95% CI 0.72-2.00, p = 0.48); the 10-mg group showed a nonsignificant disadvantage (OR 0.74, 95% CI 0.44-1.22, p = 0.24). Mortality rates at 90 days were 17% in the 5-mg group, 24% in the 10-mg group and 18% in the placebo group. Treatment with trafermin was associated with an increased leukocytosis and a decrease in blood pressure: mean decrease in systolic blood pressure from baseline was 19 mm Hg in the 5-mg group, 22 mm Hg in the 10-mg group and 8 mm Hg in the placebo group. In a post hoc subgroup analysis, patients in the 5-mg group treated more than 5 h after the onset of symptoms showed an apparent advantage over placebo (OR 2.1, 95% CI 1.00-4.41, p = 0.044; after age adjustment: OR 1.9, 95% CI 0.91-4.13, p = 0.08)., Conclusions: With the proper treatment regimen, trafermin can likely be given safely to stroke patients. The 5-mg dose showed a trend toward a treatment advantage. The ideal time window for this agent may exceed 5 h. This may open new avenues for acute stroke therapy, aiming at enhancing recovery mechanisms rather than immediate neuroprotection., (Copyright 2002 S. Karger AG, Basel)

Therapeutic angiogenesis based on the administration of growth factors with angiogenic activity allows enhancement of collateral vessels able to palliate insufficient tissue perfusion secondary to obstruction of native arteries. At present, this type of therapy is addressed to patients that fail to respond to conventional treatment (surgical or percutaneous revascularization). The most extensively investigated angiogenic growth factors are vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF). These cytokines can be administered either as recombinant proteins or as the genes encoding for these proteins. Both approaches have pros and cons that are under investigation in animal models and in clinical studies. Although clinical trials consist so far of small, often non-randomized series, preliminary results are promising. For example, administration of VEGF or FGF has been associated to objective evidence of increased tissue perfusion in patients with myocardial ischemia, and to a significant improvement of pain and ischemia in patients with peripheral arterial disease. Contrarily to expected, these interventions have been associated to scant adverse side effects, although larger clinical trials will be necessary in order to prove the safety and effectiveness of these interventions. Nevertheless, it seems clear that it is feasible to induce effective therapeutic angiogenesis in selected patients without significant associated toxicity.

About 600,000 people in the United States are estimated to be affected by venous ulcers. The cornerstone of care of chronic venous ulcers involves the application of compression bandages. Other therapies include treatment of associated infection, treatment for edema and inflammation, and debridement when necessary. Repifermin, a recombinant human KGF-2 (fibroblast growth factor-10), exerts a proliferative effect on epithelial cells, in vitro and in vivo, and has been shown to accelerate wound healing in several experimental animal models. A randomized, double-blind, parallel-group, placebo-controlled, multicenter study was conducted to evaluate the safety and efficacy of topical repifermin treatment, for 12 weeks, in the healing of chronic venous ulcers in 94 patients. Repifermin was shown to accelerate wound healing, with significantly more patients achieving 75% wound closure with repifermin than with placebo. The treatment effect appeared more marked for a subgroup of patients with initial wound areas < or = 15 cm2 and wound ages of < or = 18 months. A longer duration of treatment (e.g., 26 weeks) may allow better differentiation of the benefit of repifermin compared with placebo, particularly with respect to complete wound closure. The safety assessment showed that repifermin was well tolerated.

Tumor-induced osteomalacia (TIO) is one of the paraneoplastic diseases characterized by hypophosphatemia caused by renal phosphate wasting. Because removal of responsible tumors normalizes phosphate metabolism, an unidentified humoral phosphaturic factor is believed to be responsible for this syndrome. To identify the causative factor of TIO, we obtained cDNA clones that were abundantly expressed only in a tumor causing TIO and constructed tumor-specific cDNA contigs. Based on the sequence of one major contig, we cloned 2,270-bp cDNA, which turned out to encode fibroblast growth factor 23 (FGF23). Administration of recombinant FGF23 decreased serum phosphate in mice within 12 h. When Chinese hamster ovary cells stably expressing FGF23 were s.c. implanted into nude mice, hypophosphatemia with increased renal phosphate clearance was observed. In addition, a high level of serum alkaline phosphatase, low 1,25-dihydroxyvitamin D, deformity of bone, and impairment of body weight gain became evident. Histological examination showed marked increase of osteoid and widening of growth plate. Thus, continuous production of FGF23 reproduced clinical, biochemical, and histological features of TIO in vivo. Analyses for recombinant FGF23 products produced by Chinese hamster ovary cells indicated proteolytic cleavage of FGF23 at the RXXR motif. Recent genetic study indicates that missense mutations in this RXXR motif of FGF23 are responsible for autosomal dominant hypophosphatemic rickets, another hypophosphatemic disease with similar features to TIO. We conclude that overproduction of FGF23 causes TIO, whereas mutations in the FGF23 gene result in autosomal dominant hypophosphatemic rickets possibly by preventing proteolytic cleavage and enhancing biological activity of FGF23.

Topical application of FGF (fibroblast growth factor), a potent mitogen for mesodermal and neuroectodermal cells, was given to promote the healing of tympanic membrane perforations in rats. Calibrated tympanic membrane perforations were performed in 30 rats. At day 0, each rat received 40 microliters of placebo in the right ear and 40 microliters of a solution containing FGF in the left ear at different concentrations. The quality of healing was observed by otomiscroscopy and by light microscopic examination of histological sections. The mean time of closure was significantly shorter in ears receiving an amount of 400 ng FGF (6.1 days), as compared to non-treated ears (8.8 days). Using a higher dose of FGF, the promoting effect was counterbalanced by a high rate of myringitis. Using a dose of 200 ng of FGF, no difference was noticed between placebo group and FGF group.