RESUMO
BACKGROUND: Connective tissue growth factor (CTGF) is a matricellular protein that plays a key role in wound healing and scar formation. Inhibition of CTGF by a specific antisense oligonucleotide significantly reduced scarring and fibrosis in animal models. This study examined whether an antisense oligonucleotide that inhibits human CTGF expression could reduce the severity of hypertrophic scar formation in patients following surgical revision of preexisting breast scars. METHODS: This study was a 24-week multicenter, randomized, double-blind, within-subject, placebo-controlled phase 2b study evaluating the efficacy and safety of PF-06473871 in 2 regimens of either 3 or 4 intradermal injections (postsurgery weeks 2, 5, 8, and 11) of 5 mg/cm adjacent to the new surgical incision. One hundred subjects with bilateral hypertrophic scars resulting from prior breast surgery were randomized. Efficacy was determined by the Patient and Observer Scar Assessment Scale (POSAS). RESULTS: The Physician/Observer POSAS overall opinion score at (week 24) for the 4-injection regimen demonstrated a statistically significant (P = 0.022) treatment difference from placebo of 0.68, and the treatment difference for the 3-injection regimen was nonsignificant (P = 0.4). Physician evaluation of scar severity at (week 24) with the photo-guide in the 4-injection regimen had a significant reduction (point estimate of treatment difference of 0.43 favoring PF-06473871). The surgical effect was approximately 2.0 at week 24 and was nearly 3 times greater than the treatment effect. Patient evaluations using the POSAS and photo-guide were not significantly improved with either dose regimen. PF-06473871 was generally well tolerated systemically and locally. CONCLUSION: The 4-dose regimen of PF-06473871 provided statistically significant improvement, inhibiting severity of hypertrophic scar formation based on physician assessment. However, the effect of revision surgery alone is significant and may dominate the treatment effect of PF-06473871.
RESUMO
BACKGROUND: Connective tissue growth factor (CTGF) levels are up-regulated in wounded skin and are thought to play a major role in scar formation. An antisense oligonucleotide targeting CTGF was evaluated in adult patients undergoing hypertrophic scar revision surgery, to determine effects on reducing the severity of subsequent scars. METHODS: In a randomized, double-blind, within-subject, placebo-controlled study, 23 female subjects (aged 28 to 55 years) with bilateral, symmetric, hypertrophic surgical scars of the breast underwent scar revision surgery. The resulting breast incisions were randomized to receive EXC 001 (5 mg/cm) or placebo injected intradermally at postsurgery weeks 2, 5, 8, and 11. Scar severity assessments were performed at weeks 12 and 24 by an expert panel using blinded photographs, and by physicians and subjects using a scar scoring scale, the Patient and Observer Scar Assessment Scale. An assumption of the design is that within-subject variance would be small and that whatever within-subject variance there was would be controlled through the randomization process. RESULTS: EXC 001 significantly reduced scar severity at both 12 and 24 weeks after scar revision surgery in all three measures (expert panel and physician Patient and Observer Scar Assessment Scale, p < 0.001; Patient and Observer Scar Assessment Scale, p < 0.003). CONCLUSIONS: This study provided positive preliminary data that intradermal injection of EXC 001 produced a significant reduction in severity of postsurgical skin scars, as measured by physicians, subjects, and an expert panel. This study provided evidence that suppression of CTGF could be a viable strategy for hypertrophic scar reduction therapy and that further study of the antisense oligonucleotide EXC 001 was indicated. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.
