PN HPT™ and Striae Albae-Exploratory Interim Analysis of a Randomised Prospective Study

Introduction: The outcomes of striae albae remodelling are currently disappointing. Replenishing the fibroblast pool of nucleotide precursors through passive exposure to Polynucleotides Highly Purified Technology (PN HPT™) facilitates the dermal production of new fibres. The manuscript reports on the outcomes of a prospective study with an intradermal PN HPT™-based medical device. Methods: Intra-subject-controlled randomised real-world study to evaluate the efficacy and safety of a medical device containing 20 mg/mL of PN HPT™ (functional ingredient) intradermal gel as therapy for moderate-to-severe striae albae. Based on a preliminary sample size assessment, the study estimated the need to enrol at least 65 mature albae from 18-to-55-year-old male and female subjects seeking ambulatory treatment (mean age: 34.1 ± 10.65). Up to eight symmetrical striae albae in the target areas (breast, abdomen, buttocks, thighs) per enrolled subject underwent randomisation into the two parallel “PN HPT™ intradermal infiltration” active group and “no-treatment striae albae” intra-subject control group. Actively treated striae albae underwent a four-session intradermal therapy cycle with the PN HPT™ device. Comparative efficacy assessments, performed at the two final evaluation visits by independent evaluators: Width of actively treated and untreated control striae albae (digital calliper). Global Aesthetic Improvement Scale (GAIS) outcomes (by investigators and subjects, respectively; assessments on digital photographic documentation). Width and wrinkling of actively treated and control striae albae (quantitative Antera 3D CS skin imaging technology). Results: The digital-calliper-assessed width for the exploratory sample of the 44 actively treated striae albae (29 control striae) decreased, on average, from 4.6 ± 2.31 at the V1 baseline visit to 2.7 ± 1.42 at V5 (first follow-up visit) one month after the last PN HPT™ intradermal infiltration at V4 (–40.8% vs. baseline, p <0.01). In a subset of 17 striae (7 subjects), the mean digital-calliper-assessed width was still a significant 2.0 ± 0.94 at the final V6 follow-up visit, six months after V1 and three months after V4 (–54.5% vs control striae albae at V6, p <0.05). At the V5 assessment, three months after V1 and one month and a half after V4, investigators and treated subjects reported average GAIS scores of 3.8 ± 0.51 (median, 4.0) and 4.0 ± 0.66 (median, 4.0) out of 5.0 as GAIS maximum score for both. The occasional mild local pain and irritation at the injection site, expected and known in the previous PN HPT™ literature, were of no clinical significance and rapidly transitory. Discussion: PN HPT™ are an innovative option with a solid rationale for treating mature striae albae. The efficacy outcomes of PN HPT™ dermal infiltrations appear noteworthy, with excellent safety and ease of use, confirming the previous results. However, waiting for complete results and confirmation by other controlled studies is prudent.