Efficacy and safety of RD2 Ver.02, a whole blood clot therapy, coupled with a minimally invasive procedure in pilonidal sinus: a phase II study

Background: PNS is caused by an infection in the sacrococcygeal area triggered by hair particle accumulation in skin tunnels, resulting in infection. Surgical options range from simple excision to complex flap constructions. Primary wound healing failure and recurrence rates contribute to the burden of PNS. RD2 Ver.02, a novel autologous whole-blood clot product, demonstrated safety and efficacy in treating complex cutaneous wounds and was investigated for the management of PNS. Methods: A Phase II open-label, pilot, single-arm prospective study was conducted from May 2021 to May 2023 (Ethics Committee approval #7952-20). Patients with PNS underwent a minimally invasive trephine procedure under local anesthesia followed by RD2 Ver.02 instillation into the cavity. Primary healing was assessed at 3, 6, and 12 months. Secondary outcomes included the collection of adverse events. Results: Overall, 51 patients participated in the study. At 3 months, 42/51 healed (82.4%), 7/51 (13.7%) were granulating but not completely healed, and 2/51 (3.9%) failed to heal. At 6 and 12 months, 46/51 (90.2%) and 42/51 (82.4%) achieved complete healing, respectively. At 6 months, two PNSs recurred after initial healing and an additional four instances of PNS recurrence observed in 12 months, so a total of recurrence in six patients (11.8%). There were five adverse events (AEs) with no severe adverse events. Conclusion: RD2 Ver.02 is a safe and effective treatment of PNS when coupled with a minimally invasive trephine PNS procedure. Further comparative studies are needed to fully assess the role of this novel therapy for PNS. Graphical abstract: (Figure presented.)