While prophylactic human papillomavirus (HPV) vaccination exists, women are still developing cervical intraepithelial neoplasia (CIN) grade 2 or 3 for which an immunotherapeutic, non-surgical, approach may be effective. The primary aim was to assess the efficacy of tipapkinogen sovacivec (TS) vaccine in achieving histologic resolution of CIN2/3 associated with high risk (HR) HPV types.
Women 18 years and older who had confirmed CIN2/3 were enrolled in a randomized, double blind, placebo-controlled phase II trial and assigned to drug in a 2:1 ratio (vaccine:placebo). The primary endpoint occurred at month 6 when the excisional therapy was performed; cytology and HR HPV typing were performed at months 3, 6 and every six months through month 30. The safety population included all patients who received at least one dose of study drug.
Of the 129 women randomized to vaccine and 63 to placebo, complete resolution was significantly higher in the vaccine group than placebo for CIN 2/3 regardless of the 13 HR HPV types assayed (24% vs. 10%, p < 0.05); as well as for only CIN 3 also regardless of HR HPV type (21% vs. 0%, p < 0.01). Irrespective of baseline HPV infection, viral DNA clearance was higher in the vaccine group compared to placebo (p < 0.01). The vaccine was well tolerated with the most common adverse events being injection site reactions.
The TS vaccine provides histologic clearance of CIN 2/3 irrespective of HR HPV type in one third of subjects and is generally safe through 30 months.