Therapeutic HPV-16 Vaccination for the Treatment of Anal Dysplasia

Rationale: Since the introduction of combination antiretroviral therapy (cART), human immunodeficiency virus (HIV)-related morbidity and mortality have considerably decreased. However, as a result of the significantly prolonged life span of HIV-positive patients, new causes of morbidity and mortality have become evident. In particular, anal cancer incidence has increased dramatically in HIV-positive men. Like cervical cancer, anal cancer is causally linked to infections with high-risk papillomaviruses (HPV), and is preceded by cancer precursor lesions: anal intraepithelial neoplasia (AIN). Over 90% of HIV-positive MSM have persisting anal HPV infection, in 88% of patients high-risk HPV is present, and high-grade disease (AIN 2 or 3, HG AIN) is present in 25-52% of all HIV+ MSM. The majority of HG AIN is caused by HPV type 16. As in cervical intraepithelial neoplasia, early diagnosis and treatment of AIN have been advocated to prevent malignancy.

Several treatment options exist for AIN, but success rates are disappointingly low. An alternative strategy might be therapeutic HPV vaccination. In women with vulvar intraepithelial neoplasia (VIN), a condition with a comparable pathogenesis, therapeutic vaccination with a synthetic long-peptide vaccine SLP-HPV-01® , consisting of a mix of long peptides from the HPV-16 viral oncoproteins E6 and E7, was well tolerated, and proved to be effective in a high percentage of women, with a durable response, and induction of HPV-16-specific immunity.

Objective: The objective of the current proposal is to assess, in a phase 1/2 study, the safety and efficacy of this synthetic vaccine SLP-HPV-01® in HIV+ men with CD4 counts > 350 x 10E6/l and intra-anal high-grade, HPV16 positive AIN, who failed on previous treatment.

Study population: HIV-positive MSM with a CD4 count > 350 cells/ul with HPV16-induced intra-anal high-grade AIN (grade 2-3) that was resistant to, or recurred after conventional cauterization or other forms of local treatment.

During the past years the study group in the Academic Medical Center in Amsterdam has built a large cohort of well-characterized HIV-positive patients with histology-proven AIN. Material has been stored of these patients and their lesions. Those patients with AIN resistant to previous treatment will be identified. The causative HPV type will be determined in stored biopsies of these patients, using microdissection (LCM) and in-situ PCR. Only patients with HPV-16-induced lesions (the majority of patients) will be eligible for the current study.

Study design: : The first phase of the study is a dose-response study, with four different dosage schedules (1,5,10; 5,10,20; 10,20,40 and 40,40,40,40 μg of SLP-HPV-01®, administered intradermally with a three-week interval), each dosage schedule with or without the co-administration of pegylated interferon-α (Pegintron 1 μg/kg s.c.) at the day of vaccine administration. Each vaccination schedule is to be tested in 5 patients.

The vaccination schedule that induces in HIV-positive MSM the best HPV16-specific response compared to that of the women with VIN in our previous study, is considered the optimal schedule. The size of this dose group will be increased to a total of 20 patients by treating an additional 15 patients.

Intervention: Patients will be vaccinated 3 or 4 times with a 3-week interval with the SLP-HPV-01® vaccine.

High-resolution anoscopy (HRA) will be performed at inclusion, and repeated at 3, 6,12 and 18 months. The transformation zone will be photographed at each visit. Detailed photos plus biopsies of lesion sites will be obtained. From venous blood samples PBMCs will be obtained before the first (pre), 3 weeks after the first vaccination (post-1), 3 weeks after the second vaccination (post-2), 3 weeks after the third vaccination (post-3) and if applicable 3 weeks after the fourth vaccination (post-4).

Endpoints: The primary clinical end points will be both toxicity/ safety, and the regression of the lesions at 3, 6 and 12 months, as assessed by HRA, with biopsies taken of lesion sites.

Secondary endpoints are regression of lesions at 18 months and HPV16-specific immunity in blood will be measured: i.e. ELISPOT (IFNg) for ex-vivo detection of antigen-specific responses and multiparametric intracellular cytokine/extracellular activation marker staining to determine the type (CD4+ and/or CD8+) and function (activation status and/or cytokines) of T-cells that respond.