Randomized clinical trial of imiquimod: an adjunct to treating cervical dysplasia

Randomized Phase II Trial of Imiquimod with or without 9-Valent HPV Vaccine versus Observation in Patients with High-grade Pre-neoplastic Cervical Lesions (NCT02864147)

PURPOSE

We report the results of a randomized phase II trial of imiquimod, a topical immune-response modulator versus imiquimod plus a 9-valent human papillomavirus (HPV) vaccine (9vHPV) versus clinical surveillance in cervical intraepithelial neoplasia (CIN2/3) patients.

PATIENTS AND METHODS

We randomly allocated 133 patients with untreated CIN2/3 in equal proportions to a 4-month treatment with self-applied vaginal suppositories containing imiquimod (Arm B) or imiquimod plus a 9vHPV (Arm C) versus clinical surveillance (Arm A). The main outcome was efficacy, defined as histologic regression to CIN1 or less. Secondary outcomes were HPV clearance and tolerability. Exploratory objectives included the comparison of cervical CD4/CD8 T-cell infiltration at baseline, mid-study, and posttreatment by flow cytometry among study arms.

RESULTS

Of the 114 evaluable patients 77% and 23% harbored CIN2 and CIN3, respectively. Regression to CIN1 or less was observed in 95% of patients in the imiquimod group (Arm B) compared with 79% in the control/surveillance (Arm A); P = 0.043 and 84% in the imiquimod+9vHPV group (Arm C; P = 0.384 vs. Arm A). Neither of the treatment-arm differences from Arm A reached the prespecified α = 0.025 significance level. No significant differences were noted in the secondary outcome of rate of HPV clearance. The number of tissue-resident memory CD4/CD8 T cells in cytobrush samples demonstrated a >5-fold increase in Arm B/imiquimod when compared with Arm A/surveillance (P < 0.01). In contrast, there was no significant difference in T-cell responses among participants in Arm C when compared with Arm A. Imiquimod treatment was well tolerated.

CONCLUSIONS

Although imiquimod induced a higher regression to CIN1 or less and significant increases in CD4/CD8 T cells infiltrating the cervix, it did not meet its prespecified statistical outcome for efficacy. A higher regression rate than expected was observed in the surveillance arm of this prospective trial. Future clinical trials with imiquimod targeting CIN3 patients are warranted.

Imiquimod Is Effective in Reducing Cervical Intraepithelial Neoplasia: A Systematic Review and Meta-Analysis

INTRODUCTION

Topical Imiquimod is an immune response modifier approved for the off-label use of vulvar intraepithelial neoplasia. We conducted this systematic review and meta-analysis to investigate the efficacy and safety of Imiquimod in treating cervical intraepithelial neoplasia (CIN) and human papillomavirus (HPV)-positive patients.

METHODS

The study was prospectively registered (CRD420222870) and involved a comprehensive systematic search of five medical databases on 10 October 2022. We included articles that assessed the use of Imiquimod in cervical dysplasia and HPV-positive patients. Pooled proportions, risk ratios (RRs), and corresponding 95% confidence intervals (CIs) were calculated using a random effects model to generate summary estimates. Statistical heterogeneity was assessed using I2 tested by the Cochran Q tests.

RESULTS

Eight articles reported on 398 patients who received Imiquimod out of 672 patients. Among CIN-2-3 patients, we observed a pooled regression rate of 61% (CI: 0.46-0.75; I2: 77%). When compared, Imiquimod was inferior to conization (RR: 0.62; CI: 0.42-0.92; I2: 64%). The HPV clearance rate in women who completed Imiquimod treatment was 60% (CI: 0.31-0.81; I2: 57%). The majority of side effects reported were mild to moderate in severity.

CONCLUSIONS

Our findings indicate that topical Imiquimod is safe and effective in reducing cervical intraepithelial neoplasia and promoting HPV clearance. However, it was found to be inferior compared to conization. Imiquimod could be considered a potential medication for high-grade CIN patients and should be incorporated into guidelines for treating cervical dysplasia.

The efficacy of topical imiquimod in high-grade cervical intraepithelial neoplasia: A systematic review and meta-analysis

OBJECTIVE

A major side effect of cervical excision for high-grade cervical intraepithelial neoplasia (CIN) is premature birth. A non-invasive treatment for reproductive age women is warranted. The aim of the present study was to determine the efficacy of topical imiquimod in the treatment of high-grade CIN, defined as a regression to ≤CIN 1, and to determine the clearance rate of high-risk human papillomavirus (hr-HPV), compared with surgical treatment and placebo.

METHODS

Databases were searched for articles from their inception to February 2023.The study protocol number was INPLASY2022110046. Original studies reporting the efficacy of topical imiquimod in CIN 2, CIN 3 or persistent hr-HPV infections were included. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist.

RESULTS

Five studies were included (n = 463). Histological regression to ≤CIN 1 was 55% in imiquimod versus 29% in placebo, and 93% in surgical treatment. Imiquimod-treated women had a greater odds of histological regression to ≤CIN 1 than placebo (odds ratio [OR] 4.17, 95% confidence interval [CI] 2.03-8.54). In comparison to imiquimod, surgical treatment had an OR of 14.81(95% CI 6.59-33.27) for histological regression to ≤CIN 1. The hr-HPV clearance rate was 53.4% after imiquimod and 66% after surgical treatment (95% CI 0.62-23.77).

CONCLUSIONS

The histological regression rate is highest for surgical treatment followed by imiquimod treatment and placebo.

Feasibility of 5-fluorouracil and imiquimod for the topical treatment of cervical intraepithelial neoplasias (CIN) 2/3

OBJECTIVES

To determine the feasibility (as measured by tolerability and safety) and efficacy of topical 5-fluorouracil (5-FU) and imiquimod for the treatment of cervical intraepithelial neoplasia (CIN) 2/3.

METHODS

This pilot prospective study was conducted in women aged 18-45 years with p16+ CIN 2/3. Participants underwent an 8-week alternating regimen of self-applied 5% 5-FU on weeks 1, 3, 5, and 7 and physician-applied imiquimod on weeks 2, 4, 6, and 8. Adverse events (AEs) were collected by symptom diary and clinical exam. Feasibility was measured by tolerability and safety (AEs) of the study intervention. Tolerability was assessed as the number of participants able to apply 50% or more of the treatment doses. The safety outcome was calculated as the number of participants who experienced "specified AEs" defined as possibly, probably, or definitely related grade 2 or worse AE or grade 1 genital AEs (blisters, ulcerations, or pustules) lasting more than 5 days. The efficacy of the intervention was determined by histology and high-risk human papillomavirus (hrHPV) testing was done after treatment.

RESULTS

The median age of the 13 participants was 27 ± 2.9 years. Eleven (84.61%) participants applied 50% or more of the treatment. All participants reported grade 1 AEs; 6 (46.15%) reported grade 2 AEs; and 0 reported grade 3/4 AEs. Three (23.08%) participants had specified AEs. Histologic regression to normal or CIN 1 among those completing 50% or more of the treatment doses was observed in 10 (90.91%) participants, and 7 (63.63%) tested negative for hr-HPV at the end of the study.

CONCLUSIONS

Topical treatment for CIN 2/3 with 5-FU/imiquimod is feasible, with preliminary evidence of efficacy. Topical therapies need further investigation as adjuncts or alternatives to surgical therapy for CIN 2/3.

Recent advances in treating female genital human papillomavirus related neoplasms with topical imiquimod

Human papillomavirus (HPV) encompasses a group of viruses that infect the skin and mucous membranes. In the presence of certain factors, persistent infection with high-risk HPVs can trigger a process of neoplastic transformation. Imiquimod is a topical agent that acts as a Toll-like receptor 7/8 agonist, stimulating the innate and adaptive immune system to exert antitumor and antiviral effects. It has been approved for the treatment of various skin conditions, however, its efficacy and safety in the management of HPV-related-neoplasms of the lower genital tract, such as vulvar, vaginal, and cervical neoplasia, are still under investigation. This review summarizes the current evidence on the use of imiquimod for the treatment of HPV-induced lesions of the female lower genital tract, focusing on its indications, mechanisms of action, outcomes, and predictors of response.

Imiquimod for Cervical and Vaginal Intraepithelial Neoplasia: A Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the treatment efficacy and the risk of adverse events of imiquimod for cervical intraepithelial neoplasia (CIN) and vaginal intraepithelial neoplasia (VAIN), compared with placebo or no intervention.

DATA SOURCES

We searched Cochrane, PubMed, ISRCTN registry, ClinicalTrials.gov , and the World Health Organization International Clinical Trials Registry Platform up to November 23, 2022.

METHODS OF STUDY SELECTION

We included randomized controlled trials and prospective nonrandomized studies with control arms that investigated the efficacy of imiquimod for histologically confirmed CIN or VAIN. The primary outcomes were histologic regression of the disease (primary efficacy outcome) and treatment discontinuation due to side effects (primary safety outcome). We estimated pooled odds ratios (ORs) of imiquimod, compared with placebo or no intervention. We also conducted a meta-analysis of the proportions of patients with adverse events in the imiquimod arms.

TABULATION, INTEGRATION, AND RESULTS

Four studies contributed to the pooled OR for the primary efficacy outcome. An additional four studies were available for meta-analyses of proportions in the imiquimod arm. Imiquimod was associated with increased probability of regression (pooled OR 4.05, 95% CI 2.08-7.89). Pooled OR for CIN in the three studies was 4.27 (95% CI 2.11-8.66); results of one study were available for VAIN (OR, 2.67, 95% CI 0.36-19.71). Pooled probability for primary safety outcome in the imiquimod arm was 0.07 (95% CI 0.03-0.14). The pooled probabilities (95% CI) of secondary outcomes were 0.51 (0.20-0.81) for fever, 0.53 (0.31-0.73) for arthralgia or myalgia, 0.31 (0.18-0.47) for abdominal pain, 0.28 (0.09-0.61) for abnormal vaginal discharge or genital bleeding, 0.48 (0.16-0.82) for vulvovaginal pain, and 0.02 (0.01-0.06) for vaginal ulceration.

CONCLUSION

Imiquimod was found to be effective for CIN, whereas data on VAIN were limited. Although local and systemic complications are common, treatment discontinuation is infrequent. Thus, imiquimod is potentially an alternative therapy to surgery for CIN.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42022377982.

Importance of the Immune Microenvironment in the Spontaneous Regression of Cervical Squamous Intraepithelial Lesions (cSIL) and Implications for Immunotherapy

Cervical high-grade squamous intraepithelial lesions (cHSILs) develop as a result of a persistent high-risk human papilloma virus (hrHPV) infection. The natural course of cHSIL is hard to predict, depending on a multitude of viral, clinical, and immunological factors. Local immunity is pivotal in the pathogenesis, spontaneous regression, and progression of cervical dysplasia; however, the underlying mechanisms are unknown. The aim of this review is to outline the changes in the immune microenvironment in spontaneous regression, persistence, and responses to (immuno)therapy. In lesion persistence and progression, the immune microenvironment of cHSIL is characterized by a lack of intraepithelial CD3+, CD4+, and CD8+ T cell infiltrates and Langerhans cells compared to the normal epithelium and by an increased number of CD25+FoxP3+ regulatory T cells (Tregs) and CD163+ M2 macrophages. Spontaneous regression is characterized by low numbers of Tregs, more intraepithelial CD8+ T cells, and a high CD4+/CD25+ T cell ratio. A ‘hot’ immune microenvironment appears to be essential for spontaneous regression of cHSIL. Moreover, immunotherapy, such as imiquimod and therapeutic HPV vaccination, may enhance a preexisting pro-inflammatory immune environment contributing to lesion regression. The preexisting immune composition may reflect the potential for lesion regression, leading to a possible immune biomarker for immunotherapy in cHSILs.

Topical Imiquimod for the Treatment of High-Grade Squamous Intraepithelial Lesions of the Cervix: A Randomized Controlled Trial

Weekly topical treatment with imiquimod is effective in promoting regression of cervical high-grade squamous intraepithelial lesions.

OBJECTIVE:

To evaluate the histologic response rate of high-grade squamous intraepithelial lesions (HSIL) of the cervix after topical application of 5% imiquimod cream.

METHODS:

In this phase II trial, women with cervical HSIL (cervical intraepithelial neoplasia [CIN] 2–3) were randomly assigned to 250 mg of 5% imiquimod cream applied to the cervix weekly for 12 weeks, followed by loop electrosurgical excision procedure (LEEP) without preceding treatment. The sample size was calculated based on the HSIL regression rates previously reported by Grimm et al. The primary outcome was rate of histologic regression (to CIN 1 or less) in LEEP specimens. Prespecified secondary endpoints included surgical margin status and adverse events. Outcomes were stratified by human papillomavirus type and lesion grade (CIN 2 or CIN 3). Results were reported according to per protocol (PP) and intention-to-treat (ITT) analyses.

RESULTS:

Ninety women were enrolled: 49 in the experimental group and 41 in the control group. In the PP population, histologic regression was observed in 23 of 38 participants (61%) in the experimental group compared with 9 of 40 (23%) in the control group (P=.001). Surgical margins were negative for HSIL in 36 of 38 participants (95%) in the experimental group and 28 of 40 (70%) in the control group (P=.004). In the ITT population, rates of histologic regression also were significantly higher in the experimental group. Rates of adverse events in the experimental group were 74% (28/38) in the PP population and 78% (35/45) in the ITT population. Adverse events were mild, with abdominal pain being the most common. Three patients in the experimental group had grade 2 adverse events, including vaginal ulcer, vaginal pruritus with local edema, and moderate pelvic pain.

CONCLUSION:

Weekly topical treatment with imiquimod is effective in promoting regression of cervical HSIL.

CLINICAL TRIAL REGISTRATION:

ClinicalTrials.gov, NCT03233412.

Mechanisms of Macrophage Plasticity in the Tumor Environment: Manipulating Activation State to Improve Outcomes

Macrophages are a specialized class of innate immune cells with multifaceted roles in modulation of the inflammatory response, homeostasis, and wound healing. While developmentally derived or originating from circulating monocytes, naïve macrophages can adopt a spectrum of context-dependent activation states ranging from pro-inflammatory (classically activated, M1) to pro-wound healing (alternatively activated, M2). Tumors are known to exploit macrophage polarization states to foster a tumor-permissive milieu, particularly by skewing macrophages toward a pro-tumor (M2) phenotype. These pro-tumoral macrophages can support cancer progression by several mechanisms including immune suppression, growth factor production, promotion of angiogenesis and tissue remodeling. By preventing the adoption of this pro-tumor phenotype or reprogramming these macrophages to a more pro-inflammatory state, it may be possible to inhibit tumor growth. Here, we describe types of tumor-derived signaling that facilitate macrophage reprogramming, including paracrine signaling and activation of innate immune checkpoints. We also describe intervention strategies targeting macrophage plasticity to limit disease progression and address their implications in cancer chemo- and immunotherapy.

Trial watch: FDA-approved Toll-like receptor agonists for cancer therapy

Toll-like receptors (TLRs) have first been characterized for their capacity to detect conserved microbial components like lipopolysaccharide (LPS) and double-stranded RNA, resulting in the elicitation of potent (innate) immune responses against invading pathogens. More recently, TLRs have also been shown to promote the activation of the cognate immune system against cancer cells. Today, only three TLR agonists are approved by FDA for use in humans: the bacillus Calmette-Guérin (BCG), monophosphoryl lipid A (MPL) and imiquimod. BCG (an attenuated strain of Mycobacterium bovis) is mainly used as a vaccine against tuberculosis, but also for the immunotherapy of in situ bladder carcinoma. MPL (derived from the LPS of Salmonella minnesota) is included in the formulation of Cervarix®, a vaccine against human papillomavirus-16 and -18. Imiquimod (a synthetic imidazoquinoline) is routinely employed for actinic keratosis, superficial basal cell carcinoma, and external genital warts (condylomata acuminata). In this Trial Watch, we will summarize the results of recently completed clinical trials and discuss the progress of ongoing studies that have evaluated/are evaluating FDA-approved TLR agonists as off-label medications for cancer therapy.

Macrophage reprogramming for therapy

Dysfunction of the immune system underlies a plethora of human diseases, requiring the development of immunomodulatory therapeutic intervention. To date, most strategies employed have been focusing on the modification of T lymphocytes, and although remarkable improvement has been obtained, results often fall short of the intended outcome. Recent cutting-edge technologies have highlighted macrophages as potential targets for disease control. Macrophages play central roles in development, homeostasis and host defence, and their dysfunction and dysregulation have been implicated in the onset and pathogenesis of multiple disorders including cancer, neurodegeneration, autoimmunity and metabolic diseases. Recent advancements have led to a greater understanding of macrophage origin, diversity and function, in both health and disease. Over the last few years, a variety of strategies targeting macrophages have been developed and these open new therapeutic opportunities. Here, we review the progress in macrophage reprogramming in various disorders and discuss the potential implications and challenges for macrophage-targeted approaches in human disease.

Topical therapies for the treatment of cervical intraepithelial neoplasia (CIN) 2-3: A narrative review

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CIN management is currently surveillance or surgical therapy. This review describes current research on medical therapies.

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Imiquimod is the most studied with evidence of safety and efficacy.

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5-Fluorouracil has also shown promise with two clinical trials showing efficacy as adjuvant and primary treatment.

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Antivirals therapies have produced mixed results with cidofovir showing the most potential.

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The data remains weak regarding hormonal, herbal and alternative therapies rending it difficult to draw conclusions.

Current management of Cervical Intraepithelial Neoplasia (CIN), caused by high-risk human papillomavirus (hr-HPV), is based on surveillance and surgical therapy. Procedures carry potential risks such as preterm birth, and access remains limited throughout the world. However, there are no medical therapies recommended to promote the clearance of hr-HPV infection or CIN. Ultimately, even if less efficacious than excision procedures, medical therapies have the potential to decrease cervical cancer by eliminating barriers to treatment, such as access to treatment, or serving as an adjunct to surgical treatment in both high- and low-resource settings.

This review describes current research on topical therapies with the potential for self-application for the treatment of HPV or CIN. Therapies included are immune-modulators, anti-proliferative medications, antivirals, hormones, and herbal/alternative therapies. Randomized trials of immune-modulating (imiquimod), anti-proliferative (5-fluorouracil), and anti-viral (cidofovir) therapies have had the most promising results. However, no option has sufficient clinical trial evidence to be recommended as treatment for CIN 2–3 and surgery remains the standard of care.

The research described in this review serves as a guide for the development of future trials in the burgeoning arena of topical therapies for CIN 2–3.

Methodological refinement of Aldara-induced psoriasiform dermatitis model in mice

Imiquimod (IMQ)-induced skin inflammation is currently the most widely accepted psoriasis animal model, however, it features several limitations. We have modified the IMQ-model to minimize its systemic effects towards effectively maintaining the characteristic skin reactions. The original protocol (OP) uses 62.5 mg Aldara cream (or vaseline) on the shaved back skin of mice for 4 days. In contrast, in our modified protocol (MP) 25 mg Aldara and vaseline are applied simultaneously in separate Finn chambers over the dorsal skin of mice. In both the OP and MP groups, histology showed unequivocal hallmarks of psoriasiform dermatitis. Additionally, skin scaling and blood perfusion values were similar. While Aldara elicited significantly increased skin thickness in the MP group, significant weight loss, spleen enlargement, increased inflammatory cytokine levels in plasma, and treatment related death were only observed in the OP group. Our new method reproduces psoriatic skin alterations highlighting considerably reduced systemic inflammatory reactions. Possessing psoriasiform and control skin areas on the same mouse also reduces inter-individual differences. Additionally, the new method permits prolonged IMQ treatment studies to mimic the chronic nature of psoriasis. Finally, our experimental approach may also be used in other mouse models, to prevent the undesired systemic effects of topically applied drugs.

Systemic adverse events in imiquimod use for cervical intraepithelial neoplasia - A case series

Treatment for cervical intraepithelial neoplasia (CIN) often consists of an excisional procedure. However, less invasive treatment methods have been explored, such as topical treatment with imiquimod cream. Imiquimod has been proven to be effective in the regression of vulvar intraepithelial neoplasia (VIN) and vaginal intraepithelial neoplasia (VAIN). Previous studies have investigated the effect of imiquimod in CIN and showed well tolerated adverse effects. During a current study in the Netherlands, a number of adverse events have occurred. This case series presents a selection of these. Gynaecologists should be aware of the possible adverse effects of topical treatment with imiquimod cream.

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Cervical intraepithelial neoplasia (CIN) is usually treated with an excisional procedure.

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A less invasive treatment method has been investigated: imiquimod cream.

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During a study in the Netherlands, a number of adverse events have occurred.

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Adverse effects were presented in this case series.

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Gynaecologists should be aware of the possible adverse effects.

Effect of paiteling on the alteration of persistent HR-HPV infection after panhysterectomy

This study aims to determine the effect of paiteling by placing a vaginal stump on the outcome of persistent high-risk human papillomavirus (HR-HPV) infection after hysterectomy for cervical intraepithelial neoplasia (CIN). From January 2013 to December 2015, 125 patients were enrolled in the study. These patients were divided into groups, according to patient’s preference. There were 55 patients in the paiteling group, while there were 70 patients in the control group. At the end of the third and ninth month, Thinprep cytology test (TCT) and human papillomavirus (HPV) typing were reviewed to determine the changes in HR-HPV and its complications. The negative conversion rates of these two groups were observed. Patients in the control group were observed and followed up without treatment. At the third month after treatment, HPV negative rates were 83.64% and 34.29% in the paiteling group and control group, respectively (χ2 = 30.444, P < 0.01). In the ninth month, the rate of HPV negative conversion was 90.91% in the paiteling group and 48.57% in the control group (χ2 = 25.047, P < 0.01). The difference between the two groups was statistically significant, and patients in both groups had no obvious adverse reactions. Paiteling irrigation at the vaginal stump can accelerate the positive-to-negative conversion of HR-HPV infection after panhysterectomy.

Targeting GLI Transcription Factors in Cancer

Aberrant activation of hedgehog (Hh) signaling has been observed in a wide variety of tumors and accounts for more than 25% of human cancer deaths. Inhibitors targeting the Hh signal transducer Smoothened (SMO) are widely used and display a good initial efficacy in patients suffering from basal cell carcinoma (BCC); however, a large number of patients relapse. Though SMO mutations may explain acquired therapy resistance, a growing body of evidence suggests that the non-canonical, SMO-independent activation of the Hh pathway in BCC patients can also account for this adverse effect. In this review, we highlight the importance of glioma-associated oncogene (GLI) transcription factors (the main downstream effectors of the canonical and the non-canonical Hh cascade) and their putative role in the regulation of multiple oncogenic signaling pathways. Moreover, we discuss the contribution of the Hh signaling to malignant transformation and propose GLIs as central hubs in tumor signaling networks and thus attractive molecular targets in anti-cancer therapies.

Development of podophyllotoxin‑loaded nanostructured lipid carriers for the treatment of condyloma acuminatum

Condyloma acuminatum (CA) is a common sexually transmitted disease caused by human papillomavirus (HPV). Podophyllotoxin (POD), a cytotoxic compound, is able to effectively treat HPV; however, the severe irritation side effects of POD restrict its use as a treatment for CA. The aim of the present study was to construct novel POD‑loaded nanostructured nanolipid carriers (POD‑NLCs) and evaluate their physicochemical characteristics and cytotoxicity. POD‑NLCs (0.5%) were prepared using emulsion‑evaporation and low temperature‑solidification methods with optimized conditions and preparations. Subsequently, the POD‑NLCs were physicochemically characterized and their in vitro and in vivo release efficiencies and in vitro cytotoxicity were studied. The prepared POD‑NLCs had an average particle size, ζ potential, polydispersity index and encapsulation efficacy of 178.5±20 nm, ‑27±0.5 mV, 0.18±0.01 and 82.9±2%, respectively. In vitro and in vivo release studies demonstrated that POD‑NLCs are able to provide sustained drug delivery for 72 h in vitro and 10 h in the mucosa. Compared with a tincture formulation of POD (POD‑T), POD‑NLC induced less inflammatory cytokine production in the cervical mucous and led to a decreased histopathological score. In addition, a cytotoxicity assay demonstrated that inhibition of the POD‑NLCs was 98.4% at 24 h and remained >98% up to 72 h. Furthermore, more cells were arrested in the G2/M phase of the cell cycle following POD‑NLC treatment compared with the POD‑T treatment. The present study provides evidence that POD‑NLC is a promising delivery system for the treatment of CA.

Basic understanding and therapeutic approaches to target toll-like receptors in cancerous microenvironment and metastasis

Toll-like receptors (TLRs) are transmembrane components that sense danger signals, like damage- and pathogen-associated molecular pattern molecules, as receptors, and maintain homeostasis in tissues. They are mainly involved in immune system activation through a variety of mediators, which either carry out (1) elimination of pathogenic threats and redressing homeostatic imbalances or (2) contribution to the initiation and worsening of pathological conditions, including cancers. Under physiological conditions, TLRs coordinate the innate and adaptive immunity, and inhibit autoimmune disorders. In pathological conditions, such as cancer, they can present both tumor and receptor-specific roles. Although the roles of individual TLRs in various cancers have been described, the effects of targeting TLRs to treat cancer and prevent metastasis are still controversial. A growing body of literature has suggested contribution of both activators and inhibitors of TLR signaling pathway for cancer treatment, dependent on several context-specific factors. In short, TLRs can play dual roles with contradictory outcomes in neoplastic conditions. This hampers the development of TLR-based therapeutic interventions. A better understanding of the interwoven TLR pathways in cancerous microenvironment is necessary to design TLR-based therapies. In this review, we consider the molecular mechanisms of TLRs signaling and their involvement in tumor progression. Therapeutic modalities targeting TLRs for cancer treatment are discussed as well.

STING expression and response to treatment with STING ligands in premalignant and malignant disease

Human papilloma virus positive (HPV⁺) tumors represent a large proportion of anal, vulvar, vaginal, cervical and head and neck squamous carcinomas (HNSCC) and late stage invasive disease is thought to originate from a premalignant state. Cyclic dinucleotides that activate STimulator of INterferon Genes (STING) have been shown to cause rapid regression of a range of advanced tumors. We aimed to investigate STING ligands as a novel treatment for papilloma. We tested therapies in a spontaneous mouse model of papilloma of the face and anogenital region that histologically resembles human HPV-associated papilloma. We demonstrate that STING ligands cause rapid regression of papilloma, associated with T cell infiltration, and are significantly more effective than Imiquimod, a current immunotherapy for papilloma. In humans, we show that STING is expressed in the basal layer of normal skin and lost during keratinocyte differentiation. We found STING was expressed in all HPV-associated cervical and anal dysplasia and was strongly expressed in the cancer cells of HPV⁺ HNSCC but not in HPV-unrelated HNSCC. We found no strong association between STING expression and progressive disease in non-HPV oral dysplasia and oral pre-malignancies that are not HPV-related. These data demonstrate that STING is expressed in basal cells of the skin and is retained in HPV⁺ pre-malignancies and advanced cancers, but not in HPV-unrelated HNSCC. However, using a murine HNSCC model that does not express STING, we demonstrate that STING ligands are an effective therapy regardless of expression of STING by the cancer cells.

Optimization of a Vaginal Suppository Formulation to Deliver SHetA2 as a Novel Treatment for Cervical Dysplasia

Cervical dysplasia induced by the human papilloma virus unpredictably progresses to cervical cancer. Therapeutic options are invasive and affect the patient's quality of life. SHetA2 has demonstrated therapeutic efficacy against human and murine human papilloma virus-induced tumors, but its oral bioavailability is <1%. An optimized vaginal suppository formulation can deliver SHetA2 in sufficient doses to prevent cervical dysplasia. The quality by design approach was employed to optimize the suppository formulation consisting of cocoa butter as base with 5% Kolliphor and 40% SHetA2. The suppository had a content uniformity of 105.44 ± 0.42%, melted in <8 min, and had a complete release of SHetA2 in water. Administration of the suppository to mice-achieved cervix concentrations that were significantly higher than the SHetA2 therapeutic concentration, with the maximum concentration (C_max-cervix = 336.78 μg/g) being more than 100-fold the therapeutic SHetA2 concentration. Furthermore, the levels of cyclin D1 protein decreased 9-fold indicating a correlation of drug concentrations with the pharmacodynamic endpoint. These proof-of-concept studies suggest that the SHetA2 optimized vaginal suppository formulation may have a potential use in the prevention of cervical dysplasia, but detailed efficacy studies are required to confirm this assumption.

Treatment of Cervical Intraepithelial Neoplasia: Patients Preferences for Surgery or Immunotherapy with Imiquimod

Imiquimod has been studied as a noninvasive pharmacological treatment alternative to large loop excision of the transformation zone (LLETZ) for high-grade cervical intraepithelial neoplasia (CIN), to prevent long-term obstetric complications from surgical treatment. This study aims to investigate womens' preferences for treatment of high-grade CIN with imiquimod or LLETZ. A labeled discrete choice experiment was conducted among 100 women with abnormal cervical cytology in 5 hospitals in the Netherlands between March 2014 and December 2015. Participants were asked to choose between imiquimod treatment or standard surgical treatment in 9 separate scenarios, based on the following treatment characteristics: treatment success rate, rate of side effects, risk of premature birth in subsequent pregnancies, and risk of subfertility after treatment. The levels of these characteristics differed for the imiquimod alternatives. Women assigned a positive utility to LLETZ compared with imiquimod. When making a choice for imiquimod, women preferred a higher treatment success rate and a lower risk of premature birth, infertility and side effects. The choice for imiquimod treatment was also influenced by the intention of a future pregnancy. Subgroup analyses revealed that a lower efficacy regarding imiquimod might be more acceptable for women who desired a future pregnancy compared with women who did not desire a future pregnancy. Women with a future pregnancy wish may prefer treatment of high-grade CIN with imiquimod cream over LLETZ, if the risk of subfertility and premature birth is low.

Moving forward with human papillomavirus immunotherapies

Persistent human papillomavirus (HPV) is the primary etiologic agent of cervical cancer and causes a significant number of vulvar, penile, anal and oropharyngeal cancers. The development of highly effective HPV therapeutic vaccines is a reasonable goal given the recent advances in basic and applied immunology. A number of vaccine strategies designed to induce systemic T cell responses have been tested in clinical trials against high grade cervical or vulvar high grade neoplasia and cancers, but with limited success. In line with the emerging trend to focus more on the epithelial context of HPV infection and premalignant disease, it might be advantageous to develop vaccination strategies that promote trafficking of HPV-specific T cells into lesions and overcome the local immunosuppressive environment. The development of more biologically relevant animal models would improve the preclinical evaluation of therapeutic vaccine candidates. Finally, persistent infection and low grade lesions may prove to be easier targets for therapeutic vaccines, and these vaccines would likely be commercially viable in high income countries and valuable components in screen and treat programs in low resource settings.

TOPical Imiquimod treatment of high-grade Cervical intraepithelial neoplasia (TOPIC trial): study protocol for a randomized controlled trial

Background

Cervical intraepithelial neoplasia (CIN) is the premalignant condition of cervical cancer. Whereas not all high grade CIN lesions progress to cervical cancer, the natural history and risk of progression of individual lesions remain unpredictable. Therefore, high-grade CIN is currently treated by surgical excision: large loop excision of the transformation zone (LLETZ). This procedure has potential complications, such as acute haemorrhage, prolonged bleeding, infection and preterm birth in subsequent pregnancies. These complications could be prevented by development of a non-invasive treatment modality, such as topical imiquimod treatment.

The primary study objective is to investigate the efficacy of topical imiquimod 5 % cream for the treatment of high-grade CIN and to develop a biomarker profile to predict clinical response to imiquimod treatment. Secondary study objectives are to assess treatment side-effects, disease recurrence and quality of life during and after different treatment modalities.

Methods/design

The study design is a randomized controlled trial. One hundred forty women with a histological diagnosis of high-grade CIN (CIN 2–3) will be randomized into two arms: imiquimod treatment during 16 weeks (experimental arm) or immediate LLETZ (standard care arm). Treatment efficacy will be evaluated by colposcopy with diagnostic biopsies at 20 weeks for the experimental arm. Successful imiquimod treatment is defined as regression to CIN 1 or less, successful LLETZ treatment is defined as PAP 1 after 6 months. Disease recurrence will be evaluated by cytology at 6, 12 and 24 months after treatment. Side-effects will be evaluated using a standardized report form. Quality of life will be evaluated using validated questionnaires at baseline, 20 weeks and 1 year after treatment. Biomarkers, reflecting both host and viral factors in the pathophysiology of CIN, will be tested at baseline with the aim of developing a predictive biomarker profile for the clinical response to imiquimod treatment.

Discussion

Treatment of high-grade CIN lesions with imiquimod in a selected patient population may diminish complications as a result of surgical intervention. More knowledge on treatment efficacy, side effects and long-term recurrence rates after treatment is necessary.

Trial registration

EU Clinical Trials Register EU-CTR2013-001260-34. Registered 18 March 2013.

Medical Ethical Committee approval number: NL44336.068.13 (Medical Ethical Committee Maastricht University Hospital, University of Maastricht).

Affiliation: Maastricht University Hospital.

Registration number ClinicalTrials.gov: NCT02329171.

Clinical applicability of immunotherapy of cervical intraepithelial neoplasia

Immunotherapy for cervical intraepithelial neoplasia (CIN) has not yet reached clinical applicability, but seems sensible and shows promising preliminary results. One of the most promising forms of immunotherapy for CIN may currently be imiquimod, because of its established role in other human papillomavirus (HPV)-induced genital conditions, its promising treatment efficacy in high-grade CIN, and its off-label availability. Although imiquimod cannot yet replace the current gold standard treatment for CIN [i.e., large loop excision of the transformation zone (LLETZ)] in all patients, it may be considered in subgroups of patients; for example, young women who may wish to become pregnant in the future, or patients with recurrent CIN lesions in whom a second LLETZ is to be avoided. Immunotherapy of CIN could be extended to post-treatment vaccination, in order to prevent new HPV infections and disease recurrence.

An overview of early investigational drugs for the treatment of human papilloma virus infection and associated dysplasia

INTRODUCTION

High-risk HPV (HR-HPV) related invasive cervical cancer (ICC) causes >270,000 deaths per annum world-wide with over 85% of these occurring in low-resource countries. Ablative and excisional treatment modalities are restricted for use with high-grade pre-cancerous cervical disease with HPV infection and low-grade dysplasia mostly managed by a watch-and-wait policy.

AREAS COVERED

Various pharmacological approaches have been investigated as non-destructive alternatives for the treatment of HR-HPV infection and associated dysplasia. These are discussed dealing with efficacy, ease-of-use (physician or self-applied), systemic or locally applied, side-effects, cost and risks. The main focus is the perceived impact on current clinical practice of a self-applied, effective and safe pharmacological anti-HPV treatment.

EXPERT OPINION

Current prophylactic HPV vaccines are expensive, HPV type restricted and have little effect in already infected women. Therapeutic vaccines are under development but are also HPV type-restricted. At present, the developed nations use national cytology screening and surgical procedures to treat only women identified with HPV-related high-grade dysplastic disease. However, since HPV testing is rapidly replacing cytology as the test-of-choice, a suitable topically-applied and low-cost antiviral treatment could be an ideal solution for treatment of HPV infection per se with test-of-cure carried out by repeat HPV testing. Cytology would only then be necessary for women who remained HPV positive. Although of significant benefit in the developed countries, combining such a treatment with self-sampled HPV testing could revolutionise the management of this disease in the developing world which lack both the infrastructure and resources to establish national cytology screening programs.

Imiquimod in cervical, vaginal and vulvar intraepithelial neoplasia: a review

Human papillomavirus (HPV) infection is in the vast majority of patients accountable for the development of vulvar, cervical and vaginal intraepithelial neoplasia (VIN, CIN, VAIN); precursors of vulvar, cervical and vaginal cancers. The currently preferred treatment modality for high grade VIN, CIN and VAIN is surgical excision. Nevertheless surgical treatment is associated with adverse pregnancy outcomes and recurrence is not uncommon. The aim of this review is to present evidence on the efficacy, safety and tolerability of imiquimod (an immune response modifier) in HPV-related VIN, CIN and VAIN. A search for papers on the use of imiquimod in VIN, CIN and VAIN was performed in the MEDLINE, EMBASE and Cochrane library databases. Data was extracted and reviewed. Twenty-one articles met the inclusion criteria and were analyzed; 16 on VIN, 3 on CIN and 2 on VAIN. Complete response rates in VIN ranged from 5 to 88%. Although minor adverse effects were frequently reported, treatment with imiquimod was well tolerated in most patients. Studies on imiquimod treatment of CIN and VAIN are limited and lack uniformly defined endpoints. The available evidence however, shows encouraging effect. Complete response rates for CIN 2-3 and VAIN 1-3 ranged from 67 to 75% and 57 to 86% respectively. More randomized controlled trials on the use of imiquimod in CIN, VAIN and VIN with extended follow-up are necessary to determine the attributive therapeutic value in these patients.

Immunoprevention of human papillomavirus-associated malignancies

Persistent infection by one of 15 high-risk human papillomavirus (hrHPV) types is a necessary but not sufficient cause of 5% of all human cancers. This provides a remarkable opportunity for cancer prevention via immunization. Since Harald zur Hausen's pioneering identification of hrHPV types 16 and 18, found in approximately 50% and 20% of cervical cancers, respectively, two prophylactic HPV vaccines containing virus-like particles (VLP) of each genotype have been widely licensed. These vaccines are beginning to affect infection and HPV-associated neoplasia rates after immunization campaigns in adolescents. Here, we review recent progress and opportunities to better prevent HPV-associated cancers, including broadening immune protection to cover all hrHPV types, reducing the cost of HPV vaccines especially for developing countries that have the highest rates of cervical cancer, and immune-based treatment of established HPV infections. Screening based upon George Papanicolaou's cervical cytology testing, and more recently detection of hrHPV DNA/RNA, followed by ablative treatment of high-grade cervical intraepithelial neoplasia (CIN2/3) have substantially reduced cervical cancer rates, and we examine their interplay with immune-based modalities for the prevention and eventual elimination of cervical cancer and other HPV-related malignancies.

Topical hexaminolevulinate photodynamic therapy for the treatment of persistent human papilloma virus infections and cervical intraepithelial neoplasia

INTRODUCTION

Current treatments for high-grade cervical intraepithelial neoplasia (CIN2/3) are mainly excisional procedures, which are associated with significant side effects and pose risks for future pregnancies. An effective and safe therapy is needed to reduce the requirement for surgical interventions in women of reproductive age.

AREAS COVERED

This review looks at the pharmacokinetic and clinical data for topical hexaminolevulinate (HAL) photodynamic therapy (PDT), which is currently entering late phase clinical trials for high-grade CIN. The authors include published studies in patients and volunteers but laboratory and animal studies have been excluded as have studies on other porphyrins such as Photofrin, 5-aminolevulinic acid, methyl aminolevulinate and studies reporting other clinical applications for HAL.

EXPERT OPINION

Topical HAL PDT has potential as a non-surgical tissue-preserving treatment for CIN and persistent oncogenic human papilloma virus infections. HAL PDT selectively treats the entire epithelial sheet, without the tissue destruction seen in excisional procedures. The authors believe that this treatment could replace surgery in a large proportion of patients. It would be of particular value to the high percentage of women who are interested in future child-bearing. If the treatment is approved, it is very likely that physicians will want to use this treatment, as many patients will be keen to consider a non-surgical option.

Ménage à trois: an evolutionary interplay between human papillomavirus, a tumor, and a woman

Cervical cancer is the third most common cancer in women with human papillomavirus (HPV) being a key etiologic factor of this devastating disease. In this article, we describe modern advances in the genomics and transcriptomics of cervical cancer that led to uncovering the key gene drivers. We also introduce, herein, a model of cervical carcinogenesis that explains how the interplay between virus, tumor, and woman results in the selection of clones that simultaneously harbor genomic amplifications for genes that drive cell cycle, antiviral response, and inhibit cell differentiation. The new model may help researchers understand the controversies in antiviral therapy and immunogenetics of this cancer and may provide a basis for future research directions in early diagnostics and personalization of therapy.