Cidofovir: to use or not to use?

Infantile recurrent respiratory papillomatosis: review of adjuvant therapies

BACKGROUND

Recurrent respiratory papillomatosis is a potentially life-threatening condition characterised by the growth of exophytic lesions within the larynx and trachea. The principal aim of management is maintenance of an adequate airway by surgical debulking. Several adjuvant therapies have been used to varying effect to reduce the burden of this disease and increase the interval between debulking procedures. The most severe cases present in children aged under three years, who are therefore most likely to need adjuvant therapies. The current evidence base on adjuvant treatments relating to children who present aged under three years has been reviewed.

METHODS

A literature review of articles in Cochrane, PubMed and Embase databases was carried out. Given the rarity of the condition in this age group, all the literature relates to case reports and case series.

RESULTS AND CONCLUSION

The following adjuvant therapies have been used in children who presented under three years of age: quadrivalent human papilloma virus vaccine, intralesional cidofovir, pegylated interferon, alpha-interferon, cimetidine and cetuximab.

Identification of potential antivirals against SARS-CoV-2 using virtual screening method

SARS-CoV-2 has triggered a major epidemic among people around the world, and it is the newest in the sequence to become prevalent among other infectious diseases. The drug repurposing concept has been utilized effectively for numerous viral infections. Considering the situation and the urgency, the idea of drug repurposing for coronavirus infection (COVID-19) is also being studied. The molecular docking method was used for the screening of 29 antiviral drugs against primary protease proteins (MPP) of SARS-CoV-2, spike ecto-domain, spike receptor binding domain, Nsp9 RNA binding protein, and HR2 domain. Among these drugs, in terms of least binding energy, Indinavir, Sorivudine, Cidofovir, and Darunavir showed minimum docking scores with all the key proteins. For ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) analysis, the ADMET properties of the top 4 drug candidates were retrieved through literature study. This analysis revealed that these drug candidates are well metabolized, distributed, and bioavailable, but have some undesirable effects. Furthermore, some approved structural analogues, such as Telbivudine, Tenofovir, Amprenavir, Fosamprenavir, etc., were predicted as similar drugs which may also be used for treating viral infections. We highly recommend these drug candidates as potential fighters against the deadly SARS-CoV-2 virus, and suggest in vivo trials for experimental validation of our findings.

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.

Recurrent respiratory papillomatosis of the airway: The experience of an endoscopic unit

INTRODUCTION

Recurrent respiratory papillomatosis (RPP) is a rare benign neoplasm caused by human papillomavirus (HPV). RPP is characterized by recurrent proliferation of the papillomata in the respiratory tract.

OBJECTIVES AND METHODS

Retrospective analysis of all adult patients with diagnosis of recurrent respiratory papillomatosis admitted to our endoscopic unit between 2000 and 2013 with histological proved papillomatosis.

RESULTS

Four patients were included (3 women) with an average age of 53±19 years (27-72). Before endoscopy unit admission, all the patients have been previously submitted to surgical removal of the papillomas with a median number of surgeries per patient of 6.5. These patients were submitted to therapeutic endoscopy and the most frequent endoscopic treatments were Laser YAG and local injection of cidofovir. All the patients treated with cidofovir presented complete remission of the disease. The median follow-up was 6 years: 2 presented malignant transformation to epidermoid carcinoma and 1 had severe dysplasia on the histological examination. We describe the four cases due to different forms of presentation.

CONCLUSION

Papillomatosis of the airway is a rare condition predisposing to malignant transformation. RRP tends to recur and repeated surgeries are needed to remove papillomatas. Endoscopic treatment is important for the removal of the papillomas that are not accessible via laryngoscopy (YAG Laser, cryotherapy, etc.) and for resistant moderate/severe cases of RPP because it allows intralesional administration of adjuvant therapy like cidofovir.

Clinical efficiency of quadrivalent HPV (types 6/11/16/18) vaccine in patients with recurrent respiratory papillomatosis

The aim of the study was to assess the clinical efficiency of quadrivalent HPV (types 6/11/16/18) vaccine in patients with recurrent respiratory papillomatosis (RRP). This was a prospective study of patients with RRP treated from January 2009 to July 2012 at the Ear, Nose and Throat Department of the Emergency County Hospital of Cluj-Napoca, Romania. Demographic characteristics, onset of RRP, HPV typing, use and number of cidofovir injections, number of surgeries for RRP per year, and use of human papillomavirus vaccine (types 6, 11, 16, 18) (recombinant, adsorbed)/Silgard® were considered from all the patients included in the study. Charts were reviewed for follow-up after diagnosis, after cidofovir, and after Silgard; all the statistical tests were applied at a significance level of 5%. The recurrences were observed within 27.53 ± 11.24 days after intralesional cidofovir injection. Thirteen patients with recurrence after cidofovir agreed and received Silgard® vaccine. 85% [54.44–99.41] of patients had no recurrences during 1-year follow-up. The recurrence of papillomas was observed in two patients (15%, 95% CI [0.59–45.56]), one with adult-onset RRP and one with juvenile-onset RRP. Both recurrences appeared after the first Silgard dose; one month after the third vaccine dose each patient underwent a new surgery for remaining papillomas with no recurrences at 1-year follow-up visit. Silgard® vaccination had a good effect and proved to be efficient in the treatment of our patients with RRR without appearance of recurrence in 85% of the patients during 1-year follow-up.

Treatment of paediatric laryngeal papillomas: web survey of British Association of Paediatric Otolaryngologists

Background and objective:

Recurrent respiratory papillomatosis is the most common benign neoplasm of the larynx in children. Intralesional injection of cidofovir may have some potential as an adjunctive treatment. There is no standardised protocol in the UK for the management of recurrent respiratory papillomatosis. This study aimed to investigate the management practices of surgeons treating paediatric recurrent respiratory papillomatosis in the UK.

Method:

A web questionnaire survey was sent by e-mail to all members of the British Association of Paediatric Otorhinolaryngology.

Results:

Out of 35 respondents, 23 were at that time treating children with recurrent respiratory papillomatosis. Nineteen respondents preferred to use a microdebrider, 12 preferred laser, and 5 preferred cold steel along with either laser or a microdebrider. Twelve surgeons used cidofovir for selected patients and 12 surgeons did not use cidofovir for any patients. Cidofovir was considered after 0–4 surgical procedures by seven respondents, after 4–6 surgical procedures by four respondents and after 6 surgical procedures by six respondents. Eleven respondents warned patients about the possible side effects of cidofovir and five gave no warning.

Conclusion:

There was no consensus as to when it would be appropriate to use cidofovir, indicating the need for cidofovir usage guidelines.

Adult recurrent respirator papillomatosis: a new therapeutic approach with pegylated interferon alpha 2a (Peg-IFNα-2a) and GM-CSF

OBJECTIVE

To determine a new therapeutic approach using granulocyte monocyte-colony-stimulating factor (GM-CSF) and pegylated interferon alpha 2a (Peg-IFNα-2a) as adjuvant therapy in patients with adult recurrent respiratory papillomatosis.

STUDY DESIGN

Descriptive observational clinical trial.

SETTING

Departments of Otolaryngology and Immunology.

METHODS

Fourteen patients with adult recurrent respiratory papillomatosis were examined regarding medical history and number of operations before and after treatment. Voice disorder and glottal stop were evaluated using the Voice-Related Quality-of-Life instrument. Papilloma staging was determined using the Coltera/Derkay diagram. The patients received Peg-IFNα-2a at 180 mcg weekly for 6 months. In the third month, the patients began GM-CSF treatment at 400 mcg weekly for 2 months. The patients were observed for 12 months after treatment ended.

RESULTS

Eleven patients met the study criteria; 3 patients had tracheotomies before treatment, and they were decannulated after treatment. Before treatment, the scale of voice quality ranged from 34 to 45 points (mean, 38.31). After treatment, the range was 12 to 35 points (mean, 21.09; P < .001). Prior to therapy, the glottal stop ranged from 50% to 90% (average, 62.27%). After therapy, the range decreased to 0% to 15% (mean, 4.63%; P < .001). The number of surgical interventions decreased. Two patients each had 1 surgical intervention after treatment began.

CONCLUSION

A new adjuvant treatment based on immunogenetic mechanisms against human laryngeal papilloma virus, with expectations of reducing disease aggressiveness and the number of operations, avoids the risks of surgery.

IMPLICATION FOR PRACTICE

Peg-IFNα-2a and GM-CSF is an adjuvant therapy for treating adult recurrent respiratory papillomatosis.

The impact of cidofovir treatment on viral loads in adult recurrent respiratory papillomatosis

Cidofovir is an antiviral agent used in the therapy of recurrent respiratory papillomatosis (RRP). In this study, we hypothesized that cidofovir is effective in decreasing the viral load of human papillomavirus (HPV). We established a type specific real-time PCR and measured HPV DNA loads. The course of viral load of HPV types 6 and 11 after repeated applications of cidofovir intralesionally was compared to the clinical outcome using a modified Derkay score. In 6 of the 8 (75 %) patients, we detected HPV 6. In 2 (25 %) patients, we detected HPV 11. In all of the patients, the viral load and the modified Derkay score decreased significantly during the treatment. We conclude that viral load of HPV can be monitored using the technique described here. Cidofovir in combination with surgical debulking reduces the viral load in patients with RRP. Relapses of the symptoms cannot be avoided but might be delayed.

Effectiveness of cidofovir intralesional treatment in recurrent respiratory papillomatosis

To present the results of recurrent respiratory papillomatosis (RRP) treatment with surgical excision and adjuvant anti-viral cidofovir intralesional use and to examine the correlation between the cidofovir effectiveness and the patient previous history of multiple larynx procedures, age, extension of lesion and dose. 32 patients with laryngeal papillomas were treated with cidofovir in our Department between I.2009 and I.2011. The number of previous RRP debulking procedures ranged from 1 to 100. The intensity of papillomatosis differed from one anatomic site and moderate growth to four or five localizations with heavy extension. The number of injections per patient varied from 1 to 7, and the total volume of 5 mg/ml solution varied from 2 to 33 ml. The injections were combined with laser debulking of the lesions. In disperse papillomata, the injections were administered in particular anatomical sites in 4–6 weeks intervals, in massive lesions injections were repeated in the same anatomical site in 2–4 weeks. Complete remission was observed in 18 out of 32 patients. 13 patients showed remission in a place of cidofovir injection. One patient did not react to the drug. In four patients, new changes in injection places appeared. In two patients, hepatic toxic side effects were observed. Intralesional cidofovir injection has been shown to be an effective and safe therapy for laryngeal papillomatosis and should be considered in those patients who experienced disease relapse.

Mucosal Bridge and Pitting of the True Vocal Fold: An Unusual Complication of Cidofovir Injection

We describe a unique complication of intralaryngeal cidofovir injection and present the case of a patient with recurrent respiratory papillomatosis in whom both a mucosal bridge and a pit of the true vocal fold developed after intralaryngeal cidofovir injection. A 40-year-old man presented with laryngeal papillomatosis 19 years after being treated with surgery and adjuvant radiotherapy for leiomyosarcoma of the cervical esophagus. The patient underwent 5 papillomatosis excisions combined with subepithelial injections of cidofovir to the bilateral true vocal folds at a concentration of 5 mg/mL without any complications. He subsequently received 2 higher-dose cidofovir treatments 6 weeks apart because of a poor response to the previous treatments. Two months later, there was evidence of a large mucosal bridge along the free edge of the right vocal fold and a deep pit in the lateral aspect of the same vocal fold. We conclude that repeated high-dose intralesional injection of cidofovir may result in significant morphological changes to the vocal fold, most likely due to mucosal injury.

Pharmacotherapy of recurrent respiratory papillomatosis: an expert opinion

BACKGROUND

Recurrent respiratory papillomatosis is caused by the human papillomavirus types (HPV) 6 and 11. It affects both children and adults. In a small number of cases, the disease can be very aggressive causing significant morbidity and possibly death. Surgical therapy is the primary treatment but in patients with aggressive disease, adjunctive therapy is initiated. The majority of these adjuncts center on immunomodulation, disruption of molecular signaling cascades or interruption of viral replication to help decrease the severity of the disease. Recently, a preventative vaccine has become available but data on its effectiveness will be at least a decade away. In the mean time, researchers are examining other vaccination strategies in the fight against HPV disease.

OBJECTIVE

We will review the following pharmacotherapies used in the adjunct treatment of RRP: interferon, acyclovir, ribivirin, cidofovir, COX-2 inhibitors, retinoids, anti-reflux medications, zinc, indole-3-carbinol, therapeutic/preventative vaccines.

METHODS

This is a review paper. Utilizing Medline and Pubmed from 1966 to present, the key words as well as the above listed adjunct treatments were searched for relevant papers.

CONCLUSION

The evidence supporting each of these adjuncts varies with a majority having only case reports or cases-series to support their use. However, there is hope on the horizon with regard to the HPV vaccine and its potential to prevent future transmission of this disease.