Pilot trial of ribavirin for the treatment of laryngeal papillomatosis

Pharmacodynamic and therapeutic pilot studies of single-agent ribavirin in patients with human papillomavirus-related malignancies

OBJECTIVES

Ribavirin inhibits eukaryotic translation initiation factor 4E (eIF4E), thereby decreasing cap-dependent translation. In this two-part study, we assessed the pharmacodynamic effects and therapeutic potential of ribavirin in human papillomavirus (HPV)-related malignancies.

METHODS

In the pharmacodynamic study, ribavirin (400 mg BID for 14 days) was evaluated in 8 patients with HPV-positive localized oropharyngeal carcinoma with phosphorylated-eIF4E (p-eIF4E) ≥ 30%. In the therapeutic study, ribavirin (1400 mg BID in 28-day cycles, continuously dosed) was evaluated in 12 patients with recurrent and/or metastatic HPV-related cancer. Dose interruptions or reductions were allowed according to prespecified criteria. Toxicities were assessed in accordance with National Cancer Institute Common Terminology Criteria for Adverse Events version 4; response was assessed using Response Evaluation Criteria in Solid Tumors version 1.1. Patients remained on study until disease progression or unacceptable toxicity.

RESULTS

Six patients were evaluable in the pharmacodynamic study: 4 had decreased p-eIF4E after 14 days of ribavirin. In the therapeutic study, 12 patients were evaluable for toxicity, and 9 were evaluable for response. Among these, median follow-up was 3.5 months, and best overall response was stable disease in 5 patients and progression of disease in 4 patients. Median progression-free survival was 1.8 months. The most common treatment-related adverse events (grade > 2) were anemia, dyspnea, and hyperbilirubinemia. All patients had anemia (grades 1-3), with 33% having at least 1 dose reduction.

CONCLUSION

Oral ribavirin decreases p-eIF4E levels and is well-tolerated. However, a clear signal of efficacy in patients with recurrent and/or metastatic HPV-related cancers was not observed. (NCT02308241, NCT01268579).

HPV and Recurrent Respiratory Papillomatosis: A Brief Review

Recurrent Respiratory Papillomatosis (RRP) is a rare but severe manifestation of human papillomavirus (HPV). As our knowledge about HPV infections has expanded, it has become possible to understand the course of RRP disease and unravel plausible efficient methods to manage the disease. However, the surge in reports on HPV has not been accompanied by a similar increase in research about RRP specifically. In this paper, we review the clinical manifestation and typical presentation of the illness. In addition, the pathogenesis and progression of the disease are described. On the other hand, we discuss the types of treatments currently available and future treatment strategies. The role of vaccination in both the prevention and treatment of RRP will also be reviewed. We believe this review is essential to update the general knowledge on RRP with the latest information available to date to enhance our understanding of RRP and its management.

Experimental research on the therapeutic effect of MMR vaccine to juvenile-onset recurrent respiratory papillomatosis

OBJECTIVE

To evaluate the efficacy of MMR vaccine in the treatment of juvenile-onset recurrent respiratory papillomatosis as adjuvant therapy by experimental research.

METHODS

Thirty-one children with RRP were enrolled and assigned randomly to intervention group or control group. Fifteen subjects in intervention group were treated with local application MMR vaccine on the lesion after surgery; sixteen subjects in the control group were treated with surgical excision alone. The quantity of virus of positive specimens was measured by fluorescence quantitative polymerase chain reaction.

RESULTS

After treatment with MMR vaccine, viral load of intervention group was (9.56 ± 11.03) × 10⁸  copies/ml, that of control group was (22.01 ± 17.78) × 10⁸ copies/ml, and there was significant difference between the two groups (P = 0.040).

CONCLUSIONS

Local application MMR vaccine as adjuvant therapy can reduce HPV viral load significantly. It is suggested that the MMR vaccine may inhibit replication of HPV DNA, but the curative effect needs further confirmation.

Postoperative Systemic Acyclovir in Juvenile-Onset Recurrent Respiratory Papillomatosis: The Outcome

A prospective observational study was conducted consisting of 21 patients of Juvenile-onset recurrent respiratory papillomatosis, attending the Department of Otorhinolaryngology and Head Neck Surgery at our institution, who underwent surgical excision of the papillomas followed by oral acyclovir postoperatively. The study was aimed to observe the effect of systemic acyclovir on postoperative outcomes in children having recurrent respiratory papillomatosis undergoing primary surgical excision. It was observed that the mean interval between surgeries as well as the number of surgical interventions required was significantly lesser when acyclovir was used as a postoperative adjuvant than when surgery was done alone. Hence, the interval between successive surgeries, or in other words, the time interval between relapse of the disease could be prolonged significantly with the use of postoperative systemic acyclovir. Thus, the disease could be controlled for longer periods and repeated surgeries avoided.

Current and future management of recurrent respiratory papillomatosis

Objectives

Recurrent respiratory papillomatosis (RRP) is a chronic disease of the respiratory tract that occurs in both children and adults. It is caused by the human papillomavirus (HPV), in particular low‐risk HPV6 and HPV11, and aggressiveness varies among patients. RRP remains a chronic disease that is difficult to manage. This review provides perspectives on current and future management of RRP.

Results

The current standard of care is surgical excision, with adjuvant therapies as needed. Surgical management of RRP has evolved with the introduction of microdebriders and photoangiolytic lasers; the latter can now be used in the office setting. Numerous adjuvant pharmacologic therapies have been utilized with some success. Also, exciting preliminary data show that HPV vaccines may prolong the time to recurrence in the RRP population. There is also optimism that wide‐spread HPV vaccination could reduce RRP incidence indirectly by preventing vertical HPV transmission to newborns.

Conclusion

To date, the biology of RRP is not well understood, although it has been noted to become more aggressive in the setting of immune suppression. Additional research is needed to better understand immune system dysfunction in RRP such that immunomodulatory approaches may be developed for RRP management.

Level of Evidence

4

Treatment With Quadrivalent Human Papillomavirus Vaccine for Juvenile-Onset Recurrent Respiratory Papillomatosis: Case Report and Review of the Literature

Although juvenile-onset recurrent respiratory papillomatosis (JoRRP) generally involves a benign tumor on the larynx and other respiratory tract areas, almost all patients with this disease require repeated surgical intervention (to prevent airway obstruction during the course of illness) and various adjuvant therapies such as interferon, cidofovir, acyclovir, ribavirin, indole-3-carbinol, HspE7, mumps vaccine, photodynamic therapy, propranolol, cimetidine, and bevacizumab. Some case reports recently described the effectiveness of the quadrivalent human papillomavirus vaccine (HPV4) as an adjuvant therapy. On the basis of these reports, we administered HPV4 to a 2-year-old boy with JoRRP. However, no therapeutic effect was found. A review of the available literature revealed that current evidence for the effectiveness of therapeutic HPV4 and other adjuvant therapies for JoRRP is inconsistent. Therefore, the prophylactic use of currently available HPV vaccine for adolescents is the most effective strategy for preventing not only anogenital cancers but also genital warts, which might be a risk factor for JoRRP among their children in the future.

Comparison of cidofovir and the measles, mumps, and rubella vaccine in the treatment of recurrent respiratory papillomatosis

We conducted a retrospective study of the use of cidofovir and the measles, mumps, and rubella (MMR) vaccineas adjunctive treatments to lesion debridement in patients with recurrent respiratory papillomatosis (RRP). Our study population was made up of 15 children-7 boys and 8 girls, aged 1 to 16 years at diagnosis (mean: 6.2)-with pathologically confirmed RRP who had been followed for at least 1 year. In addition to demographic data, we compiled information on disease severity, the type of adjunctive treatment administered to each patient, the frequency of debridements, the length of observation, and remission rates. Of the 15 patients, 5 had been treated with cidofovirafter debridement (cidofovir-only group), 6 were treated with MMR vaccine after debridement (MMR-only group), 3 were treated with one and later switched to the other based on parental preference, and 1 received neither treatment, only debridement. The initial mean Derkay disease severity scores were 12.6 for the cidofovir-only group and 11.0 for the MMR-only group (p = 0.61). The cidofovir-only patients underwent an average of 11.8 adjunctive treatments and the MMR-only patients an average of 17.7 (p = 0.33). The average duration of observation was 44.0 months in the cidofovir-only group and 64.7 months in the MMR-only group (p = 0.29). Remission rates were 20% in the cidofovir-only group and 50% in the MMR-only group (p = 0.54). Our study found insufficient evidence of any significant differences between cidofovir and the MMR vaccinein terms of the number and frequency of adjunctive treatments and the rates of remission.

Histologic Review of Cidofovir-Treated Recurrent Respiratory Papillomatosis

Objectives

Recurrent respiratory papillomatosis is currently the most common lesion of the larynx in children. The course of the disease is variable and often requires repetitive surgical interventions to maintain the airway. The predominant concern for disease progression is the possibility of spread to the tracheobronchial tree, as this increases the rates of morbidity and mortality. Cidofovir is an antiviral drug with activity against members of the DNA virus family. Development of local malignant change secondary to use of cidofovir has been a concern. The histopathologic findings from biopsy specimens from children treated with cidofovir have not been previously reported.

Methods

We performed a retrospective review of pediatric operative histologic biopsies and charts of patients treated with intralesional cidofovir and untreated study controls from January 1, 1995, through November 1, 2001.

Results

Ninety-six specimens were evaluated by 2 blinded pathologists. No cases of dysplasia were identified. The most commonly identified finding was an increased nucleus-to-cytoplasm ratio in 8 of 95 cases (8.4%). No cases of abnormal mitoses, prominent nucleoli, or cellular or nuclear enlargement were found.

Conclusions

This is the first report of pathologically evaluated recurrent respiratory papillomatosis specimens taken before and after treatment with intralesional cidofovir. No dysplasia was identified, and there were no significant dysplastic changes in the specimens analyzed.

Treatment of human papillomavirus infection with interferon alpha and ribavirin in a patient with acquired aplastic anemia

Genital warts caused by human papillomavirus (HPV) are the most frequent sexually transmitted infection. We describe a case of severe perianal and genital HPV infection in a patient with acquired aplastic anemia, unresponsive to traditional therapies and treated effectively with a combination of interferon and ribavirin.

Recurrent respiratory pappillomatosis: national registry

Recurrent respiratory pappillomatosis is a rare condition with unpredictable nature of disease presentation and behaviour. This write up highlights our institutional experience and the importance of having a national registry for the same. An existing registry created by our team is introduced to facilitate maximum participation by our national otolaryngologists.

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.

[Laryngeal papillomatosis: etiology, diagnostics and therapy]

Papillomas are rare tumors that originate from the mucosa. They may appear in the nose, paranasal sinuses, oral cavity, larynx, trachea, or the skin. Papillomas are mainly asymptomatic and are therefore mostly diagnosed coincidentally. In contrast, laryngeal papillomatosis may cause stridor, dyspnoea, and hoarseness. A viral cause of the disease seems likely, especially human papilloma virus. Mechanical irritation is also a possible reason when the nose, oral cavity, or oropharynx is affected. All papillomas, independent of their origin, may recur, and have the possibility of malignant degeneration in common. The therapy of choice is complete surgical excision. Regarding laryngeal papillomatosis, laser vaporisation or excision using the CO(2)laser is recommended. Because retreatments using conventional modalities are frequently necessary, especially in the case of laryngeal papillomatosis, adjuvant therapies are applied with the aim of reducing the recurrence rate and prolonging the interval between treatments.

Recurrent respiratory papillomatosis: a review

Recurrent respiratory papillomatosis (RRP), which is caused by human papillomavirus types 6 and 11, is the most common benign neoplasm of the larynx among children and the second most frequent cause of childhood hoarseness. After changes in voice, stridor is the second most common symptom, first inspiratory and then biphasic. Less common presenting symptoms include chronic cough, recurrent pneumonia, failure to thrive, dyspnea, dysphagia, or acute respiratory distress, especially in infants with an upper respiratory tract infection. Differential diagnoses include asthma, croup, allergies, vocal nodules, or bronchitis. Reports estimate the incidence of RRP in the United States at 4.3 per 100,000 children and 1.8 per 100,000 adults. Infection in children has been associated with vertical transmission during vaginal delivery from an infected mother. Younger age at diagnosis is associated with more aggressive disease and the need for more frequent surgical procedures to decrease the airway burden. When surgical therapy is needed more frequently than four times in 12 months or there is evidence of RRP outside the larynx, adjuvant medical therapy should be considered. Adjuvant therapies that have been investigated include dietary supplements, control of extra-esophageal reflux disease, potent antiviral and chemotherapeutic agents, and photodynamic therapies; although several have shown promise, none to date has "cured" RRP, and some may have serious side effects. Because RRP, although histologically benign, is so difficult to control and can cause severe morbidity and death, better therapies are needed. The potential for a quadrivalent human papilloma vaccine is being explored to reduce the incidence of this disease.

Antiviral agents for the treatment of recurrent respiratory papillomatosis: a systematic review of the English-language literature

OBJECTIVE

To determine the efficacy of antiviral agents for recurrent respiratory papillomatosis (RRP) in children and adults.

STUDY DESIGN

Systematic review to include randomized controlled trials (RCTs), comparative studies (historical and/or nonrandomized), case series, and case reports.

RESULTS

Twenty-six original studies were included (one case-control series, 21 noncomparative trials, four case reports, and no RCTs). Meta-analysis was not possible. The antiviral modalities included acyclovir, ribavirin, intravenous cidofovir, and intralesional cidofovir injections. The strongest evidence was for intralesional cidofovir, with 17 studies including 158 patients. Of these, 90 patients (57%) demonstrated complete resolution, 55 patients (35%) a partial response, and 13 patients (8%) showed no improvement.

CONCLUSIONS

Insufficient evidence from controlled trials exists for reliable conclusions, but several series indicate intralesional cidofovir may have some efficacy. A well-designed placebo-controlled, double-blinded, randomized controlled trial is needed.

SIGNIFICANCE

This study provides the background for future study design and a comprehensive review of the available evidence.

Recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis is a frustrating and challenging disease for surgeons, patients, and patients' families. Although the voice and airway manifestations are managed surgically, a "cure" for this disease remains elusive. In this edition of the "Seminar Series," we endeavor to review the current literature regarding the epidemiology, etiology, clinical manifestations, and surgical and medical treatments of this disorder. The key to future management of recurrent respiratory papillomatosis may lie in its prevention, if current efforts to develop an effective vaccine come to fruition.

Estudo do efeito do Cidofovir na papilomatose laríngea recorrente em crianças: relato preliminar

OBJETIVO: Demonstrar o efeito do uso do Cidofovir (aplicações locais) em crianças com papilomatose laríngea recorrente (PLR), respeitando um protocolo adotado desde 2002 na Disciplina de Otorrinolaringologia Pediátrica da UNIFESP. FORMA DE ESTUDO: Preliminar/clínico-prospectivo. MATERIAL E MÉTODO: Foram incluídas inicialmente 5 crianças portadoras de PLR acompanhadas no nosso ambulatório de laringologia pediátrica. Estas já haviam sido submetidas há no mínimo 3 cirurgias prévias ao uso do Cidofovir, com confirmação anatomopatológica de papilomatose (critérios inclusão) e não apresentavam alterações renais ou hepáticas (critérios de exclusão). O protocolo consistia em exérese das lesões e aplicação de até 3ml Cidofovir (7,5mg/ml). O ciclo de tratamento consistia de, no mínimo, 3 aplicações, e a qualquer sinal de recidiva iniciava-se novo ciclo de aplicações. RESULTADOS: Observamos nas 5 crianças estudadas que as recidivas das lesões (antes do Cidofovir) ocorreram em intervalos muito curtos (1 a 3 meses) necessitando de intervenção cirúrgica. Após inclusão no protocolo ocorreu mudança na evolução da doença nas 5 crianças, pois permanecem por período de no mínimo 1 ano sem necessidade de cirurgia. Nenhuma criança apresentou nenhum tipo de alteração nos exames laboratoriais, e nenhum tipo de efeito colateral local ou sistêmico com a injeção local de Cidofovir. Os resultados deste estudo preliminar nos permitem observar que a aplicação local de cidofovir utilizado em crianças com PLR, respeitando o protocolo adotado, demonstrou um bom controle das recidivas das lesões durante o período estudado.

Therapy for Recurrent Respiratory Papillomatosis

Human papillomaviruses types 6 or 11 are aetiological agents of recurrent respiratory papillomatosis, a disease characterized by benign exophytic tumours usually on the vocal cords. Surgery debulks the tumours, but these growths generally recur at regular intervals. Adjunct medical treatments, aimed at containing the virus and growth of tumours, include indole-3-carbinol or its dimer diindolylmethane, interferon, photodynamic therapy and others. Preventive and therapeutic vaccines hold promise for eliminating the virus.

Phase II double-blind, placebo-controlled study of the safety and efficacy of cidofovir topical gel for the treatment of patients with human papillomavirus infection

Genital condylomata acuminata are nonmalignant human papillomavirus (HPV)-induced tumors in which HPV types 6 and 11 are most commonly found. Usual treatments for condylomata acuminata are nonspecific and are based on the destruction or removal of infected tissue. These procedures are often painful and are characterized by a high relapse rate. We report here what is to our knowledge the first double-blind, placebo-controlled study of the use of cidofovir, a nucleotide analogue, for the treatment of genital papillomavirus infections. Thirty patients were enrolled in the study; 19 received cidofovir, and 11 received placebo. The median number of warts and the median baseline wart area were comparable for both groups. Nine (47%) of 19 patients in the cidofovir group had a complete response (total healing), compared with 0 of the patients in the placebo group (P=.006). None of the patients in the cidofovir group experienced progression of the disease, compared with 5 (45%) of 11 patients in the placebo group. The side effects recorded for both groups were comparable.

Successful ribavirin therapy for life-threatening laryngeal papillomatosis post liver transplantation

A 3-yr-old girl developed severe progressive juvenile laryngeal papillomatosis (JLP) 2 yr after liver transplantation (Tx) for biliary atresia. The papillomata were resistant to withdrawal of immunosuppression, to laser surgery, and to subcutaneous interferon (3 MU/m2, three times weekly), necessitating tracheostomy. Oral ribavirin therapy (25 mg/kg/day) in combination with no immunosuppression effectively prevented the rapid recurrence of JLP over 5 yr. Hence, oral ribavirin is a potentially useful therapy in this life-threatening situation and may also be of benefit in other children with severe JLP.

Recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is the most common benign neoplasm of the larynx in children. Despite its benign histology, RRP has potentially morbid consequences and is often difficult to treat because of its tendency to recur and spread throughout the respiratory tract. Long neglected from an epidemiological standpoint, recent initiatives to better understand this disease process have been launched through coordination between the Centers for Disease Control and Prevention and the American Society of Pediatric Otolaryngology. In this clinical review, I discuss what we currently know regarding the etiology, epidemiology, and transmission of this disease. Clinical features including pertinent aspects of the history, physical examination, airway endoscopy, and other considerations are highlighted. A detailed description of the surgical and anesthetic management of these challenging cases is presented. Adjuvant modalities of surgical and nonsurgical treatment and their indications are discussed. Ongoing research initiatives and the Practice Guidelines of the Recurrent Respiratory Papillomatosis Task Force are also included.

Recent advances in diagnosis and therapy of human papillomaviruses

Infection with human papillomavirus is extremely common throughout the world. Almost 50% of sexually active young women are infected with human papillomavirus and although most infections are transient, a subset has the potential to progress to invasive cancer. During the last 20 years, our understanding of the human papillomavirus life cycle and the role of human papillomavirus in human cancer has dramatically increased. Recent technological advances in human papillomavirus detection have provided the means to detect the presence of human papillomavirus with great sensitivity. In the context of patient care, there is still substantial debate regarding the optimal diagnostic and prognostic use of information derived from hybrid capture or polymerase chain reaction-based detection. The inventory of available treatment options is growing somewhat slowly. The most promising advances are being made in the clinical evaluation of candidates for prophylactic vaccination. This review is focused on the current status and future directions of prevention, diagnosis and therapy.

Pathogenesis and treatment of juvenile onset recurrent respiratory papillomatosis

Juvenile onset recurrent respiratory papillomatosis is the most common cause of laryngeal tumors in children. This disease is caused by infection of the human papillomavirus, a virus whose complete genetic structure is now known. New, more directed agents show promise for improved control of papillomatosis in preliminary studies. Concurrently, there is an increasing awareness of methods to reduce surgical morbidity. At present, the role of preventive efforts including elective caesarian section remains uncertain.

Therapeutic evaluation of compounds in the SCID-RA papillomavirus model

A previous study by Kreider (Kreider et al., 1979) indicated that rabbit skin, which had been transplanted to immunodeficient nude mice, could be successfully infected with cottontail rabbit papillomavirus (CRPV). We have extended this observation in developing a rodent model for evaluation of compounds for activity against the papillomaviruses. In this model (called the SCID-Ra model), rabbit ear skin is transplanted to the dorsum of SCID mice and allowed to heal for 3 weeks. Infection with CRPV by scarification leads to the growth of warty lesions within 2 3 weeks in >95% of the animals. Topical and/or systemic therapy can be initiated at various times post infection (PI). Weekly lesion scores are recorded and compounds are evaluated for their ability to suppress wart growth when compared to untreated control mice. Ribavirin, which has had a suppressive effect both in the clinic for the treatment of respiratory papillomatosis and on the growth of warts in the rabbit back model, was evaluated and showed significant anti-proliferative activity with oral dosing. Both antiviral and antiproliferative compounds including podophyllin and 5-fluorouracil, which have been used clinically for the treatment of human papillomavirus (HPV) infections, were evaluated in this model. The anti-mitotic compound, Navelbine (vinorelbine tartrate), which is used for the treatment of non-small cell lung carcinoma was evaluated in this system and showed significant inhibition of wart growth with somewhat less topical cytotoxicity when compared to podophyllotoxin.

Flash pump dye laser treatment of laryngeal papillomas

To evaluate the feasibility and safety of the flash pump dye (FPD) laser for the treatment of laryngeal papillomas, we performed a prospective nonrandomized trial comparing FPD and carbon dioxide (CO2) laser treatment of laryngeal papillomas in a tertiary care children's hospital. Nine patients from 2 to 20 years of age with severe recurrent laryngeal papillomas were enrolled in the study. All patients underwent CO2 laser debulking of papillomas on the left hemilarynx, with 8 W continuous or pulsed energy. The right hemilarynx was treated with the FPD laser with 12 to 77 pulses at 8 to 12 J, through a custom-designed 90 degrees firing fiber. An end point of blanching and purpura of the papillomas was used. The main outcome measures were the safety and ease of operation with the FPD laser, and decreased papilloma size based on visual inspection at 2 weeks postoperative and at the next laser procedure. Seven patients were irradiated I time with an FPD laser, and 2 patients 2 times. No intraoperative complications were noted. One patient developed early postoperative stridor. No patients described more discomfort, and 5 patients described their voice as being the same as or better than it was after prior CO2 laser procedures. Five patients had a 90% or more decrease in size of papillomas on the FPD-irradiated side 2 weeks postoperatively. Three patients had approximately a 50% reduction. A treatment effect was noted in all patients, and was similar to the results noted on the CO2 laser-treated side. Early results with FPD laser treatment of laryngeal papillomas suggest the protocol is relatively safe and feasible. Long-term results are pending. Because the FPD laser coagulates rather than vaporizing tissue, potential advantages may include decreased scarring relative to CO2 laser treatment, and improved patient and operator safety.

Molecular targets for human papillomaviruses: prospects for antiviral therapy

A substantial medical need exists for the development of antiviral medicines for the treatment of diseases associated with infection by human papillomaviruses (HPVs). HPVs are associated with various benign and malignant lesions including benign genital condyloma, common skin warts, laryngeal papillomas and anogenital cancer. Since treatment options are limited and typically not very satisfactory, the development of safe and effective antiviral drugs for HPV could have substantial clinical impact. In the last few years, exciting advances have been made in our understanding of papillomavirus replication and the effects that the virus has on growth of the host cell. Although still somewhat rudimentary, techniques have been developed for limited virion production in vitro offering the promise of more rapid advances in the dissection and understanding of the virus life cycle. Of the 8-10 HPV gene products that are made during infection, only one encodes enzymatic activities, the E1 helicase. Successful antiviral therapies have traditionally targeted viral enzymes such as polymerases, kinases and proteases. In contrast, macromolecular interactions which mediate the functions of E6, E7 and E2 are thought to be more difficult targets for small molecule therapy.

Treatment of severe laryngeal papillomatosis with intralesional injections of cidofovir [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine]

Respiratory papillomatosis is a rare and often severe disease, usually localized in the larynx. It may cause respiratory distress and even life-threatening obstruction of the airways. Treatment is generally based on the evaporation of the lesions with a CO2 laser, but microsurgery, cytotoxic and/or cytostatic drugs, interferons, and vaccines are also used. Cidofovir [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine] (HPMPC) was shown to suppress the growth of tumors induced by rabbit papillomavirus as well as human papillomavirus (HPV). The efficacy of cidofovir was assessed in 17 patients with severe respiratory papillomatosis. Cidofovir at a concentration of 2.5 mg/ml was injected directly in the different laryngeal papillomatous lesions during microlaryngoscopy under general anesthesia. Biopsies were taken before the treatment was started both for anatomopathology and viral typing. HPMPC kinetics in serum was monitored in three patients, the drug levels being determined by high-performance liquid chromatography. Complete disappearance of the papillomatosis was observed in 14 patients. Four patients relapsed and were successfully treated again with cidofovir. Of the three remaining patients, one progressed while under treatment with cidofovir, after an initial marked response. One patient had a partial remission and remained stable for more than 1 year after the last injection. He had a very aggressive and extensive disease originally. Finally, one patient was lost to follow-up after four injections. Intratumoral injections of cidofovir for the treatment of severe laryngeal papillomatosis is a powerful new therapeutic approach for this disease. Treatment was well tolerated, and no significant side effects were noted.

Recurrent respiratory papillomatosis

Juvenile-onset recurrent respiratory papillomatosis is a vertically transmitted disease caused by members of the human papilloma virus family. Characterized by the relentless growth of papillomatous lesions of the larynx, recurrent respiratory papillomatosis imposes significant morbidity on patients and strain on their families. Surgical excision of the papillomata remains the mainstay of therapy, but human papilloma virus DNA persists in adjacent, normal-appearing mucosa and likely serves as a reservoir for viral reseeding. Despite multiple adjuvant treatment modalities, a cure for recurrent respiratory papillomatosis remains elusive. Most afflicted patients eventually enter spontaneous remission, but some endure several hundred surgical procedures before this welcome respite.

Role of cesarean section in prevention of recurrent respiratory papillomatosis--is there one?

Recurrent respiratory papillomatosis (RRP) is a benign yet aggressive neoplasm that produces considerable morbidity in children. Previous studies have linked RRP in children to mothers with genital tract human papillomavirus infections (HPV). Risk factors for vertical transmission have not been well identified. Controversy exists among obstetricians and otolaryngologists regarding the role of cesarean section in preventing the transmission of HPV disease from mother to child. We address this issue by presenting the results of a national survey of otolaryngologists, the American College of Obstetrics and Gynecology position statement, the relevant literature regarding the association between RRP and maternal HPV, and the proposed mechanisms for HPV transmission at birth. We postulate a very limited role for cesarean section in preventing transmission of RRP, given our present knowledge of this disease.

An unusual reason for obstructive sleep apnea in a boy with hemophilia B: supraglottic papilloma

An unusual cause of obstructive sleep apnea in a boy with hemophilia B who was urgently intubated during the night because of suspected bleeding into the airway is analysed. The cause of airway obstruction was a floating papilloma hanging from false cord. At inspirium the tumor was moving immediately above the vocal cords. This was manifested during sleep by noisy snoring and numerous apneic pauses. When the child was awake he had no respiratory problems. After the tumor was removed, the boy breathed freely during sleep. However, the papillomas recur in various parts of the larynx and repeated surgical treatment by factor IX replacement: therapy is necessary.

Topical CTC-96 accelerates wart growth in rabbits infected with cottontail rabbit papillomavirus

CTC-96, a cobalt containing complex, was tested as a putative topical therapeutic agent for the treatment of papillomavirus-induced tumors in our cottontail rabbit papillomavirus (CRPV)-rabbit model system. Following experimental infection of domestic rabbits with CRPV, CTC-96 was applied to infection sites twice daily, 5 days a week for a total of 8 weeks. Two levels of concentrations of aqueous CTC-96 were compared to placebo control-treated animals. With increasing dose of CTC-96 we observed tumors earlier, larger, and more often across eight infected sites on each animal.