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PubMed1999

A randomized, controlled, safety study using imiquimod for the topical treatment of anogenital warts in HIV-infected patients. Imiquimod Study Group.

OBJECTIVE: To assess the safety of imiquimod, an immune response modifier, in the topical treatment of external anogenital warts in HIV-infected patients. SETTING: Clinical sites in the United Kingdom (eight) and the United States (five). DESIGN: A prospective, randomized, double-blind, vehicle-controlled study of imiquimod 5% cream or vehicle applied for 8+/-2 h three times per week for a maximum of 16 weeks in HIV-seropositive males (n = 97) and females (n = 3) aged 18 years or more with clinically diagnosed external anogenital warts, CD4 T lymphocyte count of > or = 100 x 10(6) cells/l and Karnofsky score > or = 70. MAIN OUTCOME MEASURES: Safety was assessed through the incidence and severity of local skin reactions and other adverse events, and through clinical laboratory tests. Wart clearance was documented by two-dimensional measurements of warts and by photography. RESULTS: Among the patients treated with imiquimod (n = 65) and vehicle (n = 35), the most common local skin reaction was erythema, (41.9 and 26.7%, respectively) and the incidence of patients reporting at least one adverse event was 69.2 and 65.7%, respectively. No clinically meaningful differences or changes in laboratory values were observed between treatment groups, nor were drug-related adverse effects observed in regard to HIV disease. While there was no significant difference between treatment groups in the number of patients who totally cleared their baseline warts (imiquimod 11% versus vehicle 6%, P = 0.488), more imiquimod-treated patients experienced a > or = 50% reduction in baseline wart area (38% versus 14%, P = 0.013). CONCLUSION: Most local skin reactions were mild and no adverse effects on HIV disease were observed. Topically applied imiquimod 5% cream reduced wart area and may have clinical utility in treating external anogenital warts in some HIV-infected patients.

Adjuvants, Immunologic↗

PubMed2006

Extramammary Paget's disease resistant to surgery and imiquimod monotherapy but responsive to imiquimod combination topical chemotherapy with 5-fluorouracil and retinoic acid: a case report.

Extramammary Paget's disease (EMPD) is an uncommon skin neoplasm that usually affects the elderly population and occurs in the genital, anorectal, or axillary areas. The recommended treatment of EMPD involves surgical excision, including Mohs micrographic surgery; however, surgery is associated with a high rate of recurrence. There have been reports of successful treatment of recurrence with monochemotherapy involving topical imiquimod 5% cream. We report a case of EMPD recurrence after surgery that was resistant to imiquimod monotherapy but that completely resolved after imiquimod was combined with topical 5-fluorouracil (5-FU) and retinoic acid. To our knowledge, this is the first reported case of imiquimod combination therapy with 5-FU and retinoic acid for the treatment of recurrent EMPD.

Administration, Cutaneous↗

PubMed1999

Topical imiquimod: a review of its use in genital warts.

UNLABELLED: Imiquimod is a topically active immunomodulatory agent that is formulated as a 5% cream for application by the patient. It is the first agent of its class, the immune response modifiers, to be used in the treatment of genital warts. In immunocompetent patients with genital warts, imiquimod stimulates the production of interferon-alpha and various other cytokines, and has indirect antiviral activity. In randomised, double-blind, vehicle-controlled clinical trials, complete clearance of warts occurred in 37 to 50% of immunocompetent patients with genital warts treated with imiquimod 5% cream 3 times a week for up to 16 weeks; partial clearance of warts (defined as a reduction in wart area of > or = 50%) was observed in 76% of recipients of imiquimod 5% cream. Rates of complete or partial clearance of warts were significantly higher in patients who applied imiquimod 5% cream 3 times a week than in recipients of imiquimod 1% or vehicle cream, each applied 3 times a week. A between-gender difference in clinical response to imiquimod 5% cream has been reported, with female patients experiencing higher rates of complete clearance of warts than males. Recurrence(s) of > or = 1 wart occurred in 13 to 19% of immunocompetent patients in whom complete clearance of warts had been achieved with imiquimod 5% cream. Imiquimod 5% cream also shows some clearance of warts in immunosuppressed HIV-infected patients with genital warts. Preliminary results of a vehicle-controlled study showed that the rate of partial clearance of warts (defined as a reduction in baseline wart area of >50%) [38%] was significantly higher with imiquimod 5% cream than with vehicle cream; however, the rate of complete clearance was not significantly higher than with vehicle cream. Imiquimod 5% cream is generally well tolerated by immunocompetent and HIV-infected patients. Local skin reactions (mainly mild or moderate), including erythema, itching and burning, are the most commonly reported adverse events, occurring in < or = 67% of patients applying imiquimod 5% cream 3 times a week. The incidence of adverse events is lower in patients applying the cream 3 times a week than with daily application. The incidence of systemic adverse events with imiquimod 5% cream (applied daily or 3 times a week) is similar to that of vehicle cream. The tolerability profile of imiquimod cream appears favourable compared with that of podophyllotoxin. CONCLUSION: Imiquimod 5% cream is a new therapeutic option for patients with genital warts. It produces clearance rates broadly similar to those of other treatment approaches and rates of wart recurrence compare favourably with those reported for established treatments. In contrast to most alternative treatment strategies. which are administered in the physician's office, imiquimod cream is a self-administered therapy for outpatient use.

Adjuvants, Immunologic↗

PubMed2006

Topical imiquimod treatment prevents UV-light induced loss of contact hypersensitivity and immune tolerance.

Imiquimod (1-(2-methylpropyl)-1H-imidazo[4,5-c]quinolin-4-amine) is a TLR7 agonist that induces cytokine production in TLR7 bearing antigen-presenting cells (APCs), including IL-12, a cytokine that has been demonstrated to be a critical effector molecule for contact hypersensitivity (CHS). To test our hypothesis that topical applications of imiquimod may protect the skin immune system against the deleterious effects of UV light exposures, we treated animals with this agent, or its vehicle or nothing before UV exposures. Although topical imiquimod exposures before UV light did not prevent the depletion of epidermal Langerhans cells, it did prevent the loss of CHS. IL-12 was important in the protective role of imiquimod in preventing UV-induced loss of CHS, as systemic treatment of mice with an anti-IL-12 p70 monoclonal antibody blocked the protective effects of imiquimod. Additionally, only imiquimod-treated mice were resistant to hapten-specific tolerance induction after UV irradiation at the site of the initial sensitization with the hapten 2,4 dinitro-1-fluorobenzene. To model for the effects of TLR7 activation on the UV effect on antigen-APCs, XS52 cell line was used to study this interaction in an in vitro model system. This cell line expressed mRNA for TLR7, downregulated IkappaB, phosphorylated c-Jun N-terminal kinase, and secreted cytokines after exposure to imiquimod or lipopolysaccharide. Activation of the TLR7 signaling pathway on XS52 before UV-light exposures enhanced IL-12p70 secretion by this cell line. Similarly, activation of TLR7 on XS52 before UV-light exposure also prevented the UV-induced loss of IFN-gamma triggering in T cells during an allogeneic mixed lymphocyte reaction. Imiquimod-treated, UV-irradiated XS52 triggered a more vigorous IFN-gamma production than did either imiquimod-treated XS52 or UV-irradiated XS52, again suggesting a synergy between the two treatments. Lastly, enriched lymph node CD11c+ APCs from mice treated with UV irradiation, imiquimod alone or the combination of UV irradiation and imiquimod indicated the same in vivo synergy between imiquimod irradiation and UV irradiation in enhancing IL-12p70 production. These data suggest that topical imiquimod applications may play a role in preventing UV-induced impairment of the skin immune system, which is thought to be one of the critical events that allow the development of UV-induced skin cancers.

Adjuvants, Immunologic↗

PubMed1994

Cytokine induction in mice by the immunomodulator imiquimod.

Imiquimod has been identified as a potent antiviral and antitumor agent in animal models. The biological activity associated with imiquimod has been attributed to its induction of interferon (IFN)-alpha. The present studies evaluated imiquimod administered orally for its ability to stimulate production of IFN and other cytokines in mice. The cytokine profile induced by imiquimod was compared with other known immunomodulators. Imiquimod was found to stimulate increased serum IFN in mice. Daily dosing of imiquimod for five consecutive days led to diminished production of IFN in mice as measured after the final dose. Elevated levels of serum tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 but not IL-1 alpha were found in serum from mice treated with imiquimod. Imiquimod produced significantly higher levels of IFN but lower levels of TNF and IL-6 and IL-1 alpha than lipopolysaccharide. Polyinosinic acid:polycytidylic acid induced significantly higher amounts of IFN but lower levels of TNF and IL-6 than imiquimod. Imiquimod stimulated significantly higher levels of IFN when compared with 2-amino-5-bromo-6-phenyl-4(3H)-pyrimidinone (ABPP) and similar levels of IFN when compared with tilorone. Neither ABPP nor tilorone induced TNF or IL-6. Finally, imiquimod stimulated TNF, IFN, and IL-6 production in cultures of mouse spleen and bone marrow cells. These studies demonstrate that imiquimod induces not only IFN but other cytokines as well, all of which may contribute to its biological activity.

Aminoquinolines↗

PubMed2005

Disease-independent skin recruitment and activation of plasmacytoid predendritic cells following imiquimod treatment.

BACKGROUND: Imiquimod, an immune response modifier that is used topically to treat different types of skin cancer, induces the production of proinflammatory cytokines that stimulate an antitumor immune response. We assessed characteristics of the imiquimod-induced immune activation in epithelial and lymphoproliferative neoplasias of human skin. We focused on plasmacytoid predendritic cells (PDCs), the primary producer of interferon alpha (IFN-alpha) after imiquimod activation in vitro. METHODS: We used Affymetrix oligonucleotide arrays to compare gene expression profiles from tumors from 16 patients, 10 with superficial basal cell carcinomas (sBCCs), five with cutaneous T-cell lymphomas (CTCLs), and one with Bowen's disease, before and after topical imiquimod treatment. We used quantitative immunohistochemistry with PDC-specific antibodies against BDCA-2 and CD123 to characterize the PDC population before and after imiquimod treatment in these specimens. Activation status of PDCs from four sBCC patients was assessed by intracellular IFN-alpha staining and flow cytometry. RESULTS: Expression of various IFN-alpha-inducible genes (e.g., CIG5, G1P2, OASL, IFIT1, STAT1, IFI35, OAS1, ISG20, MxA, and IRF7), the so-called IFN-alpha signature, was increased similarly in both sBCC and CTCL lesions after imiquimod treatment. PDCs were recruited and activated in both lesion types, and they produced IFN-alpha after imiquimod treatment in vivo (mean percentage of PDCs producing IFN-alpha = 14.5%, 95% confidence interval [CI] = 4.9% to 24%; range = 3.3%-27%, n = 4 lesions). Imiquimod induced similar immune activation patterns in all three diseases, and these patterns were associated with the number of PDCs recruited to the treatment site. Two imiquimod-treated sBCC patients who did not mount an inflammatory response to imiquimod and whose lesions lacked the IFN-alpha signature after treatment had fewer PDCs in treated lesions compared with other treated patients with such a response. CONCLUSIONS: Imiquimod induces immune activation patterns that relate to the number of the PDCs recruited to the treatment site, thus supporting the role of PDC in responsiveness to imiquimod in humans.

Adjuvants, Immunologic↗

PubMed1998

Imiquimod in clinical practice.

Applied topically, imiquimod induces the production of interferon-alpha plus other cytokines. Because intralesional interferon is effective in the treatment of condylomata acuminata (genital warts), topical imiquimod has also been investigated as a potential therapy for this condition. The dosing regimen found to best balance efficacy, side-effects and practicality is 5% imiquimod cream applied overnight by the patient three times weekly until warts clear, for up to 16 weeks. The largest double-blind trial to examine this protocol involved 311 patients with external anogenital warts who were randomized to use imiquimod 5% cream, imiquimod 1% cream or vehicle cream. Evaluation of all patients given medication at any time showed that 50% of those who received 5% imiquimod experienced clearing of all baseline warts, as compared to 21% of those who used 1% imiquimod and 11% of those treated with vehicle. Overall, 5% imiquimod treatment was significantly more effective than vehicle (P < 0.0001). Excluding patients who discontinued medication for reasons unrelated to therapy (such as moving out of town or poor compliance), 56% of those who received 5% imiquimod experienced complete clearing of baseline warts. Clearing also occurred in 27% of those who received imiquimod 1%. Recurrence of baseline warts occurred in 13% of patients whose warts cleared with 5% imiquimod. When applied overnight at home three times each week, topical imiquimod 5% cream is an effective therapy with acceptable side-effects. The recurrence rate is low and further studies to specifically compare recurrence rates are warranted.

Adjuvants, Immunologic↗

PubMed2004

Imiquimod 5% cream for the treatment of actinic keratosis: results from two phase III, randomized, double-blind, parallel group, vehicle-controlled trials.

BACKGROUND: The immune system plays a critical role in the development and pathogenesis of actinic keratosis (AK). Imiquimod has been shown to stimulate the cutaneous immune response and be effective for the treatment of nonmelanoma skin cancers. OBJECTIVE: Two phase III, randomized, double-blind, vehicle-controlled studies evaluated the efficacy of imiquimod 5% cream compared with vehicle in the treatment of AK lesions on the face and balding scalp. METHODS: A total of 436 participants at 24 centers in the United States and Canada were randomized to either imiquimod 5% or vehicle cream. Study cream was applied one time per day, 2 days per week for 16 weeks. Clearance of AK lesions was clinically assessed at an 8-week posttreatment visit. RESULTS: The complete clearance rate was 45.1% for the imiquimod group and 3.2% for the vehicle group. The difference in complete clearance rates (imiquimod minus vehicle) was 41.9% with a 95% confidence interval of 34.9% to 49%. The partial (> or =75%) clearance rate was 59.1% for the imiquimod group and 11.8% for the vehicle group. The difference in partial clearance rates (imiquimod minus vehicle) was 47.3% with a 95% confidence interval of 39.5% to 55.1%. The median percent reduction in AK lesions was 83.3% for the imiquimod group and 0% for the vehicle group. Local skin reactions were common. Severe erythema was reported by 17.7% of participants who received imiquimod and 2.3% of participants who received vehicle. Overall, imiquimod was very well tolerated. CONCLUSION: Imiquimod 5% cream used 2 times per week for 16 weeks is an effective and well-tolerated treatment for AK.

Adjuvants, Immunologic↗

PubMed1998

Treatment of genital warts with an immune-response modifier (imiquimod).

BACKGROUND: Genital warts are a common sexually transmitted disease caused by human papillomavirus. Imiquimod is a novel immune-response modifier capable of inducing a variety of cytokines, including interferon alfa, tumor necrosis factor-alpha, as well as interleukins 1, 6, and 8. In animal models imiquimod has demonstrated antiviral, antitumor, and adjuvant activity. In vitro, imiquimod has no antiviral or antitumor activity. OBJECTIVE: Our purpose was to determine the safety and efficacy of topical imiquimod for the treatment of external genital warts. METHODS: This prospective double-blind, placebo-controlled, parallel design clinical trial was performed in three outpatient centers, a public health clinic, a university-based clinic, and a private practice. One hundred eight patients with external genital warts (predominantly white men) were entered into the trial. Fifty-one patients were randomly selected to receive 5% imiquimod cream; 57 patients were randomly chosen to receive placebo cream. Study medication was applied three times weekly for up to 8 weeks. Patients whose warts cleared completely were observed for up to 10 weeks to determine recurrence rates. RESULTS: In the intent-to-treat analysis, the warts of 37% (19 of 51) of the imiquimod-treated patients and 0% (0 of 57) of the placebo group cleared completely (p < 0.001). In addition, many patients experienced a partial response. A reduction in baseline wart area of 80% or more was observed in 62% of imiquimod-treated patients (28 of 45) and 4% of the placebo group (2 of 50) (p < 0.001); a 50% reduction or more in wart area was noted in 76% of imiquimod-treated patients (34 of 45) and 8% of placebo recipients (4 of 50) (p < 0.001). Of imiquimod-treated patients whose warts cleared completely and who finished the 10-week follow-up period, 19% (3 of 16) experienced recurrences of warts. Imiquimod-treated patients experienced a significantly greater number of local inflammatory reactions than the placebo group. Symptoms and signs associated with the local inflammatory reactions included itching (54.2%), erythema (33.3%), burning (31.3%), irritation (16.7%), tenderness (12.5%), ulceration (10.4%), erosion (10.4%), and pain (8.3%). There were no differences in systemic reactions or laboratory abnormalities between treatment groups. CONCLUSION: Topical 5% imiquimod cream appears to have a significant therapeutic effect in the treatment of external genital warts.

Adjuvants, Immunologic↗

PubMed2001

Reduction of recurrent HSV disease using imiquimod alone or combined with a glycoprotein vaccine.

The aim of this study is to evaluate the effects of an immune modulator, imiquimod, given alone or in combination with an HSV vaccine on HSV immune responses and as immunotherapy of a genital recurrence model. After recovery from primary genital HSV infection, animals were randomized to placebo, 21 days of imiquimod plus a placebo vaccine, or 21 days of imiquimod plus an HSV-2 glycoprotein vaccine. Placebo or HSV vaccine was given in the footpad on days 16 and 37 after HSV-2 genital inoculation. Daily imiquimod or placebo was given subcutaneously in the shoulder on days 16 through 37. Genital recurrences were monitored and HSV specific NK activity, IL-2 response and ELISA antibody were assayed. For the entire 15 week observation period, imiquimod alone reduced recurrences 62.6%, while addition of HSV vaccine to imiquimod reduced recurrences 80.6% compared to placebo/placebo. The duration of significant recurrence reduction was more notable with the addition of vaccine. Imiquimod alone significantly reduced the weekly HSV recurrent disease in the first 10 weeks (53-94% reduction, mean 75.9%), as did imiquimod plus HSV-vaccine (71-98% reduction, mean 89.5%). In weeks 10-15, imiquimod alone reduced recurrences significantly only in week 10 (20-53% reduction, mean 33%), whereas the addition of vaccine extended the significant recurrence reduction to 14 weeks (44-71% reduction, mean 56.8%). The recurrence reduction is correlated to an increased HSV-induced in vitro IL-2 response and NK activity against HSV targets in treated groups. Both imiquimod and the imiquimod/vaccine combination significantly reduced genital HSV recurrences, but the combination extended the duration and extent of protection for recurrences compared to imiquimod alone. Enhanced HSV specific immune responses correlated to the protection.

Adjuvants, Immunologic↗

PubMed2002

A randomized, double-blind, vehicle-controlled study to assess 5% imiquimod cream for the treatment of multiple actinic keratoses.

BACKGROUND: Actinic keratoses (AKs) are precancerous epidermal lesions found most frequently on areas of the skin exposed to the sun. Several case studies published recently have indicated that 5% imiquimod cream, currently licensed for the treatment of genital warts, may be an effective treatment for AK. OBJECTIVE: To assess the efficacy and safety of imiquimod for the treatment of AK. DESIGN: Patients in this randomized, double-blind, vehicle-controlled study applied 5% imiquimod cream or vehicle to AK lesions 3 times per week for a maximum of 12 weeks or until lesions had resolved. In the event of an adverse reaction, application of imiquimod was reduced to 1 or 2 times per week. Rest periods were also allowed if necessary. SETTING: A specialized outpatient dermatology clinic within a state-funded hospital in Germany. PATIENTS: The study population was aged 45 to 85 years. Of 52 patients screened, 36 men and women with AK confirmed by histological diagnosis were enrolled. Patients were excluded from the study if they did not have a histological diagnosis for AK, if they were older than 85 years, or if they did not comply with the protocol. All patients had responded to a notice asking for volunteers. MAIN OUTCOME MEASURES: The number and appearance of lesions were evaluated before, during, and after treatment. All adverse effects were recorded. RESULTS: Lesions treated with 5% imiquimod cream were clinically cleared in 21 (84%) of 25 patients and partially cleared in 2 (8%). Clearance was histologically confirmed 2 weeks after the last application of imiquimod in all patients clinically diagnosed as lesion free. Only 10% of patients treated with imiquimod were clinically diagnosed with recurrence 1 year after treatment. No reduction in the size or number of AK lesions was observed in vehicle-treated patients. Adverse effects reported by patients treated with imiquimod included erythema, edema, induration, vesicles, erosion, ulceration, excoriation, and scabbing. However, imiquimod was well tolerated since all patients completed the 12-week treatment. Only a few, mild adverse reactions to the vehicle cream were reported. CONCLUSION: Application of 5% imiquimod cream for 12 weeks is an effective and well-tolerated treatment for AK.

Adjuvants, Immunologic↗

PubMed2004

C/EBPbeta activity and HPV-16 E6/E7 mRNA expression are not altered by imiquimod (ALDARA) in human cervical cancer cells in vitro.

OBJECTIVE: The purpose of this study was to determine the potential relationship between imiquimod and C/EBPbeta by investigating the extent to which imiquimod could alter C/EBPbeta binding activity to known sequences of the HPV-16 NCR, which could lead to the repression of HPV-16 E6/E7 oncogene expression, possibly impacting a major mechanism by which HPV causes cellular transformation. METHODS: The effect of imiquimod treatment on C/EBPbeta binding activity to its consensus sequence as well as to two specific regions of the HPV-16 NCR was determined by electromobility shift assay (EMSA) in CaSki cervical cancer cells. HPV-16 E6/E7 gene expression was evaluated by RNase protection assay (RPA) in CaSki and in W12-E cells treated with imiquimod. In addition, C/EBPbeta mRNA expression and protein production in response to imiquimod were evaluated by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting, respectively, in the cervical cancer cell lines, CaSki, HeLa, and C33A. RESULTS: C/EBPbeta binding activity, mRNA expression, and protein production remained unchanged with imiquimod treatment. Initially, HPV-16 E6/E7 expression appeared to be increased with imiquimod treatment in CaSki cells, but this effect was not reproducible. HPV-16 E6/E7 expression was not reproducibly altered with imiquimod treatment in W12-E cells. CONCLUSION: While these results indicate that imiquimod does not alter C/EBPbeta binding activity, nor does it appear to decrease HPV-16 E6/E7 oncogene expression in vitro, it remains possible that imiquimod may have utility in treating cervical dysplasia or cervical cancer via another mechanism.

Aminoquinolines↗

PubMed1998

Self-administered topical 5% imiquimod cream for external anogenital warts. HPV Study Group. Human PapillomaVirus.

OBJECTIVE: To compare the safety and effectiveness of 5% and 1% imiquimod cream with vehicle cream in the treatment of external anogenital warts. DESIGN: Randomized, double-blind, placebo-controlled comparison that evaluated patients for total clearance of their warts. Patients who experienced total clearance were evaluated for recurrence in a 12-week follow-up. SETTING: Eleven ambulatory offices, including both private physician offices and referral medical centers. PATIENTS: Three hundred eleven healthy men and women aged 18 years or older with 2 to 50 external anogenital warts were recruited from the practices of investigators, referring physicians, and advertisements. Eighty-two additional patients were screened but did not qualify. Four patients discontinued use of the medication because of adverse effects. INTERVENTIONS: Five percent imiquimod (Aldara) cream, 1% imiquimod cream, or vehicle cream was applied to all external warts overnight 3 times each week for 16 weeks, or until all treated warts disappeared, whichever occurred first. MAIN OUTCOME MEASUREMENTS: The number of patients experiencing the elimination of all baseline warts and the recurrence rate of these warts. In addition, the reduction in baseline wart area the duration of therapy required to eliminate warts, and the frequency and severity of adverse reactions were principal measurements. RESULTS: In the intent-to-treat analysis, 54 (50%) of 109 patients who received 5% imiquimod cream, 21 (21%) of 102 of those who received 1% imiquimod cream, and 11 (11%) of 100 patients treated with vehicle cream experienced eradication of all treated baseline warts. The difference between the effectiveness of 5% imiquimod cream and the vehicle cream was statistically significant (P < .001). Of those patients whose warts cleared during therapy, 13% of patients who received 5% imiquimod experienced a recurrence of at least 1 wart. Recurrences occurred in none of the patients who used 1% imiquimod cream and in 10% of patients who used the vehicle cream. Local erythema was the most common adverse reaction, but the majority of patients in each group experienced no or only mild local inflammatory reactions. There were no differences in incidences of flulike symptoms among treatment groups. CONCLUSIONS: Five percent imiquimod cream is an effective and safe self-administered therapy for external anogenital warts when applied 3 times a week overnight for up to 16 weeks. The recurrence rate is low.

Adjuvants, Immunologic↗

PubMed1998

Cytokine induction in hairless mouse and rat skin after topical application of the immune response modifiers imiquimod and S-28463.

ALDARA (imiquimod cream 5%) recently became available for the treatment of genital and perianal warts; however, the topical mechanism of action of imiquimod is not fully understood. Imiquimod, and its analogs R-842, S-27609, and S-28463, are potent anti-viral and anti-tumor agents in animal models. Much of the biologic activity of these compounds can be attributed to the induction of cytokines, including interferon-alpha, tumor necrosis factor-alpha, interleukins-1, -6, -8, and others. This study was performed to characterize the response of mice and rats to topical application of imiquimod and S-28463 and also to evaluate these agents in cultures of murine and human skin cells. Topical administration of imiquimod or S-28463 to the flanks of hairless mice and rats leads to increases in local concentrations of interferon and tumor necrosis factor in the skin. The concentrations of interferon and tumor necrosis factor were higher at the site of drug application than in skin from the contralateral flank or skin from untreated animals. Interferon-alpha mRNA levels were also elevated in the skin of mice after topical application of either imiquimod or S-28463. In vitro, both imiquimod and S-28463 induced increases in interferon and tumor necrosis factor in cultures of cells isolated from hairless mouse skin. Imiquimod also increased interleukin-8 concentrations in human keratinocyte and fibroblast cultures, whereas S-28463 induced increases in tumor necrosis factor in fibroblast cultures. These results demonstrate that imiquimod and S-28463 stimulate production of cytokines in the skin after topical application, which may play a major role in its activity in genital wart patients.

Adjuvants, Immunologic↗

PubMed2005

Randomized, double-blind clinical trial of topical imiquimod 5% with parenteral meglumine antimoniate in the treatment of cutaneous leishmaniasis in Peru.

BACKGROUND: Current treatments for cutaneous leishmaniasis are limited by their toxicity, high cost, and discomfort and the emergence of drug resistance. New approaches, including combination therapies, are urgently needed. We performed a double-blind, randomized trial of therapy with parenteral antimony plus topical imiquimod, an innate immune-response modulator, versus therapy with antimony alone, in subjects with cutaneous leishmaniasis for whom an initial course of antimony therapy had failed. METHODS: Forty subjects with clinical resistance to antimony were recruited in Lima, Peru, between February 2001 and December 2002. All subjects received meglumine antimoniate (20 mg/kg/day im or iv) and were randomized to receive either topical imiquimod 5% cream (Aldara; 3M Pharmaceuticals) or vehicle control every other day for 20 days. Lesions and adverse events were evaluated during treatment and at 1, 2, 3, 6, and 12 months after the treatment period. RESULTS: The mean number of lesions was 1.2 per person; 71% of the lesions were facial and 76% were ulcerative. There were no major differences between the groups, and all but 2 subjects completed therapy. Mild adverse events were reported by 73% of the subjects, but only erythema occurred more commonly in the imiquimod group (P < or = .02). Lesions resolved more rapidly in the imiquimod group: 50% of the imiquimod group achieved cure at 1 month after the treatment period versus 15% of the vehicle cream group (P < or = .02); 61% of the imiquimod group at 2 months versus 25% of the vehicle cream group (P < or = .03); and 72% of the imiquimod group at 3 months versus 35% of the vehicle cream group (P < or = .02). Residual scarring in the imiquimod group was less prominent than in the vehicle cream group. CONCLUSIONS: Combined antimony plus imiquimod treatment was well tolerated, accelerated healing of lesions, and improved scar quality. This therapy may have particular advantages for subjects with facial lesions.

Adjuvants, Immunologic↗

PubMed2003

Tumor-selective induction of apoptosis and the small-molecule immune response modifier imiquimod.

BACKGROUND: The incidence of nonmelanoma skin cancer, basal cell carcinomas (BCCs), and squamous cell carcinomas (SCCs) is increasing, representing a major medical and economic problem. Imiquimod, a topical small-molecule immune response modifier, has shown efficacy toward BCC and actinic keratoses in clinical trials. Imiquimod acts both indirectly, via cytokine-mediated stimulation of cellular immune responses, and directly, through unknown mechanisms against tumor cells. We examined the mechanism by which imiquimod induces apoptosis in cancer cells. METHODS: Apoptosis was assessed by enzyme-linked immunosorbent assay, western blot analysis, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays in five SCC cell lines, HaCaT cells (a spontaneously immortalized human keratinocyte cell line), and normal keratinocytes treated with imiquimod, with its analog resiquimod, or with neither. Expression of death receptors, caspases, and cytochrome c in the apoptotic signaling cascade was analyzed using western blot and flow cytometric analyses. The functional relevance of imiquimod-induced cytochrome c release was assessed by transfection of HaCaT cells with Bcl-2. Apoptosis in BCCs in vivo was assessed by TUNEL assays of imiquimod-treated and untreated tumors from three patients. Differences between treated and untreated cells and tumors were determined using a two-tailed Student's t test. RESULTS: Imiquimod, but not resiquimod, induced apoptosis in all SCC cell lines and HaCaT cells. This induction involved activation of several caspases and Bcl-2-dependent cytosolic translocation of cytochrome c but was independent of the membrane-bound death receptors Fas, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-R1-R4 receptors, and tumor necrosis factor-R1 and -R2 receptors. Topical application of imiquimod to BCC tumors in vivo induced apoptosis. CONCLUSION: Imiquimod has the potential to induce apoptosis in skin cancer cells, possibly by circumventing mechanisms developed by malignant tumors to resist apoptotic signals.

Aminoquinolines↗

PubMed2005

Imiquimod 5% cream for the treatment of superficial basal cell carcinoma: results from a randomized vehicle-controlled phase III study in Europe.

BACKGROUND: Imiquimod is an immune response modifier that acts through toll-like receptor 7 to induce cytokine production and a subsequent innate and adaptive cell-mediated immune response. Clinical studies have demonstrated clinical and histological clearance of superficial basal cell carcinoma (sBCC) after treatment with imiquimod 5% cream. OBJECTIVES: To evaluate the safety and clinical efficacy of imiquimod (Aldaratrade mark; 3M Pharmaceuticals, St Paul, MN, U.S.A.) 5% cream for the treatment of sBCC in a multicentre, randomized, parallel, vehicle-controlled, double-blind, phase III clinical study conducted at 26 centres in Europe. METHODS: Subjects who had at least one histologically confirmed sBCC tumour were randomized to apply imiquimod or vehicle cream to the target tumour once daily, seven times per week (7 x/week) for 6 weeks. The target tumour location was identified with an indelible ink mark before treatment initiation. The treated tumour site was clinically assessed for treatment response at 12 weeks post-treatment and was then excised for histological evaluation. Efficacy assessments included the composite response rates (proportion of subjects with clinical and histological clearance) and response rates solely based on histology (proportion of subjects with histological clearance). Safety assessments, which included adverse events and scoring of local skin reactions (LSRs), were carried out throughout the study. RESULTS: In total, 166 subjects were enrolled in this study. For the intent-to-treat dataset, there was a statistically significant difference between imiquimod and vehicle groups for both composite clearance rates (clinical and histological assessments) and histological clearance rates. Composite clearance was demonstrated in 77% and 6% of subjects treated with imiquimod and vehicle cream, respectively. Histological clearance was demonstrated in 80% and 6% of subjects treated with imiquimod and vehicle cream, respectively. The most frequently reported safety findings were investigator-assessed LSRs and spontaneous reports by subjects of application site reactions, which occurred more frequently in the imiquimod group than in the vehicle group. CONCLUSIONS: Imiquimod 5% cream administered 7 x/week for 6 weeks is a safe and effective treatment for sBCC when compared with vehicle cream.

Adult↗

PubMed2005

Long-term clinical outcomes following treatment of actinic keratosis with imiquimod 5% cream.

BACKGROUND: The results from four phase III, randomized, vehicle-controlled studies showed that imiquimod 5% cream (imiquimod) was safe and effective in the treatment of actinic keratosis (AK). Patients applied imiquimod or vehicle cream to AK lesions on the face or balding scalp, dosing three times per week or two times per week for 16 weeks. OBJECTIVE: To obtain long-term safety follow-up data and estimate AK recurrence in patients who completely cleared their AK lesions in the treatment area at the 8-week post-treatment visit in the phase III studies. METHODS: One hundred forty-six patients from 30 study centers in the United States were evaluated for clinical evidence of AK, and safety data were collected. RESULTS: After a median follow-up period of 16 months, 24.7% (19 of 77) of the patients administered imiquimod three times per week and 42.6% (23 of 54) of the patients administered imiquimod two times per week had a recurrence of AK (the appearance of at least one AK lesion) in the original treatment area. The median number of AK lesions present was one lesion for both patients receiving imiquimod three times and those receiving imiquimod two times per week compared with a median of six lesions at baseline in the combined three times per week and two times per week phase III studies. There were no long-term safety issues, and the skin quality seen in the imiquimod-treated patients at the end of the phase III studies was maintained. CONCLUSION: One and a half years following treatment, imiquimod continued to provide a long-term clinical benefit in a majority of patients who experienced complete clearance of their AK lesions.

Adjuvants, Immunologic↗