Table 1

Study and sample characteristics of included studies

First author, yearInterventions
(IFN dosing group)
Patients randomised (N)Localisation of wartsAge, (year, mean)Female (n/N (%))No of warts (mean (SD))Previous treatment (n/N (%))
Alpha-IFN
Petersen et al 3 5 MIU IFN-alpha 2b s.c. 3× per week (high dose) for 4 weeks after laser operation32Penile 18, vulvar 8, perianal/intra-anal 13, vagina/portio 32710/32 (31%)0–5 warts: 6
6–10 warts: 10
11–50 warts: 14
>50 warts: 2
Podophyllin 32, surgery 17, cryotherapy 5
 Placebo s.c. 3× per week for 4 weeks after laser operation23Penile 13, vulvar 10, perianal/intra-anal 11, vagina/portio 3239/23 (39%)0–5 warts: 3
6–10 warts: 8
11–50 warts: 9
>50 warts: 3
Podophyllin 23, surgery 17, cryotherapy 3
Eron et al 9 3 MIU IFN-alpha 2a s.c. 3× per week for 8 weeks (high dose), treatment began within 2 weeks after removal of warts via cryotherapy in weekly intervals49Penile 19, vulvar 9, scrotal 1, perianal 2, perineal 4, multiple warts 14Median 2321/49 (43%)Median 6.832/49 (65%)
 Placebo s.c. 3× per week for 8 weeks, treatment began within 2 weeks after removal of warts via cryotherapy in weekly intervals48Penile 26, vulvar 4, scrotal 0, perianal 0, perineal 3, multiple warts 15Median 2513/48 (27%)Median 7.839/48 (81%)
Handley et al 10 3 MIU IFN-alpha 2a s.c. 3× per week in the first week (high dose), then IFN 2× per week and cryotherapy 1× per week for 6 weeks29Male: inner and outer prepuce, glans, penile shaft, perianal, anal canal, terminal urethra
Female: introitus, vulva, vaginal, perianal, anal canal
n.s.14/29 (48%)Median 10n.s.
Placebo s.c. on 3× per week in the first week, then placebo 2× per week and cryotherapy 1× per week for 6 weeks3122/31 (71%)Median 13
The Condylomata International Collaborative Study Group 19938 3 MIU IFN-alpha 2a s.c. 3× per week (high dose) for 4 weeks after CO2 laser vaporisation74Genital 37, perianal 5, both 32Median 2552/74 (70%)≤10 warts: 30
>10 warts: 24 not countable 20
n.s.
Placebo (vehicle) s.c. 3× per week for 4 weeks after CO2 laser vaporisation72Genital 36, perianal 0, both 36Median 2349/72 (68%)≤10 warts: 30
>10 warts: 23 not countable 19
Armstrong et al 7 3 MIU IFN-alpha 2a s.c. 3× per week (high dose) for 1 week, then 2× per week IFN plus podophyllin for 6 weeks61External genitalia and/or perianal area, some patients with internal wartsn.s.26/61 (43%)14.2 (12.6)None
(inclusion criterion)
Placebo s.c. 3× per week for 1 week, then 2× per week placebo plus podophyllin for 6 weeks6341/63 (65%)19.7 (18.6)
Armstrong et al 6 3 MIU IFN-alpha-2a s.c. 3× per week (high dose) for 10 weeks in combination with ablative therapy83Genital 50, perianal 7, both 25n.s.n.s.1–5 warts: 21
6–10 warts: 22
11–15 warts: 7
16–20 warts: 7
>20 warts: 6 not countable 19
n.s.
1 MIU IFN-alpha-2a s.c. 3× per week (low dose) for 10 weeks in combination with ablative therapy85Genital 54, perianal 7, both 231–5 warts: 17
6–10 warts: 16
11–15 warts: 15
16–20 warts: 4
>20 warts: 11 not countable 21
Placebo s.c. 3× per week for 10 weeks in combination with ablative therapy81Genital 52, perianal 7, both 221–5 warts: 14
6–10 warts: 20
11–15 warts: 9
16–20 warts: 6
>20 warts: 6 not countable 26
Hohenleutner et al 4 1 MIU IFN-alpha 2b s.c. for 6 consecutive days (low dose), with another 6-day treatment cycle after 2 weeks. Treatment started immediately after CO2 laser ablation.19Perigenital, perianal, intra-anal, intravaginal29 (range 18–52)5/19 (26%)n.s.n.s.
No treatment after CO2 laser ablation1628 (range 22–38)5/16 (31%)
Roemisch et al 25 3 MIU IFN-alpha 2a s.c. in three cycles of 5 consecutive days with 2 weeks without treatment in between (high dose), starting after laser treatment24
(1:1 randomisation ratio assumed)
Vulva 21, vagina 6, portio 8, perianal 11, rectum 226.7All femalen.s.7/24 (29.2%)
1 MIU IFN-alpha 2a s.c. in three cycles of 5 consecutive days with 2 weeks without treatment in between (low dose), starting after laser treatment
Beta-IFN
Kokelj et al 2 3 MIU IFN-beta 1× per day for 10 days (very high dose) after diathermocoagulation
(after 1 month of follow-up all patients were treated with monthly diathermocoagulation if necessary)
26Glans, coronal sulcus, inner surface of the prepuce and shaft of the penis34 (range 20–53)All malen.s.n.s.
3 MIU IFN-beta 1× per day for 10 days, after 1 month treated with electrocautery2531 (range 19–54)
No treatment plus diathermocoagulation
(after 1 month of follow-up all patients were treated with monthly diathermocoagulation if necessary)
3334 (range 23–61)
Bonnez et al 24 2 MIU/m² IFN-beta 3× per week (high dose), cryotherapy in 10-day intervals, both for 6 weeks25Men: penile 88.7%, foreskin 5.2%, glans 2%, pubis and groin 1.6%, scrotum 0.8%, urethral meatus 0.4%
Women: labia minora and clitoris 36.1%, labia majora 23.9%, introitus 18.7%, perianal 14.2%, pubis and groin 7.1%
26.76/25 (24%)Median 524.5%
4 MIU/m² IFN-beta three times a week (very high dose), cryotherapy in 10-day intervals, both for 6 weeks2525.39/25 (36%)Median 8.518.4%
Gamma-IFN
Zouboulis et al 11 0.75 MIU IFN-gamma s.c. 1× per day for 7 days (low dose), beginning after ablative therapy (electrocautery or CO2 laser)10Penis or vulva 1, perianal/intra-anal 3, genital and anal 6Median 272/10 (20%)n.s.All (inclusion criterion)
 No treatment after ablative therapy (electrocautery or CO2 laser)10Penis or vulva 1, perianal/intra-anal 2, genital and anal 5Median 282/10 (20%)
Direct comparison of alpha-, beta- and gamma-IFN
Bonnez et al 5 2 MIU/m² IFN-alpha n1 s.c. 3× per week (high dose), cryotherapy in 10-day intervals, both for 6 weeks36Men: penile shaft 75.1%, foreskin 11.3%, pubis and groin 7.2%, glans 2.1%, anus 2.0%, urethral meatus 0.4%
Women: anus 31.3%, labia majora 28.8%, labia minora/clitoris 21.2%, introitus 12.6%, pubis and groin 6.1%
26.35/36 (14%)Median 1133.3%
2 MIU/m² IFN-beta s.c. 3× per week (high dose), cryotherapy in 10-day intervals, both for 6 weeks4028.17/40 (18%)Median 837.5%
2 MIU/m² IFN-gamma s.c. 3× per week (high dose), cryotherapy in 10-day intervals, both for 6 weeks3728.55/37 (14%)Median 927.0%
Placebo s.c. 3× per week, cryotherapy in 10-day intervals, both for 6 weeks3830.17/38 (18%)Median 1023.7%
  • IFN, interferon; MIU, million International Units, s.c., subcutaneously, n.s., not stated.