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Antimitotics and Antifibrotics

Antimitotic and antifibrotic adjuncts to endoscopic urethral stricture management target the pathologic wound-healing cascade — fibroblast proliferation, collagen deposition, and spongiofibrosis — that drives recurrence after internal urethrotomy (IU) and dilation. Mitomycin C (MMC) has a favorable pooled recurrence signal, but heterogeneous small studies do not establish it as the preferred routine adjunct. Paclitaxel-coated balloon catheters (Optilume) are the only FDA-approved antimitotic device for anterior urethral strictures.[1][2][3]

This article is the hub for MMC, paclitaxel DCBs, and related antimitotic / antifibrotic adjuncts (HA/CMC, PRP, tamoxifen, and preclinical agents). For intralesional corticosteroid adjuncts (triamcinolone) — mechanistically distinct and covered separately — see Intralesional corticosteroids. For PRP-specific detail beyond this article, see Platelet-rich plasma. For the clinical condition, see Urethral stricture.

Why adjuncts are needed​

Internal urethrotomy and dilation are the most commonly performed procedures for urethral stricture disease but carry long-term success rates of only 0–9% for recurrent strictures.[4] Recurrence is driven by pathologic wound healing — excessive fibroblast proliferation, collagen deposition, and spongiofibrosis.[2] The AUA Urethral Stricture Disease Guideline Amendment 2023 states that clinicians may endoscopically inject pharmacologic agents at the time of direct visual internal urethrotomy (DVIU) to reduce recurrence risk, though the evidence remains limited.[3]

Pang 2021 European Urology systematic review + meta-analysis (26 studies, 13 adjuncts) — any adjunct reduced recurrence (OR 0.37; 95% CI 0.27–0.50; p < 0.001). Agent-specific signals:[1]

AgentIntralesional ORComment
Mitomycin C0.23 (0.11–0.48)Strongest signal of any adjunct
Paclitaxel DCBOR with separate RCT data (ROBUST III)FDA-approved
CorticosteroidsModest benefitSee Intralesional corticosteroids
CaptoprilSignal present, 61% pruritusTolerability problem

Mitomycin C — the best-studied antifibrotic adjunct​

Mechanism​

MMC is an alkylating agent derived from Streptomyces caespitosus that cross-links DNA, inducing fibroblast apoptosis and inhibiting fibroblast proliferation and collagen synthesis.[5][6] Rat urethral-stricture models show MMC decreases cell proliferation and DNA damage in the fibrotic compartment while permitting healthy re-epithelialization — these preclinical findings do not establish selective safety in healthy human tissue. MMC is a cytotoxic DNA-crosslinking drug; extravasation and tissue injury remain clinically important.[7]

Urethral stricture evidence​

StudynFinding
Mazdak 2007 RCT40Recurrence at 6 mo 10% MMC vs 50% control (p = 0.006) — the anchor RCT[8]
Irdam 2019 meta231 (3 RCTs)Fixed RR 0.32 (95% CI 0.19–0.54; p < 0.001) for recurrence[9]
Farrell 201744 recurrent bulbar / bulbomembranous (all prior failures)75% no further intervention after single DVIU + MMC; 92.5% after a second procedure; non-radiation 80.8% vs radiation 66.7%[10]
Farrell 201537 recurrent stricture / BNC75.7% no further surgery at 23 mo; non-RIS 84.6% vs RIS 54.5%[11]

Bladder-neck contracture and VUAS evidence​

StudyPopulationFinding
Vanni 201118 recurrent BNC72% patent after 1 procedure; 89% after 2 at 12 mo[12]
Rozanski 2021 multi-institutional86 recurrent BNC / VUAS65% after 1 procedure, 90% overall after repeat; non-radiated 94% vs radiated 76% (p = 0.04)[13]
Sourial 201729 recurrent post-RP VUAS79% patent at 12 mo after single MMC + dilation; 86% with salvage injection; 69% went on to successful anti-incontinence surgery[14]
TURNS — Redshaw 2015 (cautionary)Multicenter BNC cohort58% success after 1 procedure — lower than single-center series; 7% serious adverse-event rate (4 patients; 3 requiring / planning cystectomy)[15]

The AUA 2023 guideline specifically notes "conflicting data about the utility of Mitomycin-C for the treatment of recurrent vesicourethral stenosis, with further study necessary to validate its use."[3]

Historical study protocols — not standardized prescribing​

These protocols describe published studies, not interchangeable or recommended regimens. EAU guidance restricts intralesional adjuncts to clinical trials because dose, depth, volume and technique remain uncertain. Posterior stenosis carries particular necrosis/fistula risk; do not transfer anterior injection/incision patterns to VUAS.[36]

ProtocolDose / concentrationInjection sitesPost-procedure
Farrell / Levine10 mL of 0.4 mg/mL (4 mg total) in 0.2–0.4 mL aliquotsAt each cold-knife incision site (12, 3, 9 o'clock)CIC × 1 month[10][11]
Vanni / Buckley0.3–0.4 mg/mLTri- or quadrant cold-knife incisionsVariable[12]
Klein / Rusilko2 mg total in 5 mL sterile water5 and 7 o'clock incision sitesFoley catheter[16]
SourialMMC at 3, 6, 9 o'clockFollowed by dilation to 26FCystoscopic follow-up[14]
Mazdak original RCT0.1 mg submucosalAt urethrotomy siteStandard[8]

Safety​

  • Most series report no long-term complications attributable to MMC[10][11][13]
  • TURNS BNC series reported the key cautionary signal: 7% serious AE rate including 3 patients requiring or planning cystectomy/diversion[15]
  • Theoretical long-term concern for malignant transformation given DNA-damaging mechanism — not observed in clinical follow-up to date[5]
  • FAERS pharmacovigilance identified bladder perforation as a rare but serious signal — primarily reflecting intravesical instillation for bladder cancer rather than stricture injection[17]

Paclitaxel drug-coated balloons (Optilume)​

Mechanism​

Paclitaxel stabilizes microtubules → cell-cycle arrest → inhibited fibroblast proliferation and reduced collagen deposition. The Optilume DCB combines mechanical dilation with local paclitaxel delivery to a dilated stricture segment, preventing the usual post-dilation restenosis cascade.[18][19]

FDA status and guideline positioning​

  • FDA-approved for anterior urethral strictures
  • AUA 2023 guideline amendment recommends restricting DCBs to recurrent bulbar urethral strictures <3 cm in patients who have failed at least one prior DVIU / dilation[3]

Key evidence​

Trialn / DesignFinding
ROBUST III RCT (Elliott 2022)127 recurrent anterior strictures <3 cm1-year freedom from reintervention 83.2% DCB vs 21.7% control (p < 0.0001); 6-month anatomic success 75% vs 27%[18]
ROBUST III 3-year (Srikanth 2025)Same cohortDCB arm maintained 71% freedom from reintervention at 3 years in an extension without a contemporaneous three-year randomized control; exploratory subgroup comparisons do not prove equivalent efficacy[20]
TURNS real-world (Patel 2025)319 patients1-y recurrence-free survival 78.4% anterior / 75.8% posterior; strictures after hypospadias repair (HR 5.21) and 24F/3 cm DCB (HR 3.64) were recurrence predictors[21]
FIRST-CARE RCT (protocol 2026)Ongoing — treatment-naïve bulbar strictures ≤3 cmPrimary endpoint: freedom from reintervention at 12 months — tests Optilume as first-line rather than recurrent-stricture therapy[22]

For device-specific technical detail, see Drug-coated balloon therapy.

Hyaluronic acid / carboxymethylcellulose (HA/CMC)​

Mechanism: biophysical barrier gel — separates injured tissue surfaces, reduces adhesion formation, and modulates the wound-healing environment. Not a direct pharmacologic antifibrotic.

Evidence​

  • Chung 2013a multicenter RCT (n = 120, post-EIU) — recurrence at 24 wk 9.4% HA/CMC vs 22.9% control (p = 0.029); lower VAS pain scores (0.67 vs 3.60; p < 0.05)[23]
  • Chung 2013b multicenter RCT (n = 180, post-TURP) — stricture incidence 1.3% (1/80) vs 8.6% (7/81) control; lower pain[24]
  • Kim 2025 novel drug-injectable urethral catheter (NIUS) for HA delivery (n = 192 multicenter RCT) — improved patient satisfaction, less pain, fewer strictures vs conventional HA injection[25]

Systematic reviews classify HA/CMC alongside MMC as the best-supported adjuncts, with low to intermediate risk of bias.[2]

Platelet-rich plasma (PRP)​

Mechanism: autologous concentrated growth factors (PDGF, TGF-β, VEGF) promote organized tissue healing, normalize the collagen-I-to-collagen-III ratio (a marker of pathologic fibrosis), and reduce mucosal inflammation and spongiofibrosis.[26][27]

Evidence​

  • Rezaei 2019 RCT (n = 87) — IU + submucosal PRP vs IU + saline: 12-mo recurrence 9.09% vs 26.82% (p = 0.032); at 24 mo 21.95% vs 43.90%. The indexed abstract prints p = 0.34, whereas EAU reports p = 0.034; this discrepancy should not be used to claim that benefit necessarily disappeared at two years[28]
  • Animal studies confirm reduced mucosal inflammation, spongiofibrosis, and edema; normalized collagen-I:III ratio[26][27]

See Platelet-rich plasma for the broader PRP / PRF platform.

Oral systemic adjuncts​

  • Tamoxifen — SERM with ER-independent antifibrotic effects (TGF-β1 and collagen-synthesis inhibition).[29] Included in the Pang 2021 meta (n = 30) as an adjunct to IU; limited data. AEs: mild gynecomastia (6.7%), GI effects (6.7%)[1]
  • Deflazacort — oral corticosteroid; n = 36 in the meta-analysis; very limited evidence[1]

Preclinical and early-clinical agents​

AgentEvidenceStatus
Captopril (intraluminal ACE inhibitor)n = 37 clinical — 61% pruritus limits tolerability[1]Clinical but poorly tolerated
Bevacizumab (anti-VEGF)Rabbit model: inhibits fibrosis comparably to MMC[30]Preclinical
5-FluorouracilRabbit model: comparable antifibrotic to MMC[30]Preclinical
Pirfenidone (nanoparticle-loaded catheter)Rabbit model: reduced fibrosis; TGF-β1 inhibition[31]Preclinical delivery platform
Wnt/β-catenin inhibitors (ICG-001, PRI-724)Rat model: reduced collagen I and α-SMA[32]Preclinical
Glycyrrhizic-acid biogel scaffoldRabbit model: M2 macrophage polarization, reduced pro-inflammatory cytokines[33]Preclinical
Protein-nanofilm drug-eluting cathetersECM-homeostasis modulation; reduced collagen + enhanced MMP-1 degradation[34]Preclinical drug-delivery platform

Combination regimens​

Included in the Pang 2021 meta-analysis:[1]

  • Steroid + MMC + hyaluronidase (n = 103) — combines anti-inflammatory, antifibrotic, and tissue-penetration mechanisms
  • Triamcinolone + MMC + N-acetyl cysteine (n = 50) — adds antioxidant / mucolytic properties

Head-to-head comparisons between combination and single-agent regimens are lacking. The meta-analysis did not demonstrate superiority of combinations over the best single agents.

Corticosteroids — pointer only​

Triamcinolone and other corticosteroid adjuncts are covered fully in Intralesional corticosteroids. Summary pointers relevant here:

  • Zhang 2014 8-RCT meta — steroids prolong time to recurrence (10.14 vs 5.07 months) but effect wanes over time[35]
  • In the Pang 2021 network, MMC outperforms steroids on recurrence OR[1]
  • Practical: do not infer a routine injectable hierarchy from indirect pooled comparisons. Topical corticosteroids used with self-dilatation or for LS are distinct from intralesional post-DVIU injections.[36]

Comparative summary​

AgentRouteMechanismBest evidenceRecurrence signalKey limitation
Mitomycin CIntralesional / intraluminalDNA cross-link → fibroblast apoptosisPang 2021 meta; Mazdak RCT; Farrell seriesIntralesional OR 0.23TURNS 7% SAE in BNC; theoretical long-term DNA-damage concern[1][8][15]
Paclitaxel DCB (Optilume)Balloon-coatedMicrotubule stabilization → antiproliferativeROBUST III RCT + 3-y; TURNS real-world71% freedom from reintervention at 3 yUS label: adult male anterior ≤3 cm; guideline evidence best for recurrent bulbar <3 cm; repeat-use uncertainty[18][20]
Triamcinolone (intralesional)SubmucosalAnti-inflammatory + anti-collagenZhang 2014 metaProlongs time to recurrence; no long-term rate reductionEffect wanes; see Intralesional corticosteroids[35]
HA/CMCIntraluminal instillationBiophysical anti-adhesionChung 2013a, 2013b RCTs9.4% vs 22.9% recurrence at 24 wkNot a pharmacologic antifibrotic; instillation technique[23][24]
PRPIntralesionalGrowth factors → organized healingSingle RCT9.09% vs 26.82% at 12 moSmall study; abstract/guideline discrepancy in 24-mo p value[28]
TamoxifenOralTGF-β1 inhibitionSmall seriesLimited meta-analysis dataGynecomastia, GI[1][29]
CaptoprilIntraluminalACE inhibitor → TGF-βn = 37 clinicalSignal present61% pruritus — poorly tolerated[1]

Evidence Summary​

Indication / agentEvidence levelKey source
Any adjunct to DVIULevel 1 (systematic review + meta-analysis)Pang 2021 Eur Urol[1]
MMC for urethral strictureLevel 1 (meta of RCTs)Irdam 2019[9]; Mazdak 2007 RCT[8]; Farrell 2017[10]
MMC for BNC / VUASLevel 2–3 (retrospective multi-inst)Rozanski 2021[13]; Vanni 2011[12]; Sourial 2017[14]; TURNS cautionary[15]
Paclitaxel DCBLevel 1 (RCT)ROBUST III[18]; 3-year extension[20]; real-world TURNS[21]
HA/CMCLevel 1 (RCTs)Chung 2013a[23]; Chung 2013b[24]
PRPLevel 1 (single RCT)Rezaei 2019[28]
Paclitaxel first-lineOngoingFIRST-CARE protocol 2026[22]

Clinical Positioning​

  • Do not treat a favorable MMC meta-analysis as a routine-use recommendation. EAU advises intralesional post-DVIU agents within clinical trials and specifically cautions against posterior MMC outside trials. Small uncontrolled BNC/VUAS series cannot establish a standard dose or net benefit.[1][36]
  • TURNS reported serious tissue injury in 4/55 patients (7%). Three required or were planning cystectomy/diversion; this is not evidence that three had already undergone cystectomy. Radiation and extravasation concerns deserve explicit consent.[15]
  • DCB evidence is stronger for a defined recurrent bulbar population. Its broader FDA anterior-stricture label is not the same as the AUA selection recommendation. See the device companion for exact labeling, contraindications and contraception.[3][18][20]
  • HA/CMC and PRP remain investigational stricture adjuncts, rather than established substitutes when MMC cannot be used. A single small randomized study does not establish general clinical effectiveness or a preferred agent.[23][24][28]
  • FIRST-CARE is ongoing evidence development, not proof that DCB should replace initial standard treatment.[22]
  • The captopril tolerability signal concerns an intraluminal adjunct study; it is not a reason to discontinue indicated oral ACE-inhibitor therapy.[1]

See Also​

References​

1. Pang KH, Chapple CR, Chatters R, et al. "A systematic review and meta-analysis of adjuncts to minimally invasive treatment of urethral stricture in men." Eur Urol. 2021;80(4):467–479. doi:10.1016/j.eururo.2021.06.022

2. Jacobs ME, de Kemp VF, Albersen M, de Kort LMO, de Graaf P. "The use of local therapy in preventing urethral strictures: a systematic review." PLoS One. 2021;16(10):e0258256. doi:10.1371/journal.pone.0258256

3. Wessells H, Morey A, Souter L, Rahimi L, Vanni A. "Urethral stricture disease guideline amendment (2023)." J Urol. 2023;210(1):64–71. doi:10.1097/JU.0000000000003482

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5. Ayyildiz A, Nuhoglu B, Gülerkaya B, et al. "Effect of intraurethral mitomycin-C on healing and fibrosis in rats with experimentally induced urethral stricture." Int J Urol. 2004;11(12):1122–1126. doi:10.1111/j.1442-2042.2004.00959.x

6. Paz MM, Champeil E. "Insight into factors governing formation, synthesis and stereochemical configuration of DNA adducts formed by mitomycins." Chem Rec. 2023;23(1):e202200193. doi:10.1002/tcr.202200193

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11. Farrell MR, Sherer BA, Levine LA. "Visual internal urethrotomy with intralesional mitomycin C and short-term clean intermittent catheterization for the management of recurrent urethral strictures and bladder neck contractures." Urology. 2015;85(6):1494–1499. doi:10.1016/j.urology.2015.02.050

12. Vanni AJ, Zinman LN, Buckley JC. "Radial urethrotomy and intralesional mitomycin C for the management of recurrent bladder neck contractures." J Urol. 2011;186(1):156–160. doi:10.1016/j.juro.2011.03.019

13. Rozanski AT, Zhang LT, Holst DD, et al. "The effect of radiation therapy on the efficacy of internal urethrotomy with intralesional mitomycin C for recurrent vesicourethral anastomotic stenoses and bladder neck contractures: a multi-institutional experience." Urology. 2021;147:294–298. doi:10.1016/j.urology.2020.09.035

14. Sourial MW, Richard PO, Bettez M, Jundi M, Tu LM. "Mitomycin-C and urethral dilatation: a safe, effective, and minimally invasive procedure for recurrent vesicourethral anastomotic stenoses." Urol Oncol. 2017;35(12):672.e15–672.e19. doi:10.1016/j.urolonc.2017.07.031

15. Redshaw JD, Broghammer JA, Smith TG, et al. "Intralesional injection of mitomycin C at transurethral incision of bladder neck contracture may offer limited benefit: TURNS Study Group." J Urol. 2015;193(2):587–592. doi:10.1016/j.juro.2014.08.104

16. Klein R, Vasan R, Guercio C, Rusilko P. "Minimally invasive management of posterior urethral stricture / stenosis with DVIU and mitomycin C injection." Urology. 2024;183:e317–e319. doi:10.1016/j.urology.2023.10.006

17. Hao Z, Yu L. "Real-world safety profile of mitomycin: signal detection and time-to-onset analysis from FDA Adverse Event Reporting System and VigiAccess databases." Int J Clin Pharm. 2025. doi:10.1007/s11096-025-01994-0

18. Elliott SP, Coutinho K, Robertson KJ, et al. "One-year results for the ROBUST III randomized controlled trial evaluating the Optilume drug-coated balloon for anterior urethral strictures." J Urol. 2022;207(4):866–875. doi:10.1097/JU.0000000000002346

19. Kapriniotis K, Loufopoulos I, Apostolopoulou A, Anderson PCB, Papaefstathiou E. "Drug-coated balloon treatment for urethral strictures: is this the future? A review of the current literature." J Clin Med. 2025;14(8):2854. doi:10.3390/jcm14082854

20. Srikanth P, DeLong J, Virasoro R, Elliott SP. "A drug-coated balloon treatment for urethral stricture disease: three-year results from the ROBUST III study." J Endourol. 2025. doi:10.1089/end.2024.0718

21. Patel HV, Erickson BA, Abbasi B, et al. "Early real-world experience with Optilume drug-coated balloon for anterior urethral strictures and posterior urethral stenoses." Urology. 2025. doi:10.1016/j.urology.2025.10.025

22. Mahdi MB, Haase RN, Sander L, et al. "Treatment of bulbar urethral strictures with Optilume drug-coated balloons in a previously untreated population (FIRST-CARE): protocol for a single-blind multicentre randomised controlled trial." BMJ Open. 2026;16(1):e103948. doi:10.1136/bmjopen-2025-103948

23. Chung JH, Kang DH, Choi HY, et al. "The effects of hyaluronic acid and carboxymethylcellulose in preventing recurrence of urethral stricture after endoscopic internal urethrotomy: a multicenter, randomized controlled, single-blinded study." J Endourol. 2013;27(6):756–762. doi:10.1089/end.2012.0613

24. Chung JH, Kang DH, Moon HS, et al. "Effects of hyaluronic acid and carboxymethylcellulose on urethral stricture after transurethral resections of the prostate for benign prostatic hyperplasia: a multicenter, single-blinded, randomized controlled study." J Endourol. 2013;27(4):463–469. doi:10.1089/end.2012.0377

25. Kim SJ, Chae HK, Nam W, et al. "Patient satisfaction and feasibility with a novel drug-injectable urethral catheter set for hyaluronic acid administration: a multicenter randomized trial." Sci Rep. 2025;15(1):1575. doi:10.1038/s41598-024-84164-y

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27. Tavukcu HH, Aytaç Ö, Atuğ F, et al. "Protective effect of platelet-rich plasma on urethral injury model of male rats." Neurourol Urodyn. 2018;37(4):1286–1293. doi:10.1002/nau.23460

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29. Dellê H, Rocha JR, Cavaglieri RC, et al. "Antifibrotic effect of tamoxifen in a model of progressive renal disease." J Am Soc Nephrol. 2012;23(1):37–48. doi:10.1681/ASN.2011010046

30. Uyeturk U, Gucuk A, Firat T, et al. "Effect of mitomycin, bevacizumab, and 5-fluorouracil to inhibit urethral fibrosis in a rabbit model." J Endourol. 2014;28(11):1363–1367. doi:10.1089/end.2014.0420

31. Meng W, Jiang Z, Wang J, et al. "Inhibition of urethral stricture by a catheter loaded with nanoparticle/pirfenidone complexes." Front Bioeng Biotechnol. 2023;11:1254621. doi:10.3389/fbioe.2023.1254621

32. Choi KH, Kim DK, Kim AR, Lee SR. "Prevention of urethral fibrosis induced by transforming growth factor β1 using selective WNT/β-catenin signaling inhibitors in a rat model." Int J Urol. 2022;29(7):764–771. doi:10.1111/iju.14884

33. Zheng Z, Wu Z, Li C, et al. "Enhanced immunoregulation in traumatic urethral stricture repair utilizing a glycyrrhizic-acid-infused antiswelling biogel scaffold." RSC Adv. 2025;15(18):14217–14226. doi:10.1039/d5ra02083b

34. Tian J, Fu D, Liu Y, et al. "Rectifying disorder of extracellular matrix to suppress urethral stricture by protein-nanofilm-controlled drug delivery from urinary catheter." Nat Commun. 2023;14(1):2816. doi:10.1038/s41467-023-38282-2

35. Zhang K, Qi E, Zhang Y, Sa Y, Fu Q. "Efficacy and safety of local steroids for urethra strictures: a systematic review and meta-analysis." J Endourol. 2014;28(8):962–968. doi:10.1089/end.2014.0090

36. European Association of Urology. EAU Guidelines on Urethral Strictures: Disease Management in Males (2026), sections 6.2.3.b and 6.3.5.a.2.c. Guideline. Accessed September 12, 2026.