(E)-5-(2-Bromovinyl)-2'-Deoxyuridine in the Treatment of

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1 ANTIMICROBAL AGENTS AND CRE,OoTHERAPY, Jn. 980, P /80/0-0008/05$02.00/0 Vol. 7, No. (E)-5-(2-Bromovinyl)-2'-Deoxyuridine in the Tretment of Experimentl Herpes Simplex Kertitis P. C. MAUDGAL,' E. DE CLERCQ,2 J. DESCAMPS,2 L. MISSOTTEN,' P. DE SOMER,2 R. BUSSON,2 H. VANDERHAEGHE,2 G. VERHELST, R. T. WALKER, AND A. S. JONES Eye Reserch Lbortory, Ophthlmology Clinic, University of Leuven, B-000 Leuven, Belgium'; Reg Institute for Medicl Reserch, University of Leuven, B-000 Leuven, BelgiUM2; nd Deprtment of Chemistry, University ofbirminghm, Birminghm B5 2TT, Englnd" IDU (5-iodo-2'-deoxyuridine), BVDU [(E)-5-(2-bromovinyl)-2'-deoxyuridine], nd plcebo ointments were studied for their effects on experimentl herpes simplex (type ) kertoconjunctivitis in rbbits. When tretment ws begun 65 h fter virus inocultion, both BVDU nd IDU prevented development of kertitis. Both BVDU nd IDU were lso effective in suppressing the severity of conjuctivitis, nd in this respect, BVDU proved significntly better thn IDU. When tretment ws strted 0 h fter virus inocultion, BVDU proved significntly better thn IDU in promoting heling of estblished kertitis. Since its introduction in ophthlmologicl prctice in 962 (5), IDU (5-iodo-2'-deoxyuridine) hs remined the drug of choice in the tretment of herpes simplex kertitis (4). However, its toxicity, the emergence of IDU-resistnt virus strins, nd the inbility of IDU to prevent recurrences hve led to the serch for more effective nd less toxic ntiherpes gents. Of mny ntiherpes compounds developed so fr, only few drugs, i.e., r-a (9-fi-D-rbinofurnosyldenine) (9, ), phosphonocetic cid (8), TFT (trifluorothymidine or 5-trifluoromethyl- 2'-deoxyuridine) (6), nd cyclovir [cyclogunosine or 9-(2-hydroxyethoxymethyl)gunine] (4b, 7, 0) hve shown usefulness in the tretment of herpetic kertitis of nimls (rbbits) or humns or both. BVDU [(E)-5-(2-bromovinyl)-2'-deoxyuridine], newly synthesized thymidine nlog (2), hs been evluted by De Clercq et l. (, 2) for its potency nd selectivity s n ntiherpes gent in primry rbbit kidney nd humn skin fibroblst cell cultures. In these cell cultures BVDU ws bout 20 times more ctive ginst the repliction of herpes simplex virus (HSV) type (strin KOS) nd 60 times less toxic thn IDU s judged by inhibition of deoxyuridine incorportion into host cell deoxyribonucleic cid. BVDU surpssed vrious other estblished ntiherpes compounds, including phosphonocetic cid, TFT, r-a, r-t (-fl-d-rbinofurnosylthymine), nd cyclogunosine, in ctivity ginst HSV type in PRK cells. When pplied s % topicl ointment, BVDU ws bout s effective s cyclogunosine, phosphonocetic cid, nd trisodium phosphonoformte in preventing development of skin lesions in thymic nude mice inoculted intr- 8 cutneously with HSV type (strin KOS) (). Under the sme conditions, IDU effected but slight inhibition of vesicle formtion. When pplied s 0.% ointment, BVDU nd phosphonocetic cid, but not cyclogunosine, inhibited development of skin lesions. Once vesicles begn to pper (4 dys fter virus inocultion), neither phosphonocetic cid nor BVDU, pplied topiclly, suppressed evolution of the lesions. BVDU, however, effected reduction in the severity of the disese when dministered intrperitonelly (t dose of 60 mg/kg) (2). In this study we hve compred the effectiveness of BVDU nd IDU in preventing the evolution of experimentl herpes simplex kertoconjunctivitis in rbbits nd in treting the estblished disese. MATERIALS AND METHODS IDU ws obtined from Ludeco, Brussels. BVDU ws synthesized by procedures tht hve been published (4, ) or will be published shortly (R. Busson nd H. Vnderheghe, mnuscript in preprtion). The rbbits used in our experiments originted from cross breed of Clifornin lbino nd Dendermonde white rbbits. They were 2 weeks old, of both sexes, nd weighed.5 to 2 kg. In the first experiment 0 rbbits were infected t single setting in both eyes with HSV type (strin McIntyre). The eyelids were rubbed gently over the corne for 0 fter instilltion of one drop of the virus inoculum contining either 05 plgue-forming units (PFU) or 042 per ml. The nimls were divided into three s of 0 rbbits, ech contining 5 rbbits infected with the lower nd 5 with the higher virus dilution. Virus PFU were determined in Vero cell cultures. Tretment ws begun 65 h fter virus inocultion; ten nimls were treted with 0.5% IDU

2 VOL..7,980 ointment, ten nimls were treted with 0.5% BVDU ointment, nd the other ten nimls were treted with plcebo ointment [sterile eye ointment contining liquid prffin, yellow soft prffin, nd wool ft t 0: 80:0 (wt/wt/wt) rtio, ccording to Phrmcopoei (British) (2)]. The ointments were pplied five times dy t 2-h intervls during 5 consecutive dys. At ech ppliction, bout cm of ointment ws pressed out of n ophthlmic dispensing tube into the lower cul-de-sc of the eye. Rbbits were exmined dily on blind bsis by the sme individul. In the second experiment, nother 0 rbbits were infected t single setting in both eyes with HSV type (strin McIntyre). Only one virus dilution contining 052 PFU/ml ws employed in this study. Tretment ws strted 0 h fter virus inocultion. The ointments nd schedule nd durtion of therpy were the sme s in the first experiment. Clinicl evlutions were done by the sme exminer but not on blind bsis. Kertitis ws grded fter stining with 2% fluorescein solution by using 2x mgnifier. The severity of conjunctivitis ws scored from grde 0 to 4. Grde 0 ment no conjunctivitis, nd grde 4 ment mrked conjunctivitis with follicle formtion nd dischrge. Kertitis scores were s follows: grde 0, no kertitis; grde, one to five punctte lesions involving less thn / of the surfce of the corne; grde 2, one to five punctte lesions or smll ulcers involving up to / of the surfce of the corne; grde, six or more dendritic lesions or ulcers involving more thn / but less thn 2/ of the surfce of the corne; grde 4, dendritic lesions or smll ulcers involving more thn 2/ of the surfce of the corne but not the totl corne; grde 5, totl cornel ulcers. Sttisticl nlysis of the conjunctivitis nd kertitis scores between the IDU nd BVDU s ws BVDU EFFECT ON HERPES SIMPLEX KERATITIS 9 done by Student's t test. P vlues <0.05 were considered significnt. RESULTS AND DISCUSSION In our experiments both IDU nd BVDU, when pplied s 0.5% ointments, suppressed development of herpes simplex kertitis nd promoted heling of estblished kertitis nd conjunctivitis. -Among rbbits which hd been infected with 04.2 or 05.2 PFU of HSV per ml (experiment ), there ws no mrked difference in the severity of kertitis, neither t the time tretment ws strted nor lter on during the further evolution of the disese. Hence, for ll s (whether plcebo, IDU, or BVDU treted), the results were presented for the whole, irrespective of the virus inoculum dose (04.2 or 05.2 PFU/ ml). When tretment ws strted (65 h fter infection) most rbbits showed n erly stge of herpetic kertitis. The severity of kertitis stedily incresed in the plcebo, wheres IDU nd BVDU ointments suppressed the development of kertitis (Tble, Fig. ). Six rbbits of the BVDU hd grde kertitis on dy of tretment. The eyes grdully heled, so tht fter 5 dys of tretment only one eye showed mild grde kertitis. No new lesions ppered during the tretment period. Of the IDU, only one eye hd grde kertitis on dy of tretment. This eye grdully heled, but grde kertitis ppered in eight other eyes throughout the tretment period. Three of these eyes 'ra 0^nW;t;Q Q ADBLE i. LWerUtr&s scr ofbre lb;ere&n& est ex&er &n No. of eyes exhibiting grde lesions on Tretment Grde (dy fter strt of tretment): lesions BVDU None _ _ - IDU None Plcebo None : _, N.one.

3 0 MAUDGAL ET AL. heled, nd two deteriorted to totl cornel ulcers (grde 5 kertitis) in spite of the tretment. Three eyes showed grde kertitis t the end of the experiment. Although BVDU ppered cliniclly more effective thn IDU in suppressing the development of kertitis in this experiment (Tble, Fig. ), the difference ws not sttisticlly significnt (Fig. ). Both IDU nd BVDU cused rpid lessening of the conjunctivitis s compred to the plcebotreted (Tble 2, Fig. 2). The improvement ws evident within 48 h nd continued throughout the tretment period. BVDU ws significntly better thn IDU = (P 0.005) in suppressing conjunctivitis on dys 4 nd 5 of tretment (Fig. 2). The ltter observtion fur- 0 5 *- u ANTIMICROB. AGENTS CHEMOTHER. ther suggests tht BVDU by itself is nonirritting to the eye. In the second experiment the delyed pplictions of BVDU nd IDU promoted heling of the kertitis. Most nimls hd developed rther severe kertitis when tretment ws strted (0 h fter infection) (Tble, Fig. ). In the plcebo the severity of kertitis incresed progressively (conjunctivitis ws not scored in this experiment). In the IDU the existing lesions progressed before they begn to regress nd new lesions ppered during tretment. The heling effect of BVDU ws significntly better thn tht of IDU (P = 0.00 on dy 2 of tretment) (Fig. ). Throughout BVDU E._. c Plcebo o - z tnil..s5,r -_P._- ".IVD_ ~~~~~~~~D D y s Post Infection FIG. 2. Men (± stndrd error of the men) con- D ys Post I n f ec ti on junctivitis response curves by tretment. Tretment ws strted 65 h fter virus inocultion (corre- FIG.. Men (± stndrd error of the men) ker- sponds to dy 2.7 on the grph). S, Significnt; NS, titis response curves by tretment. Tretment not significnt. Significnce or lck of significnce ws st) rted 65 h fter virus inocultion (corresponds refers to the differences between the IDU nd BVDU to dy 2'. 7 on the grph). s. TABLE 2. Conjunctivitis scores of different eyes in experiment No. of eyes exhibiting grde conjunctivitis on Tretment Grde (dy fter strt of tretment): conjunctivitis BVDU None - _ IDU None Plcebo None None.

4 VOL. 7, 980 BVDU EFFECT ON HERPES SIMPLEX KERATITIS TABLE. Kertitis scores of different eyes in experiment 2 No. of eyes exhibiting grde lesions on Tretment Grde (dy fter strt of tretment): lesions BVDU None - _ _ - _ - IDU None Plcebo None None. O- 4~, 2k-... NC -, ebo Dys Post Infection FIG.. Men (± stndrd error of the men) kertitis response curves by tretment. Tretment ws strted I 0 h fter virus inocultion (corresponds to dy 4.5 on the grph). S, Significnt; NS, not significnt. Significnce or lck ofsignificnce refers to the differences between the IDU nd BVDU s. tretment the existing lesions grdully regressed nd no new lesions ppered. Although BVDU ppered better thn IDU throughout the whole tretment period, the difference in their effect becme progressively smller nd ws no longer sttisticlly significnt fter 5 dys of therpy (P = 0.05 on dy 4 nd P = 0.08 on dy 5 of tretment) (Fig. ). The difference on dy of tretment ws not significnt becuse of lrge stndrd error in scoring. We did not observe ny locl or generl untowrd side effects with the 0.5% BVDU eye ointment. Even when pplied s 2.5% ointment, BVDU did not produce ny toxicity to the eye, wheres both 2.5 nd 0.% BVDU ointments were found to be eqully effective s 0.5% BVDU ointment in treting herpetic kertitis (dt not shown). BVDU does not ffect the growth or metbolism of cultured cells, unless concentrtions re employed tht re 5,000- to 0,000-fold greter thn those required to inhibit virus multipliction (, 2). This implies tht BVDU is very selective in its ntiherpes ction. Apprent lck of toxicity of BVDU hs lso been demonstrted in thymic nude mice fter intrperitonel dministrtion of the drug t 600 mg/ kg (2). The exct mode of ction of BVDU nd the bsis for its selective ntiherpes ctivity re not yet known. However, its high ntiherpes ctivity, efficcy, nd pprent freedom from toxicity in vitro nd niml model systems, mkes it promising compound for the explortion of ntiherpes potentils in humns. ACKNOWVLEDG&MENTIS We thnk Fried De Meyer for excellent technicl ssistnce, P. Koninckx for help with the sttisticl nlysis of the dt, nd L. Cser (Apotheek A. Z. St. Rfel, Leuven) for preprtion of the ointments. This investigtion ws supported by grnts from the Belgin Fonds voor Geneeskundig Wetenschppelijk Onderzoek (Krediet ) nd the Geconcerteerde Onderzoekscties (Conventie 76/8-IV).

5 2 MAUDGAL ET AL LITERATURE CITED. De Clereq, E., J. Dscmps, P. J. BIw, A S. Jones, P. Serfinowski, R. T. Wlker, G. F. Hlng, P. F. Torrence, C. L. Schmidt, M. P. Mertes, T. Kulikowski, nd D. Shugr Comprtive study of the potency nd selectivity of nti-herpes compounds, p In J. Skod nd P. Lngen (ed.), Antimetbolites in biochemistry, biology nd medicine. Pergmon Press, Oxford. 2. De Clercq, E., J. Descmps, P. De Somer, P. J. Brr, A. S. Jones, nd R. T. Wlker (E)-5-(2-bromovinyl)-2'-deoxyuridine: potent nd selective ntiherpes gent. Proc. Ntl. Acd. Sci. U.S.A. 76: Descmps, J., E. De Clercq, P. J. Brr, A. S. Jones, R. T. Wlker, P. F. Torrence, nd D. Shugr Reltive potencies of different nti-herpes gents in the topicl tretment of cutneous herpes simplex virus infection of thymic nude mice. Antimicrob. Agents Chemother. 6: Guri, K. K. (ed.) Anti-herpevirus chemotherpy: experimentl nd clinicl spects. Adv. Ophthlmol. 8: Jones, A. S., G. Verhelst, nd R. T. Wlker The synthesis of the potent'nti-herpes virus gent, E- 5(2-bromovinyl)-2'-deoxyuridine nd relted compounds. Tetrhedron Lett. 45: b. Jones, B. R., D. J. Coster, P. N. Fison, S. M. Thompson, L il Cobo, nd AL G. Flcon Efficcy of cyclogunosine (Weilcome 248u) ginst herpes-simplex cornel ulcers. Lncet i: ANTIMICROB. AGENTS CHEMOTHER. 5. Kufmn, EL E Clinicl cure of herpes simplex kertitis bys-iodo-2'-deoxyuridine. Proc. Soc. Exp. Biol. Med. 09: Kufmn, H. E., nd C. Heidelberger Therpeutic ntivirl ction of 5-trifluoromethyl-2'-deoxyuridine. Science 45: Kufmn, H. E., E. D. Vrnell, Y. M. Centifnto, nd S. D. Rheinstrom Effect of 9-(2-hydroxyethoxymethyl)gunine on herpevirsinduced kertiti nd irtis in rbbits. Antimicrob. Agents Chemother. 4: Meyer, R. F., E. D. Vrnell, nd H. E. Kufmn Phosphonocetic cid in the tretment of experimentl oculr herpes simplex infections. Antimicrob. Agents Chemother. 9: Pvn-Lngston, D., R. A. Buchnn, nd C. A. AMfbrd, Jr. (ed.) Adenine rbinoside: n ntivirl gent. Rven Press, New York. 0. Pvn-Lngton, D., R. Cmpbell, nd J. Iss Acyclic ntimetbolite therpy of experimentl herpes simplex kertitis. Am. J. Ophthlmol. 86: Pvn-Lngston, D., nd C. H. Dohlmn A double-blind clinicl study of denine rbinoside therpy of virl kertoconjunctivitis. Am. J. Ophthlmol. 74: Phrmcopoei (British) Her Mjesty's Sttionery Office, London.. Wlker, R. T., P. J. Brr, E. De Clercq, J. DeNcmps, A. S. Jones, nd P. Serfinowdi The synthesis nd properties ofsome ntivirl nucleosides. -Nucleic Acids Res. 4 (Specil Publiction):sl0-sl06.