Drug
Acyclovir clinical trials
Also written Zovirax and Aciclovir.
Includes 87 studies of Valacyclovir.
How each study uses Acyclovir is sorted by a rule, right about nine times in ten. Readers can ask us to read every study one by one.Ask us to read each study
Get an email when these change. Save the Acyclovir studies recruiting or about to start — once a week, free: studies that open, close, add sites or post results.
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Breast cancer · Recruiting: 2 came in, 3 changed
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A study of drug A after surgery for early breast cancer
Came in · now Recruiting
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Changed
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Approvals
The first approval found in each region, with its record
- United States
- 29 Mar 1982 · ZOVIRAX · NDA 018604 (FDA, Drugs@FDA)
- European Union
- Not in EMA's list of EU-wide authorisations
From FDA's Drugs@FDA and Purple Book (through openFDA) and the European Medicines Agency, files of Sept 2026 and 27 Oct 2026. National approvals in Europe and other countries are not included. How this is worked out
How studies write it
Studies that test it under each name
Studies by the year they started
127 studies that test it; most in 2005 (12); 1 more planned to start later
| Year | Studies |
|---|---|
| 1992 | 2 |
| 1995 | 1 |
| 1997 | 5 |
| 1998 | 1 |
| 1999 | 2 |
| 2000 | 1 |
| 2001 | 2 |
| 2002 | 1 |
| 2003 | 5 |
| 2004 | 7 |
| 2005 | 12 |
| 2006 | 7 |
| 2007 | 6 |
| 2008 | 6 |
| 2009 | 7 |
| 2010 | 6 |
| 2011 | 4 |
| 2012 | 4 |
| 2013 | 3 |
| 2014 | 4 |
| 2015 | 3 |
| 2016 | 2 |
| 2017 | 5 |
| 2018 | 3 |
| 2019 | 3 |
| 2020 | 2 |
| 2021 | 4 |
| 2022 | 3 |
| 2023 | 4 |
| 2024 | 7 |
| 2025 | 2 |
| 2026 | 3 |
By phase
A phase 1/2 study counts in both.
What it is tested for
Each study’s main condition, where its own words name it, so a study counts once.
Who runs them
Industry 36 · Other 109
National Institute of Allergy and Infectious Diseases (NIAID) (16) · University of Washington (13) · Glaxo Wellcome (7) · GlaxoSmithKline (6) · National Center for Research Resources (NCRR) (5) · Mylan Pharmaceuticals Inc (3) · Radboud University Medical Center (3) · Fred Hutchinson Cancer Center (3)
Often tested with
Tested in the same studies.
Ganciclovir (4) · Zidovudine (4) · Aglatimagene besadenovec (2) · Methylprednisolone (2) · Alemtuzumab (2) · Acetaminophen (2) · Cetirizine (2) · Dexchlorpheniramine (2)
Coming up
From the study records. Dates are the sponsors’ own estimates and often move.
Tested against it · 1 phase 3 study under way
Acyclovir is the comparator. A study of two new drugs counts under both.
- 1Letermovir · Assistance Publique - Hôpitaux de Paris · next primary completion Aug 2029
Reaching primary completion within a year · 5
Studies that test Acyclovir.
- Dec 2026Individualization of Dosage Regimens in Obese Patients: Application to AcyclovirPhase 1 · University Hospital, Toulouse
- Feb 2027A Biomarker Study in Men With Localized Prostate Cancer Treated With Aglatimagene BesadenovecPhase 2 · Candel Therapeutics, Inc.
- Mar 2027Preemptive Treatment With Acyclovir in Intubated and Mechanically Ventilated Patients With Herpes (PTH2)Not applicable · Assistance Publique - Hôpitaux de Paris
- Apr 2027Prevention of Recurrence of Herpes Simplex in Autoimmune Rheumatic DiseasesPhase 4 · University of Sao Paulo General Hospital
- Aug 2027VZV in the Enteric Nervous System: Pathogenesis and ConsequencesPhase 4 · Vanderbilt University Medical Center
Studies
Open first, then newest update. How each study uses Acyclovir is read from its arms, and is right about nine times in ten. Ask us to read each study. These are the studies that list it as an intervention; a search of ClinicalTrials.gov also finds studies that mention it only in a description, such as earlier treatment.
Testing it · 145
- Aciclovir Versus Placebo for HSV-2 MeningitisNot yet recruitingPhase 4Jacob BodilsenNCT05452928Written as Acyclovir 50 MG/ML
- SARS-CoV-2 and Herpesvirus Inhibition for Ending Long COVID DysfunctionRecruitingPhase 2Icahn School of Medicine at Mount SinaiNCT07597902Written as Valacyclovir
- VZV in the Enteric Nervous System: Pathogenesis and ConsequencesRecruitingPhase 4Vanderbilt University Medical CenterNCT05550194Written as ValACYclovir 1000 MG
- A Biomarker Study in Men With Localized Prostate Cancer Treated With Aglatimagene BesadenovecRecruitingPhase 2Candel Therapeutics, Inc.NCT07332000Written as aglatimagene besadenovec + valacyclovir
- Prevention of Recurrence of Herpes Simplex in Autoimmune Rheumatic DiseasesRecruitingPhase 4University of Sao Paulo General HospitalNCT07341386Written as Acyclovir (ACV)
- Acyclovir in Ventilated Patients With Pneumonia and HSV-1 in BALRecruitingPhase 3Jena University HospitalNCT06134492Written as Acyclovir
- Virus-Based Gene Therapy (AdV-HSV1-TK and AdV-Flt3L) in Combination With Valacyclovir for the Treatment of Pediatric and Young Adult Patients With Resectable, Recurrent Primary Malignant Brain TumorsRecruitingPhase 1University of Michigan Rogel Cancer CenterNCT06914479Written as Valacyclovir
- Oral Herpesviruses and Oral Mucositis in Patients Receiving Head and Neck RadiotherapyEnrolling by invitationPhase 2Instituto OncoclinicasNCT07363031Written as Valacyclovir
- Individualization of Dosage Regimens in Obese Patients: Application to AcyclovirRecruitingPhase 1University Hospital, ToulouseNCT05589688Written as Acyclovir
- Is Valacyclovir Non-inferior to Valganciclovir as CMV and EBV Prophylaxis in Kidney Transplant Recipients? A Single-Center Prospective Randomized Pilot StudyRecruitingNot applicableNational Taiwan University HospitalNCT07294547Written as Valacyclovir (Valtrex)
- Valacyclovir in Pain Management of Acute Apical AbscessesRecruitingPhase 2University of California, San FranciscoNCT05266040Written as Valacyclovir 500 MG
- Valacyclovir Monotherapy in Pain Management of Acute Periapical Abscesses After Emergency Chamber OpeningRecruitingPhase 4Dow University of Health SciencesNCT06344195Written as Valacyclovir 500 mg
- The Bioequivalence Study of Acyclovir 800 mg Tablet in Healthy Thai Volunteers Under Fasting ConditionsNot yet recruitingPhase 1International Bio serviceNCT06228430Written as Acyclovir 800 mg Tablet
- Preemptive Treatment With Acyclovir in Intubated and Mechanically Ventilated Patients With Herpes (PTH2)Not yet recruitingNot applicableAssistance Publique - Hôpitaux de ParisNCT06217406Written as Intravenous acyclovir (ACYCLOVIR )
- The Efficacy of Systemic Valacyclovir (Valtrex) on PeriodontitisRecruitingEarly Phase 1University of California, San FranciscoNCT05712343Written as Valacyclovir group
- A Study to Evaluate Efficacy, Safety, and Tolerability of Alemtuzumab in Pediatric Patients With RRMS With Disease Activity on Prior DMTTerminatedPhase 3Genzyme, a Sanofi CompanyNCT03368664Written as Acyclovir
- Neonatal Phase 1 Valacyclovir StudyCompletedPhase 1National Institute of Allergy and Infectious Diseases (NIAID)NCT05468619Written as Valacyclovir
- Valacyclovir for Mild Cognitive ImpairmentCompletedPhase 2New York State Psychiatric InstituteNCT04710030Written as Valacyclovir hydrochloride 500mg caplet
- Anti-viral Therapy in Alzheimer's DiseaseCompletedPhase 2Columbia UniversityNCT03282916Written as Valacyclovir
- A Study to Compare Sitavig (Acyclovir) Buccal Tablet With a Placebo in the Treatment of Herpes Labialis in Participants Whose Immune System Works NormallyCompletedPhase 3BayerNCT05098938Written as Acyclovir 50mg buccal/topical tablet, BAYM008894/UI1614773
See all 145 studies that test Acyclovir →
Given beside what is tested · 31 — Acyclovir is usual care or a partner of the new treatment
- Study of an AAV Mediated Dual-Payload Gene Therapy in Patients With High Grade GliomaRecruitingPhase 1/2Trogenix ltdNCT07346144Written as Valaciclovir
- A Study of the Safety and Tolerability of ASP7317 in Senior Adults Who Are Losing Their Clear, Sharp Central Vision Due to Geographic Atrophy Secondary to Dry Age-related Macular DegenerationRecruitingPhase 1Astellas Institute for Regenerative MedicineNCT03178149Written as Acyclovir
- Aglatimagene Besadenovec + Prodrug and Pembrolizumab vs Docetaxel for Stage IV Non-Squamous NSCLC Progressing on Pembrolizumab (AURORA)RecruitingPhase 3Candel Therapeutics, Inc.NCT07660094Written as Valacyclovir
- Efficacy of Electroacupuncture for Acute Herpes Zoster-Associated Pain and Biomarker EvaluationRecruitingNot applicableDexiong HanNCT07515885Written as Valacyclovir, pregabalin and mecobalamin
- Time-limited Triplet Combination of Pirtobrutinib, Venetoclax, and Obinutuzumab for Patients With Treatment-naïve Chronic Lymphocytic Leukemia (CLL) or Richter Transformation (RT)RecruitingPhase 2M.D. Anderson Cancer CenterNCT05536349Written as Valacyclovir
- CAN-2409 Plus Prodrug With Standard of Care Immune Checkpoint Inhibitor for Stage III/IV NSCLCActive, not recruitingPhase 2Candel Therapeutics, Inc.NCT04495153Written as Valacyclovir
- Phase 3 Study of ProstAtak® Immunotherapy With Standard Radiation Therapy for Localized Prostate CancerActive, not recruitingPhase 3Candel Therapeutics, Inc.NCT01436968Written as Aglatimagene besadenovec + valacyclovir
- Randomized Controlled Trial of CAN-2409 Immunotherapy During Active Surveillance for Prostate Cancer (ULYSSES)Active, not recruitingPhase 2Candel Therapeutics, Inc.NCT02768363Written as valacyclovir
- Bortezomib and Rituximab for Patients With Waldenstrom's MacroglobulinemiaActive, not recruitingPhase 2M.D. Anderson Cancer CenterNCT00492050Written as Valacyclovir
- GMCI, Nivolumab, and Radiation Therapy in Treating Patients with Newly Diagnosed High-Grade GliomasCompletedPhase 1Candel Therapeutics, Inc.NCT03576612Written as Valacyclovir
- Carfilzomib, Rituximab, and Combination Chemotherapy in Treating Patients With Diffuse Large B-Cell LymphomaCompletedPhase 1/2Case Comprehensive Cancer CenterNCT02073097Written as Acyclovir
- Phase 2a Study of CAN-2409 With Standard Radiation Therapy for Malignant GliomaCompletedPhase 2Candel Therapeutics, Inc.NCT00589875Written as Valacyclovir
- Trial of Radiation and Gene Therapy Before Nivolumab for Metastatic Non-Small Cell Lung Carcinoma and Uveal MelanomaTerminatedPhase 2Eric Bernicker, MDNCT02831933Written as Valacyclovir
- A Phase I Study of AdV-tk + Prodrug Therapy in Combination With Radiation Therapy for Pediatric Brain TumorsCompletedPhase 1Candel Therapeutics, Inc.NCT00634231Written as valacyclovir
- AdV-tk Therapy With Surgery and Chemoradiation for Pancreas Cancer (PaTK01)CompletedPhase 1Candel Therapeutics, Inc.NCT00638612Written as Valacyclovir
- Phase 1b Study of AdV-tk + Valacyclovir Combined With Radiation Therapy for Malignant GliomasCompletedPhase 1Candel Therapeutics, Inc.NCT00751270Written as Valacyclovir
- Intrapleural AdV-tk Therapy in Patients With Malignant Pleural EffusionCompletedPhase 1Candel Therapeutics, Inc.NCT01997190Written as AdV-tk + valacyclovir
- Letermovir Versus Valganciclovir to Prevent Human Cytomegalovirus Disease in Kidney Transplant Recipients (MK-8228-002)CompletedPhase 3Merck Sharp & Dohme LLCNCT03443869Written as Acyclovir (ACV)
- Safety and Efficacy Comparator Trial of a New Drug Against Genital HerpesTerminatedPhase 2AiCuris Anti-infective Cures AGNCT01658826Written as Valacyclovir
- Alemtuzumab and Combination Chemotherapy in Treating Patients With Untreated Acute Lymphoblastic LeukemiaCompletedPhase 1/2National Cancer Institute (NCI)NCT00061945Written as acyclovir
Showing 20 of 31.
As the comparator · 18 — what is tested is compared with Acyclovir
- Study to Compare GS-1179 Versus Valacyclovir in HSV-2 Seropositive Participants With Recurrent Genital HerpesNot yet recruitingPhase 2Gilead SciencesNCT07912996Written as Valacyclovir
- Prenatal Treatment of Congenital Cytomegalovirus Infection With Letermovir Versus ValaciclovirRecruitingPhase 3Assistance Publique - Hôpitaux de ParisNCT05446571Written as Valacyclovir
- A Study Exploring Efficacy of Peginterferon in Patients With Herpes ZosterCompletedPhase 2Shanghai Institute Of Biological ProductsNCT05492591Written as Valacyclovir
- Monoclonal Antibody Therapy Against Chronic Herpes Simplex Virus 2 InfectionCompletedPhase 2Heidelberg ImmunoTherapeutics GmbHNCT04165122Written as Valaciclovir
- Trial on Efficacy and Safety of Pritelivir Ointment for Treatment of Labial HerpesCompletedPhase 2AiCuris Anti-infective Cures AGNCT02871492Written as Zovirax® cream
- Efficacy and Safety of Foscarnet Sodium and Sodium Chloride Injection in Patients With Herpes ZosterCompletedPhase 4CttqNCT02151240Written as Acyclovir
- Efficacy of Oral Famciclovir 125mg Comparing to Aciclovir 200 mg Treatment in Patients With Active Recurrent Genital HerpesCompletedPhase 3EMSNCT01281007Written as Aciclovir
- Safety, Tolerability and Therapeutic Efficacy of Topical ZEP-3 Ointment (1.0%) for the Treatment of Cold SoresCompletedPhase 2Shulov Innovate for Science Ltd. 2012NCT02483182Written as Acyclovir cream 5%
- Efficacy of Oral Famciclovir Versus Aciclovir Treatment in Patients With Herpes ZosterCompletedPhase 3EMSNCT01327144Written as Aciclovir
- Dose-finding Study of ASP2151 in Subjects With Herpes ZosterCompletedPhase 2Astellas Pharma IncNCT00487682Written as Valacyclovir hydrochloride
- A Comparative Study of FV-100 vs. Valacyclovir for the Prevention of Post-Herpetic NeuralgiaTerminatedPhase 3ContraVir Pharmaceuticals, Inc.NCT02412917Written as valacyclovir
- A Study With ASP2151 in Subjects With Recurrent Episodes of Genital HerpesCompletedPhase 2Astellas Pharma IncNCT00486200Written as valacyclovir
- A Study of FV-100 Versus Valacyclovir in Patients With Herpes ZosterCompletedPhase 2Bristol-Myers SquibbNCT00900783Written as valacyclovir
- Valganciclovir in Prevention of Cytomegalovirus (CMV) Reactivation Following Allogeneic-Stem Cell Transplantation (SCT)CompletedPhase 3Hadassah Medical OrganizationNCT00330018Written as Acyclovir
- A Phase 2b Trial of EPB-348 for the Treatment of Herpes ZosterCompletedPhase 2Epiphany BiosciencesNCT00831103Written as Valacyclovir
- Non-inferiority Comparison of Efficacy and Safety of Penciclovir 10mg/g to Acyclovir 50mg/g in the Treatment of Recurrent Herpes LabialisCompletedPhase 3EMSNCT01257074Written as Acyclovir 50mg/g
- Study Comparing the Safety of ASP2151 to Valacyclovir and Placebo in Healthy VolunteersTerminatedPhase 1Astellas Pharma IncNCT00870441Written as Valacyclovir
- Efficacy and Safety of Famciclovir 1-day Treatment Compared to 3-day Treatment With Valacyclovir in Adults With Recurrent Genital HerpesCompletedPhase 3Novartis PharmaceuticalsNCT00306787Written as Valacyclovir
What changed recently
From the registry's own updates since Oct 15, 2026.
Started recruiting1
- SARS-CoV-2 and Herpesvirus Inhibition for Ending Long COVID DysfunctionOct 28, 2026NCT07597902
Codes
What other systems call Acyclovir · ClinicalTrials.gg INT006901
- MeSH (NLM) D000212AcyclovirConfirmed ClinicalTrials.gov, NLM
- UNII (FDA) X4HES1O11FACYCLOVIRConfirmed FDA, NLM
- RxNorm 281One source FDA
- NCI Thesaurus C205AcyclovirOne source FDA
| System | Code | Name there | Checked by |
|---|---|---|---|
| MeSH (NLM) | D000212 | Acyclovir | Confirmed ClinicalTrials.gov, NLM |
| UNII (FDA) | X4HES1O11F | ACYCLOVIR | Confirmed FDA, NLM |
| RxNorm | 281 | — | One source FDA |
| NCI Thesaurus | C205 | Acyclovir | One source FDA |
Also registered as acyclovir sodium (UNII 927L42J563 · RxNorm 81944).
“Confirmed” means two independent publishers link the code to this drug; “one source”, one does and its name agrees.