Drug information

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Pronounce:
Other Names
mAb dB4, mAb dB4C7, Semzuvolimab
Drug Class
CD4 Attachment Inhibitor
Registry Number
1888475-19-1 (CAS)
Organization
United Biomedical
Phase of Development

UB-421 is in Phase 3 development for HIV treatment.

(Compound details obtained from ChemIDplus Advanced,1ClinicalTrials.gov,2 and Treatment Action Group Pipeline Report 20213

 
What is UB-421?What is UB-421?

What is UB-421?

UB-421 is an investigational drug that is being studied to treat HIV infection.3

UB-421 belongs to a group of HIV drugs called CD4 attachment inhibitors.3 CD4 attachment inhibitors work by attaching to a protein on the surface of the immune cells. The protein is called the CD4 receptor. When UB-421 attaches to the CD4 receptor, HIV cannot attach to, enter, or infect the cell.4 This prevents HIV from multiplying and can reduce the amount of HIV in the body.

To learn about how investigational drugs are tested during clinical trials, read the HIVinfo What is an Investigational HIV Drug? and HIV and AIDS Clinical Trials fact sheets.

Select clinical trials of UB-421Select clinical trials of UB-421

Select clinical trials of UB-421

Study Name: NCT01668043 
Phase: 2a
Status: This study has been completed.
Location: Taiwan
Purpose: The purpose of this study was to look at two different doses of UB-421 monotherapy in adults with HIV who had never taken HIV medicines before. UB-421’s safety and effectiveness in lowering viral load were assessed.5

Study Name: NCT02369146 
Phase: 2
Status: This study has been completed.
Location: Taiwan
Purpose: The purpose of this study was to evaluate the safety and effectiveness of two different doses of UB-421 monotherapy as a substitute for antiretroviral therapy (ART).6
Selected Study Results: Results presented at CROI 2017 and published in the New England Journal of Medicine showed that treatment with UB-421 monotherapy in participants with viral suppression was safe and effective in preventing viral rebound during a structured treatment interruption of ART.7,8

Study Name: NCT03743376
Phase: 2
Status: This study is ongoing, but not recruiting participants.
Location: Taiwan
Purpose: The purpose of this study is to evaluate the safety and effectiveness of UB-421 when used in combination with ART.9

Study Name: NCT03164447
Phase: 2
Status: See the ClinicalTrials.gov record for this study’s status.
Location: Not available.
Purpose: The purpose of this study is to evaluate the efficacy, safety, and tolerability of UB-421 when used first with an ART regimen that is not working, then with optimized background therapy (OBT).10

Study Name: NCT04985890
Phase: 2
Status: See the ClinicalTrials.gov record for this study’s status. 
Location: Not available.
Purpose: The purpose of this study is to evaluate the safety of UB-421 plus the latency-reversing agent tucidinostat and the ability of this regimen in reducing the latent HIV reservoir in participants undergoing a structured treatment interruption of ART.11

Study Name: NCT04404049 
Phase
: 2
Status: See the ClinicalTrials.gov record for this study’s status.
Location: Not available.
Study Purpose: The purpose of this study is to evaluate the safety of UB-421 and its effectiveness in reducing the latent HIV reservoir when used in combination with ART.12

Study Name: NCT03149211 
Phase: 3
Status: See the ClinicalTrials.gov record for this study’s status. 
Location: Not available.
Purpose: The purpose of this study is to evaluate the safety and effectiveness of UB-421 monotherapy as a substitute for ART.2

Study Name: NCT04406727 
Phase: 3
Status: See the ClinicalTrials.gov record for this study’s status.  
Location: Not available.
Study Purpose: The purpose of this study is to evaluate the effectiveness of UB-421 plus optimized background therapy in reducing viral load levels in participants with multidrug-resistant HIV.13

For more details on the studies listed above, see the Health Professional version of this drug summary.

What side effects might UB-421 cause?What side effects might UB-421 cause?

What side effects might UB-421 cause?

One goal of HIV research is to identify new drugs that have fewer side effects. In one of the Phase 2 studies (NCT02369146) discussed under the previous section, the most common side effect that was possibly or probably related to UB-421 was mild or moderate skin rash, and it occurred in about 48% of participants. One participant discontinued UB-421 because of a rash. Some participants had increases in eosinophils, which are a type of disease-fighting white blood cell, and some participants had elevated liver enzyme levels.7,8

Because UB-421 is still being studied, information on possible side effects of the drug is not complete. As testing of UB-421 continues, additional information on possible side effects will be gathered.

Where can I get more information about clinical trials studying UB-421?Where can I get more information about clinical trials studying UB-421?

Where can I get more information about clinical trials studying UB-421?

More information about UB-421-related research studies is available from ClinicalTrials.gov.

Some clinical trials may be looking for volunteer participants. Your health care provider can help you decide whether participating in a clinical trial is right for you. For more information, visit NIH Clinical Research Trials and You.

ReferencesReferences

References

  1. United States National Library of Medicine. ChemIDplus Advanced: UB-421. https://chem.nlm.nih.gov/chemidplus/rn/1888475-19-1. Accessed November 3, 2021
  2. United BioPharma. A Phase III, randomized, open-label, controlled trial to investigate the efficacy and safety of UB-421 monotherapy as substitution for stable antiretroviral therapy in HIV-1 infected adults. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on May 2, 2017. NLM Identifier: NCT03149211. https://clinicaltrials.gov/ct2/show/NCT03149211. Accessed November 3, 2021
  3. Jefferys R. The antiretroviral therapy pipeline 2021. Treatment Action Group Pipeline Report 2021. https://www.treatmentactiongroup.org/wp-content/uploads/2021/07/pipeline_2021_hiv_ARV_final.pdf. Accessed November 3, 2021
  4. United BioPharma website. Pipeline. http://www.unitedbiopharma.com/pipelines.php. Accessed November 3, 2021
  5. United Biomedical. A Phase IIa, open-label, multiple-dose trial to investigate the safety and efficacy of the UB-421 in asymptomatic HIV-1 infected adults. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on August 1, 2012. NLM Identifier: NCT01668043. https://clinicaltrials.gov/ct2/show/NCT01668043. Accessed November 3, 2021
  6. United BioPharma. A Phase II, open-label, multiple-dose trial to investigate the safety and efficacy of UB-421 monotherapy in substitution for stable antiretroviral therapy in HIV infected adults. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on February 5, 2015. NLM Identifier: NCT02369146. https://clinicaltrials.gov/ct2/show/NCT02369146. Accessed November 3, 2021
  7. Wang CY, Wong WW, Tsai HC, Chen YH, Liao MJ, Lynn S. A Phase 2 Open-Label Trial of Antibody UB-421 Monotherapy as a Substitute for HAART. Poster presented at: Conference on Retroviruses and Opportunistic Infections (CROI); February 13-16, 2017; Seattle, WA. Poster 450LB. https://2jg4quetidw2blbbq2ixwziw-wpengine.netdna-ssl.com/wp-content/uploads/sites/2/posters/2017/450LB_Wong.pdf. Accessed November 3, 2021
  8. Wang CY, Wong WW, Tsai HC, et al. Effect of anti-CD4 antibody UB-421 on HIV-1 rebound after treatment interruption. N Engl J Med. 2019;380(16):1535-1545. doi:10.1056/NEJMoa1802264
  9. United BioPharma. The HIV functional cure potential of UB-421: a Phase II, randomized, open-label, controlled, 48 week, proof of concept study, to evaluate the safety of UB-421 in combination with standard antiretroviral therapy (ART) and the efficacy of HIV reservoir reduction as compared with ART alone in ART stabilized HIV-1 patients. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on November 12, 2018. NLM Identifier: NCT03743376. https://clinicaltrials.gov/ct2/show/NCT03743376. Accessed November 3, 2021
  10. United BioPharma. A multicenter, single-arm, 24-week study of UB-421 in combination with optimized background therapy (OBT) regimen in patients with multi-drug resistant (MDR) HIV-1 infection.  In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on May 21, 2017. NLM Identifier: NCT03164447. https://clinicaltrials.gov/ct2/show/NCT03164447. Accessed November 3, 2021
  11. UBP Greater China (Shanghai) Co., Ltd. A proof of concept study to evaluate the safety and efficacy of UB-421 in combination with Chidamide for reduction of HIV reservoir as compared to UB-421 alone in ART stabilized HIV-1 patients who undergo ART interruption.  In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on July 8, 2021. NLM Identifier: NCT04985890. https://clinicaltrials.gov/ct2/show/NCT04985890. Accessed November 3, 2021
  12. UBP Greater China (Shanghai) Co., Ltd. The HIV functional cure potential of UB-421: a Phase II, randomized, open-label, controlled, 48 week, proof of concept study, to evaluate the safety of UB-421 in combination with standard antiretroviral therapy (ART) and the efficacy of HIV reservoir reduction as compared with ART alone in ART stabilized HIV-1 patients.  In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on May 21, 2020. NLM Identifier: NCT04404049. https://clinicaltrials.gov/ct2/show/NCT04404049. Accessed November 3, 2021
  13. United BioPharma. A randomized, double-blind, placebo-controlled Phase 3 trial with UB-421 in combination with optimized background regimen in patients with multi-drug resistant HIV-1 infection. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on May 22, 2020. NLM Identifier: NCT04406727. https://clinicaltrials.gov/ct2/show/NCT04406727. Accessed November 3, 2021
 

Last Reviewed: November 3, 2021