Semzuvolimab (UB-421)

Associated long-acting platforms

Monoclonal antibodies and antibody drug conjugates

Administration route

Subcutaneous, Intravenous

Therapeutic area(s)

Use case(s)

Use of drug

Dosage

Drug information

Delivery device(s)

No delivery device

Scale-up prospects

Not reported for this product. Generic monoclonal antibody scale-up considerations apply: formulation stability, maintenance of critical quality attributes, and the higher concentrations needed for a subcutaneous presentation.

Tentative equipment list for manufacturing

Not reported for this product. Standard therapeutic mAb train assumed: production bioreactors, continuous disc-stack centrifugation and depth/membrane filtration for harvest clarification, Protein A and polishing chromatography, viral inactivation and filtration, ultrafiltration/diafiltration, sterile fill-finish.

Manufacturing

Recombinant humanised IgG1 produced in mammalian cell culture; aglycosylated Fc. Detailed cell line, process and facility information has not been published.

Specific analytical instrument required for characterization of formulation

Not reported for this product. Standard mAb characterisation applies: ion-exchange chromatography and capillary isoelectric focusing for charge variants, size-exclusion chromatography for aggregates, DSC for thermal stability, subvisible particle counting, and binding/potency assays (CD4 receptor occupancy by flow cytometry).

UBP-A202-HIV

Identifier

NCT02369146

Link

https://clinicaltrials.gov/study/NCT02369146

Phase

Phase II

Status

Completed

Sponsor

United BioPharma

More details

The purpose of this phase II study is to evaluate the safety, tolerability and efficacy of two multi-dose regimens of UB-421 monotherapy in replacement of HAART in HIV-1 infected adults with virological suppression.

Purpose

To Investigate the Safety and Efficacy of UB-421 Monotherapy in HIV Infected Adults

Interventions

Intervention 1

Intervention 2

Countries

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
Not provided

Actual Start Date
2015-06-01

Anticipated Date of Last Follow-up
2017-10-29

Estimated Primary Completion Date
Not provided

Estimated Completion Date
Not provided

Actual Primary Completion Date
2016-07-01

Actual Completion Date
2016-07-01

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

Inclusion Criteria: * HIV-1 sero-positive * Aged 20 years or older * Have received HAART treatment * CD4+ T cell count ≧ 350 cells/mm3 * HIV-1 plasma RNA level remains below the limit of * Were not breastfeeding for women * Subjects with a negative serum pregnancy test result at screening visit for women of childbearing potential * Subjects agree on using birth control barrier (female or male condom) during the entire study period * Subjects sign the informed consent before undergoing any study procedures Exclusion Criteria: * Any active infection except for HIV, and required immediate therapy * Any active AIDS-defining illness per Category B and Category C conditions according to the U.S. Centers for Disease Control and Prevention (CDC) Classification System for HIV Infection * Any doc

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

29

Allocation

Not provided

Intervention model

Parallel Assignment

Intervention model description

Not provided

Masking

Open label

Masking description

Not provided

Frequency of administration

Studied LA-formulation(s)

Studied route(s) of administration

Use case

Treatment

Key resources

UBP-A209-HIV

Identifier

NCT03743376

Link

https://clinicaltrials.gov/study/NCT03743376

Phase

Phase II

Status

Completed

Sponsor

United BioPharma

More details

UBP-A202-HIV - monotherapy substitution for stable ART. This study evaluates 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

Purpose

The HIV Functional Cure Potential of UB-421 in ART Stabilized HIV-1 Patients

Interventions

Intervention 1

Intervention 2

Countries

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
Not provided

Actual Start Date
2018-12-12

Anticipated Date of Last Follow-up
2022-05-12

Estimated Primary Completion Date
Not provided

Estimated Completion Date
Not provided

Actual Primary Completion Date
2020-10-15

Actual Completion Date
2021-12-31

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

Inclusion Criteria: 1. HIV-1 sero-positive 2. Male with body weight ≥ 50 kg or female with body weight ≥ 45 kg. 3. HIV-1 plasma RNA level below 50 RNA copies/mL . Exclusion Criteria: 1. Subjects with active systemic infections, except for HIV-1, that the Investigator feels the infections may confound evaluation and treatment for HIV-1. 2. Current active hepatitis B carriers, ie, hepatitis B surface antigen positive. 3. Current active hepatitis C carriers, ie, hepatitis C virus (HCV) antibody positive. 4. History of anaphylaxis to other mAbs. 5. Any vaccination within 8 weeks prior to the first dose of assigned drug. 6. Use of immunomodulators, HIV vaccine, or systemic chemotherapy within 180 days prior to the first dose of assigned drug. 7. Females who are pregnant, lactating, or breast

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

31

Allocation

Randomized

Intervention model

Parallel Assignment

Intervention model description

Open-label, non-randomised, multiple-dose study in 29 virologically suppressed adults undergoing analytical treatment interruption. Cohort 1: 10 mg/kg IV weekly (8 doses). Cohort 2: 25 mg/kg IV every 2 weeks (8 doses).

Masking

Open label

Masking description

Not provided

Frequency of administration

Studied LA-formulation(s)

Studied route(s) of administration

Use case

Treatment

Key resources

HIV-1

Identifier

NCT04404049

Link

https://clinicaltrials.gov/study/NCT04404049

Phase

Phase II

Status

Completed

Sponsor

UBP Greater China (Shanghai) Co., Ltd

More details

This is a Phase II, randomized, open-label, multi-center, active-controlled study to assess the safety, tolerability, and efficacy of UB-421 administered as an add-on to the standard ART in ART-treated HIV-1 subjects with stably suppressed HIV-1 plasma VL. The study will be conducted at multiple study centers, designated AIDS hospitals in China.

Purpose

The HIV Functional Cure Potential of UB-421 in ART Stabilized HIV-1 Patients

Interventions

Intervention 1

Intervention 2

Countries

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
2023-12-01

Actual Start Date
Not provided

Anticipated Date of Last Follow-up
2022-05-16

Estimated Primary Completion Date
2024-06-30

Estimated Completion Date
2025-06-30

Actual Primary Completion Date
Not provided

Actual Completion Date
Not provided

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

Inclusion Criteria: 1. HIV-1 sero-positive 2. Male with body weight ≥ 50 kg or female with body weight ≥ 45 kg. 3. HIV-1 plasma RNA level below 50 RNA copies/mL. Exclusion Criteria: 1. Subjects with active systemic infections, except for HIV-1, that the Investigator feels the infections may confound evaluation and treatment for HIV-1. 2. Current active hepatitis B carriers, ie, hepatitis B surface antigen positive. 3. Current active hepatitis C carriers, ie, hepatitis C virus (HCV) antibody positive. 4. History of anaphylaxis to other mAbs. 5. Any vaccination within 8 weeks prior to the first dose of assigned drug. 6. Use of immunomodulators, HIV vaccine, or systemic chemotherapy within 180 days prior to the first dose of assigned drug. 7. Females who are pregnant, lactating, or breastf

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

39

Allocation

Randomized

Intervention model

Parallel Assignment

Intervention model description

possibly counterpart of NCT03743376 in China

Masking

Open label

Masking description

Not provided

Frequency of administration

Studied LA-formulation(s)

Studied route(s) of administration

Use case

Treatment

Key resources

UBP-A205-HIV

Identifier

NCT03164447

Link

https://clinicaltrials.gov/study/NCT03164447

Phase

Phase II

Status

Completed

Sponsor

United BioPharma

More details

This is a Phase 2, multi-center study, designed to evaluate the efficacy, safety, and tolerability of UB-421 in conjunction with a failing existing ART regimen for 1 week and optimized background therapy (OBT) for 24 weeks, respectively.

Purpose

UB-421 Combine With Optimized Background Therapy Regimen in Multi-Drug Resistant HIV-1 Infection Patients

Interventions

Intervention 1

Intervention 2

Countries

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
2023-12-01

Actual Start Date
Not provided

Anticipated Date of Last Follow-up
2023-04-21

Estimated Primary Completion Date
2024-03-01

Estimated Completion Date
2024-05-01

Actual Primary Completion Date
Not provided

Actual Completion Date
Not provided

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

Inclusion Criteria: 1. Males and females, age ≥18 years; 2. HIV-1 seropositive, with documented HIV-1 infection by official, signed, written history (eg. Laboratory report); 3. Receiving a combination antiretroviral therapy (cART) (failing regimen) for at least 8 weeks before Screening and are willing to continue on the failing regimen during the Screening Phase and up to Day 14 of the Treatment Phase, OR have failed in the past 8 weeks of Screening and are off therapy and are willing to stay off therapy until Day 14 of the Treatment Phase; 4. Plasma HIV-1 RNA ≥ 1000 copies/mL at the Screening Visit and documented detectable viral load (HIV-1 RNA \>200 copies/ml) within the last 3 months prior to the Screening Visit; 5. Highly treatment-experienced HIV-infected patients with documented ge

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

10

Allocation

Not provided

Intervention model

Single group assignment

Intervention model description

Not provided

Masking

Open label

Masking description

Not provided

Frequency of administration

Studied LA-formulation(s)

Studied route(s) of administration

Use case

Treatment

Key resources

UBP-A230-HIV

Identifier

NCT04985890

Link

https://clinicaltrials.gov/study/NCT04985890

Phase

Phase II

Status

Active, not recruiting

Sponsor

UBP Greater China (Shanghai) Co., Ltd

More details

* To assess the impact of UB-421 and chidamide in changing HIV-1 viral reservoir profile among HIV-1 suppressed patients who undergo short-term ART interruption. * To evaluate the safety and tolerability of UB-421 combined with chidamide among HIV-1 suppressed patients who undergo short-term ART interruption.

Purpose

A Proof of Concept Study to Evaluate the Effect of UB-421 in Combination With Chidamide on HIV Viral Reservoir

Interventions

Intervention 1

Intervention 2

Countries

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
2024-03-01

Actual Start Date
Not provided

Anticipated Date of Last Follow-up
2023-05-09

Estimated Primary Completion Date
2026-12-01

Estimated Completion Date
2027-12-01

Actual Primary Completion Date
Not provided

Actual Completion Date
Not provided

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

Inclusion Criteria: Subjects are eligible to be included in the study only if ALL of the following criteria apply: 1. HIV-1 sero-positive, with documented HIV-1 infection by official, signed, written history. 2. Male with body weight ≥ 50 kg or female with body weight ≥ 45 kg, aged 18 years or older. 3. Have been receiving at least (≧) 2 nucleoside/ nucleotide reverse transcriptase inhibitors (NRTI) plus one non-nucleoside reverse transcriptase inhibitor (NNRTI), protease inhibitor (PI, either boosted or un-boosted), integrase strand transfer inhibitor (INSTI) or entry inhibitor (EI) for more than 1 years. 4. Have more than 2 different alternative options of optimized ART regimen. 5. HIV-1 plasma viral load (VL) level well suppressed below 50 RNA copies/mL for at least (≧) 12 months. 6.

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

20

Allocation

Randomized

Intervention model

Parallel Assignment

Intervention model description

Not provided

Masking

Open label

Masking description

Not provided

Frequency of administration

Studied LA-formulation(s)

Studied route(s) of administration

Use case

Treatment

Key resources

UBP-A127-HIV

Identifier

NCT04620291

Link

https://clinicaltrials.gov/study/NCT04620291

Phase

Phase I

Status

Unknown status

Sponsor

United BioPharma

More details

UB-421 subcutaneous formulation (UB-421 SC) is developed to provide HIV infected patients a more convenient drug delivery method. UB-421 SC injection, with significantly less injection time than IV infusions and with opportunity of self-administration or administered in general medical setting (in addition to HIV-specific clinic), can provide patient a more convenient option. This UB-421 SC phase I study will be conducted to investigate short-term safety, pharmacokinetics and anti-viral activity of UB-421 SC at three dose levels in ART-treated aviremic subjects and treatment naive HIV-infected subjects. The current UB-421 SC formulation (125 mg/ml) is at least 10-fold more concentrated than UB-421 IV (10 mg/ml). The highly concentrated formulation makes weekly UB-421 subcutaneous injectio

Purpose

Study for Evaluation of the Safety, Pharmacokinetics, and Antiviral Activity of UB-421 Subcutaneous Formulation in HIV Infected Adults

Interventions

Intervention 1

Countries

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
2023-12-31

Actual Start Date
Not provided

Anticipated Date of Last Follow-up
2022-05-12

Estimated Primary Completion Date
2025-12-31

Estimated Completion Date
2025-12-31

Actual Primary Completion Date
Not provided

Actual Completion Date
Not provided

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

Inclusion Criteria: ART-treated aviremic subjects who meet all inclusion criteria (A\~C and 1\~5) will be eligible for Part A: A. Documentation of continuous ART treatment with suppression of plasma viral level below the limit of detection for ≥1 years. Individuals with "blips" (i.e., detectable viral levels on ART) prior to the Screening Visit (SV) may be included provided they satisfy the following criteria: 1. The blips are \<400 copies/mL, and 2. Succeeding viral levels return to levels below the limit of detection on subsequent testing B. Tolerated the baseline ART regimen (without major toxicity) and are expected to continue in the trial period (since SV till EOS) the same ART regimen. The change in brand or formulation but not in the 3 ARV types (eg, from 3 tablets to 1 single tab

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

18

Allocation

Not provided

Intervention model

Sequential assignment

Intervention model description

Not provided

Masking

Open label

Masking description

Not provided

Frequency of administration

Studied LA-formulation(s)

Studied route(s) of administration

Use case

Treatment

Key resources

UBP-A122-HIV

Identifier

NCT04620304

Link

https://clinicaltrials.gov/study/NCT04620304

Phase

Phase I

Status

Completed

Sponsor

United BioPharma

More details

This is a phase I, open-label, dose-escalation study to investigate short-term safety, pharmacokinetics, and antiviral activity of UB-421 SC with 4 weekly doses in treatment naive HIV-1 infected patients. Eligible (n=6 per dose cohort) subjects will be sequentially enrolled into 3 escalating-dose cohorts to receive 4 weekly fixed doses of UB-421 SC at either 250 mg (Cohort A), 500 mg (Cohort B) or 700 mg (Cohort C). Subjects should be followed for safety for additional 4 weeks after the last UB-421 SC dosing. In order to control viral load while minimizing confounding in safety assessment, subjects can initiate standard anti-retroviral therapy (ART) two weeks after the last UB-421 SC dosing. Escalation to the next higher dose cohort will be determined based on dose limited toxicity (DLT)

Purpose

Study for Evaluation of the Safety, Pharmacokinetics, and Antiviral Activity of UB-421 Subcutaneous Formulation Administered in HIV-1 Infected Treatment Naive Patients

Interventions

Intervention 1

Countries

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
Not provided

Actual Start Date
2021-01-01

Anticipated Date of Last Follow-up
2023-04-21

Estimated Primary Completion Date
Not provided

Estimated Completion Date
Not provided

Actual Primary Completion Date
2022-05-25

Actual Completion Date
2022-05-25

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

Inclusion Criteria: 1. HIV-1 seropositive, with documented HIV-1 infection by official, signed, written history (e.g. laboratory report); 2. Male and female, age 20 years or older; 3. Asymptomatic (generalized lymphadenopathy can be included), defined as subjects without stage 3 defining opportunistic illnesses according to revised Surveillance Case Definition for HIV Infection published in 2014, which was determined by the Investigator based on the medical history, physical examination, ECG, and laboratory evaluations; 4. CD4+ (D1) T cell count \> 350 cells/mm3 at the Screening Visit; 5. HIV-1 viral load \> 5,000 copies/mL at the Screening Visit; 6. HIV antiretroviral therapy (ART)-naïve i.e., subjects who receive no prior or current HIV antiretroviral drugs; 7. Male subjects and female

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

15

Allocation

Not provided

Intervention model

Sequential assignment

Intervention model description

Not provided

Masking

Open label

Masking description

Not provided

Frequency of administration

Studied LA-formulation(s)

Studied route(s) of administration

Use case

Treatment

Key resources

220008

Identifier

NCT05582694

Link

https://clinicaltrials.gov/study/NCT05582694

Phase

Phase II

Status

Withdrawn

Sponsor

National Institute of Allergy and Infectious Diseases (NIAID)

More details

Background: People with HIV usually take a combination of 2 or more anti-HIV drugs daily to help manage their infection. Sometimes, however, HIV becomes resistant to these drugs, and the infection cannot be treated. Untreated HIV infection can make people more vulnerable to other infections as well as some cancers. Better treatments are needed for people with drug-resistant HIV. Objective: To see if a study drug (UB-421) is effective in people with drug-resistant HIV. Eligibility: People aged 18 years and older with HIV that is resistant to anti-HIV drugs. Design: Participants will be in the study for 35 weeks. Participants will have separate screening and baseline visits within 2 months of each other. They will have a physical exam with blood and urine tests both times. On the sec

Purpose

A Trial of Anti-CD4 Antibody UB-421 in Combination With Optimized Background Antiretroviral Therapy in Patients With Multi-Drug Resistant HIV-1 Infection

Interventions

Intervention 1

Countries

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
Not provided

Actual Start Date
2025-07-10

Anticipated Date of Last Follow-up
2025-07-10

Estimated Primary Completion Date
Not provided

Estimated Completion Date
Not provided

Actual Primary Completion Date
2025-07-10

Actual Completion Date
2025-07-10

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

* INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: * Ability to provide informed consent; * Stated willingness to comply with all study procedures and availability for the duration of the study; * Aged 18 years or older; * Have a life expectancy that is \>6 months (as judged by the Principal Investigator \[PI\]); * HIV-1 seropositive; * Have a history of being treated for at least 6 months with ART; * Plasma HIV-1 RNA \>= 1,000 copies/mL at the Screening visit; * Screening CD4+ T cell counts of \> 350 cells/mm3; * Documented genotypic or phenotypic resistance to at least one ARV drug within three or more drug classes of ARV medications; * Receiving a stable failing regimen of cART for at least 8 weeks before

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

Not provided

Allocation

Not provided

Intervention model

Single group assignment

Intervention model description

Not provided

Masking

Open label

Masking description

Not provided

Frequency of administration

Studied LA-formulation(s)

Studied route(s) of administration

Not provided

Use case

Treatment

Key resources

UBP-A213-HIV

Identifier

NCT04041362

Link

https://clinicaltrials.gov/study/NCT04041362

Phase

Phase II

Status

Withdrawn

Sponsor

United BioPharma

More details

This study assess the safety, tolerability, and efficacy in reducing viral load and proviral DNA of UB-421 administered as an add-on to the ART in ART-experienced viremic HIV-1 subjects.

Purpose

the Study to Evaluate the Safety of UB-421 in Combination With Antiretroviral Therapy (ART) and the Efficacy in Reduction of HIV Viral Load and Proviral DNA as Compared to ART Alone in ART-experienced

Interventions

Intervention 1

Intervention 2

Countries

Not provided

Sites / Institutions

Not provided

Trials dates

Anticipated Start Date
2020-04-01

Actual Start Date
Not provided

Anticipated Date of Last Follow-up
2020-02-18

Estimated Primary Completion Date
2020-12-01

Estimated Completion Date
2021-03-01

Actual Primary Completion Date
Not provided

Actual Completion Date
Not provided

Studied populations

Age Cohort

• Adults
• Older Adults

Genders

• All

Accepts pregnant individuals
Unspecified

Accepts lactating individuals
Unspecified

Accepts healthy individuals
No

Comments about the studied populations

Inclusion Criteria: 1. HIV-1 seropositive 2. Male with body weight ≥ 50 kg or female with body weight ≥ 45 kg. 3. have been receiving antiretroviral therapy (ART) for more than 2 years Exclusion Criteria: 1. Any previous exposure to a mAb within 12 weeks prior to the first dose of UB-421 treatment. 2. Any significant diseases (other than HIV-1 infection) or clinically significant findings, including psychiatric and behavioral problems, determined during the screening period, medical history, and/or physical examination that, in Investigator's opinion, would preclude the subject from participating in this study. 3. History of anaphylaxis to monoclonal antibodies. 4. Any vaccination within 8 weeks prior to the first dose of UB-421.

Health status

Not provided

Study type

Interventional (clinical trial)

Enrollment

Not provided

Allocation

Not provided

Intervention model

Parallel Assignment

Intervention model description

Not provided

Masking

Open label

Masking description

Not provided

Frequency of administration

Not provided

Studied LA-formulation(s)

Studied route(s) of administration

Not provided

Use case

Treatment

Key resources

Proprietary excipients used

Not provided

Novel excipients or existing excipients at a concentration above Inactive Ingredients Database (IID) for the specified route of administration

Not provided

Residual solvents used

Not provided

There are either no relevant patents or these were not yet submitted to LAPaL

Publications

Effect of Anti-CD4 Antibody UB-421 on HIV-1 Rebound after Treatment Interruption

Chang-Yi Wang — NEJM — 2019-04-17

Background

Administration of a single broadly neutralizing human immunodeficiency virus (HIV)–specific antibody to HIV-infected persons leads to the development of antibody-resistant virus in the absence of antiretroviral therapy (ART). It is possible that monotherapy with UB-421, an antibody that blocks the virus-binding site on human CD4+ T cells, could induce sustained virologic suppression without induction of resistance in HIV-infected persons after analytic treatment interruption.

Methods

We conducted a nonrandomized, open-label, phase 2 clinical study evaluating the safety, pharmacokinetics, and antiviral activity of UB-421 monotherapy in HIV-infected persons undergoing analytic treatment interruption. All the participants had undetectable plasma viremia (<20 copies of HIV RNA per milliliter) at the screening visit. After discontinuation of ART, participants received eight intravenous infusions of UB-421, at a dose of either 10 mg per kilogram of body weight every week (Cohort 1) or 25 mg per kilogram every 2 weeks (Cohort 2). The primary outcome was the time to viral rebound (≥400 copies per milliliter).

Results

A total of 29 participants were enrolled, 14 in Cohort 1 and 15 in Cohort 2. Administration of UB-421 maintained virologic suppression (<20 copies per milliliter) in all the participants (94.5% of measurements at study visits 2 through 9) during analytic treatment interruption, with intermittent viral blips (range, 21 to 142 copies per milliliter) observed in 8 participants (28%). No study participants had plasma viral rebound to more than 400 copies per milliliter. CD4+ T-cell counts remained stable throughout the duration of the study. Rash, mostly of grade 1, was a common and transient adverse event; one participant discontinued the study drug owing to a rash. A decrease in the population of CD4+ regulatory T cells was observed during UB-421 monotherapy.

Conclusions

UB-421 maintained virologic suppression (during the 8 to 16 weeks of study) in participants in the absence of ART. One participant discontinued therapy owing to a rash.

Additional documents

No documents were uploaded

Useful links

• NIH Clinicalinfo drug record: Semzuvolimab — clinicalinfo.hiv.gov, 2025-12-15