UB-621

UB-621 is an experimental antibody designed to block HSV by binding glycoprotein D on the virus. A 15-person Phase 1 study in healthy adults was completed, but no results were posted to ClinicalTrials.gov and no complete primary human-results paper was identified through September 5, 2026.

Three Phase 2 studies were registered for recurrent genital HSV-2, but their records are stale: two are now labeled unknown status, and one still says not yet recruiting despite estimated dates that have passed or are near completion. HSVHQ found no checked evidence that any of the three enrolled or dosed participants.

A current China-based developer says the program remains active and describes a Phase 2 filing planned for 2026. That statement does not establish that a new trial has been submitted, cleared, or started.

UB-621 is a fully human monoclonal antibody derived from a precursor clone called E317. It is designed to bind HSV glycoprotein D, which the virus uses during entry into cells and cell-to-cell spread.

The clinical program has focused on subcutaneous dosing. The registered patient studies were designed for adults with recurrent genital HSV-2, while developer materials describe a broader intended HSV scope.

The completed Phase 1 study tested single-dose safety, tolerability, and pharmacokinetics in healthy volunteers; it was not designed to test whether UB-621 reduced herpes symptoms or shedding.

The three registered Phase 2 designs proposed to measure genital HSV-2 shedding, lesions, recurrences, safety, and pharmacokinetics using different dose schedules and comparison structures.

NCT02346760 enrolled 15 healthy adults between December 2015 and January 2017 in an open-label single-dose Phase 1 study. The registry describes four escalating-dose cohorts.

The developer reports five dose levels, three injection-site adverse events, no serious adverse event, dose-limiting toxicity, or detected anti-drug antibodies, and an estimated 23-to-28-day half-life. Those are sponsor-reported summary observations, not a complete independently appraised trial report, and the five-versus-four cohort discrepancy remains unresolved.

NCT03595995, NCT04714060, and NCT04979975 later described three Phase 2 designs. None has posted results, and none has a sufficiently current public status record to show that enrollment occurred.

No reliable human efficacy finding was identified in the checked public record. The only completed registered human study involved healthy volunteers and measured safety and pharmacokinetics, not clinical benefit for recurrent herpes.

A peer-reviewed mouse study reported that maternally transferred E317 protected neonatal mice against HSV challenge. This supports preclinical biological activity for the antibody lineage but does not show that UB-621 treats or cures HSV in people.

Developer statements suggesting therapeutic effects in Phase 1 or cure-like results in mouse models exceed what the checked public human evidence can establish.

The most defensible evidence-maturity label is early human evidence because UB-621 has been administered in a completed Phase 1 study, but the publicly available human evidence is too limited to establish efficacy or a well-characterized safety profile.

Registered Phase 2 protocols show what sponsors intended to study. Stale not-yet-recruiting or unknown-status records do not show that a trial actually started, finished, or produced a result.

UB-621 is not established as an approved or clinically available HSV treatment in the checked sources.

HSVHQ classifies UB-621 as an active Phase 1-stage program with Phase 2 planning, not as an executed Phase 2 program. That wording preserves the completed first-in-human study and the absence of checked Phase 2 execution evidence.

Current mainland-China rights and development are described by Genesis Life Science. The older trial records name United BioPharma or UBP Greater China as sponsors, so organizational and trial status should not be flattened into one uninterrupted current record.

The next evidence-changing milestone would be a regulator or registry record showing that a defined Phase 2 study was authorized and began enrollment, followed by complete results.

A complete Phase 1 report would also materially improve the evidence base by resolving cohort, safety, and pharmacokinetic details that are currently available only as a developer summary.