Data Readout

NovaBridge's ragistomig posts Q6W safety edge ahead of H2 2026 Phase 1 readout

A December 2025 dose-expansion update showed lower liver toxicity on a less frequent dosing schedule, setting up further data from the same Phase 1 trial by year-end 2026.

By AppliedXLJuly 13, 2026Trial NCT04762641

Executive Summary

The trial's Q6W dosing update showed a tolerability gain over the original Q2W schedule while disease control stayed comparable, giving the sponsor a rationale to keep expanding the less frequent regimen.
The pending disclosure extends that same expansion cohort and will show whether the tolerability advantage holds as more patients accumulate on the higher, less frequent dose.
No other clinical-stage program shares this bispecific's dual target in tumors, so the readout has no direct benchmark and functions as an early test of a mechanism that has not yet been validated in this setting.
The trial's completion date has slipped over multiple years, but its cadence of regular conference disclosures suggests the delay reflects an expanding dose-finding design more than stalled execution.

The trial and its endpoint

NCT04762641 is a Phase 1, open-label, dose-escalation and dose-expansion study of ABL503 (ragistomig) in patients with progressive, locally advanced or metastatic tumors who have relapsed on or are refractory to standard therapy. Its primary endpoint is the number of subjects with dose-limiting toxicities, aimed at establishing the maximum tolerated dose and recommended Phase 2 dose. The study has enrolled toward a target of 100 patients across sites in the United States and South Korea since dosing the first patient in April 2021. NCT04762641

What already read out

At the ESMO Immuno-Oncology Congress on December 10, 2025, the companies presented dose-expansion data from a 20-patient safety cohort (17 evaluable for efficacy) dosed at 3 mg/kg every six weeks (Q6W). The disease control rate was 58.8%, close to the 64.3% seen on the earlier every-two-week (Q2W) schedule, while severe Grade 3 or higher liver enzyme elevations fell to 5% from 40% on Q2W, with no discontinuations and no cytokine release syndrome. The company also reported CD8+ T-cell expansion consistent with immune activation, and said the results support advancing ragistomig into combination studies. I-MAB

What the next disclosure will test

A 10-patient cohort at a higher 5 mg/kg Q6W dose is dosing now, and the company has said it plans to evaluate this cohort further, with the seed's catalyst pointing to additional data expected in the second half of 2026. That update will show whether the tolerability gain seen at 3 mg/kg extends to the higher dose, and whether disease control improves, holds, or degrades as the evaluable population grows beyond the 17 patients reported in December. I-MAB

Competitive and mechanistic context

No competitor trial in the sourced landscape shares ragistomig's PD-L1 x 4-1BB dual-target design in tumors; the closest listed comparators, including durvalumab, gotistobart, and belzutifan, target different mechanisms such as PD-L1 alone, CTLA-4, or HIF-2alpha. That leaves ragistomig without a validated same-mechanism precedent in this population, and the trial itself is the source of whatever base rate exists for the combined checkpoint and costimulatory approach.

Timing and protocol history

The trial's primary completion date has moved twice, from June 2023 to June 2025 and then to November 2025, alongside an enrollment target increase from 36 to 100 patients. Those changes track with a design that expanded from initial dose-escalation into added expansion cohorts, and the trial has continued to generate scheduled conference disclosures, including the December 2025 ESMO-IO poster, through the same period. NCT04762641+1

This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.