Gotistobart lifts median OS in PRESERVE-003 stage 1 squamous NSCLC

What happened

BioNTech and OncoC4 reported the first median overall-survival data from the non-pivotal stage 1 portion of PRESERVE-003, NCT05671510, on 14 September 2026. ^[1] At the 17 July 2026 data cut-off, with median follow-up of 25.4 months, 87 patients with metastatic squamous NSCLC after progression on prior immunotherapy and chemotherapy had been randomized: 45 to gotistobart monotherapy and 42 to docetaxel. ^[1]

Median overall survival was 18.5 months with gotistobart versus 10.0 months with docetaxel, with a hazard ratio of 0.56 and nominal p-value of 0.0295. ^[1] Grade 3 treatment-related adverse events were reported in 20 of 45 patients receiving gotistobart, 44.4%, and 20 of 42 patients receiving docetaxel, 48.8%. ^[1]

PRESERVE-003 is a two-stage, open-label Phase 3 trial comparing gotistobart monotherapy with standard-of-care chemotherapy, docetaxel, in squamous NSCLC after progression on PD-(L)1 inhibitors and platinum-based chemotherapy. ^[1] BioNTech’s 14 September 2026 Form 6-K says the company and OncoC4 announced these first median OS data and attached the press release as Exhibit 99.1. ^[2]

Why it matters

The competitive signal is not just the 8.5-month median OS separation; it is that the separation came from CTLA-4 monotherapy against docetaxel in a population already exposed to PD-(L)1 therapy and platinum chemotherapy. ^[1] Gotistobart is described in the SEC-filed release as an investigational CTLA-4-targeting immunotherapy designed to selectively deplete regulatory T cells within the tumor microenvironment and restore anti-tumor immune activity. ^[1]

That matters because stage 1 showed an OS separation versus docetaxel without a higher reported grade 3 TRAE rate, although the dataset is small and non-pivotal. ^[1] The grade 3 treatment-related adverse-event rate was numerically lower with gotistobart than docetaxel in stage 1, at 44.4% versus 48.8%, but the dataset is 87 randomized patients and the stage was non-pivotal. ^[1]

Published records also support the mechanism’s biological rationale. ^[3][4] Nature Medicine described PRESERVE-003 as a two-stage Phase 3 trial of BNT316/ONC-392, a pH-sensitive anti-CTLA-4 antibody that selectively depletes regulatory T cells within the tumor microenvironment, in metastatic squamous NSCLC. ^[3] A September 2026 Journal of Clinical Pharmacology article described gotistobart as an investigational humanized IgG1 monoclonal antibody targeting CTLA-4, engineered to preserve CTLA-4 through endosomal recycling while enhancing intratumoral regulatory T-cell depletion. ^[4]

Who is exposed

The direct comparator pressure is on docetaxel-based chemotherapy in metastatic squamous NSCLC after PD-(L)1 and platinum progression. ^[1] PRESERVE-003 explicitly tests gotistobart monotherapy against docetaxel in that setting, so any sponsor using chemotherapy control assumptions in a similar post-immunotherapy squamous population now has to decide whether an 18.5-month median OS signal is a new planning benchmark or a stage 1 outlier. ^[1]

The result also changes how CTLA-4 should be discussed in lung-cancer portfolio reviews. ^[1] Before the pivotal portion reads out, Prognyx’s read is that gotistobart has moved CTLA-4 from a legacy-checkpoint category into an active competitive hypothesis in post-PD-(L)1 squamous NSCLC, because the dossier reports the survival separation for gotistobart monotherapy and separately describes the antibody as tumor-microenvironment-selective CTLA-4/T-reg biology. ^[1][3][4]

What we could not verify

The provided dossier does not include a ClinicalTrials.gov excerpt confirming current registry status, enrollment, primary completion date, study completion date, or results-posting status for PRESERVE-003.

What to watch next

The next decision point is the pivotal stage 2 portion of PRESERVE-003, which BioNTech and OncoC4 said on 14 September 2026 was ongoing at more than 160 sites globally. ^[1] BioNTech’s 20 August 2026 WCLC preview had already said updated overall-survival data from stage 1 would be presented at WCLC 2026 and that the pivotal stage 2 part was ongoing. ^[5]

There is no dossier-supported pivotal readout date, PDUFA date, EMA review clock, or regulatory filing date for gotistobart in this indication. ^[1][5] Until a dated pivotal catalyst appears, the operational watch item is whether the stage 2 population, comparator performance, and safety profile preserve the stage 1 survival direction at larger scale. ^[1]

The now-what

For a company with a post-immunotherapy squamous NSCLC program, a reasonable first move is to stress-test power, control-arm and differentiation assumptions against a 10.0-month docetaxel median OS comparator and an 18.5-month gotistobart signal. ^[1] The stage 1 sample is too small to treat as a new standard, but too specific to ignore in trial-design sensitivity work. ^[1]

For BD teams, Prognyx’s interpretation is that the practical question is whether gotistobart may create partnering scarcity around CTLA-4 designs that claim tumor-microenvironment-selective T-reg depletion. ^[1][3][4] The answer should wait for pivotal stage 2, but scouting should not wait for the press release that names a filing path. ^[1]

For clinical teams, the relevant competitor file is narrow: squamous NSCLC, prior PD-(L)1 exposure, prior platinum chemotherapy, monotherapy versus docetaxel, and OS as the decision metric. ^[1] Broad CTLA-4 enthusiasm outside that frame is not supported by the lung-cancer dossier. ^[1]

Verdict: medium-to-high competitive threat, with the window to act before pivotal stage 2 could convert a survival signal into a registrational claim. ^[1]