The Setting Where Progress Has Stalled
Squamous non-small cell lung cancer has been the stubborn corner of lung cancer research. The better-known mutations that opened the door to targeted therapy cluster in the adenocarcinoma subtype, and immunotherapy has helped, but the patients who progress after chemotherapy and immunotherapy, the previously treated squamous group, face a standard of care with a median survival typically under a year.
Into that setting, BioNTech and OncoC4 presented data this week at the IASLC World Conference on Lung Cancer in Seoul from Stage 1 of the PRESERVE-003 Phase 3 trial. The headline number: median overall survival of 18.5 months for gotistobart versus 10.0 months for docetaxel, the chemotherapy standard. The hazard ratio was 0.56, a 44 percent reduction in the risk of death, with a nominal p-value of 0.0295.
The numbers deserve their full context, because the data cut holds both promise and caveat in the same table. The analysis covered 87 patients, 45 on gotistobart and 42 on docetaxel, with a median follow-up of 25.4 months and a data cutoff in July. That is a small group, and Stage 1 of the trial is not the confirmatory portion.
What the Drug Actually Is
Gotistobart, also known as BNT316 or ONC-392, is not another checkpoint antibody of the familiar kind. It is a pH-sensitive antibody targeting CTLA-4, designed to deplete regulatory T cells selectively inside the acidic tumor microenvironment while sparing them elsewhere in the body. The design logic is that the toxicity of ordinary CTLA-4 blockade, colitis chief among them, comes largely from activity outside the tumor.
The safety data show the tension inherent in that promise. Grade 3 or higher treatment-related adverse events occurred in 44.4 percent of the gotistobart group versus 48.8 percent on docetaxel, which the companies describe as manageable, but separate reporting has flagged serious treatment-related events of 44.4 percent versus 29.3 percent and discontinuations of 15.6 percent versus 4.9 percent, with colitis the most common severe event on the investigational arm.
For a patient population facing docetaxel's own considerable toxicity, a survival signal of this size would be meaningful even with a heavier side-effect burden. But the burden is real, and it is the first thing regulators will weigh against the survival curve.
The Pivotal Test Is Already Running
The structure of PRESERVE-003 matters more than usual here. Stage 1 generated the signal. Stage 2, the pivotal portion, is running at more than 160 sites globally with overall survival as the primary endpoint, and an interim readout is expected around the end of the year. That is the number that could support approval, and it will either confirm the near-doubling or shrink it, as confirmatory data routinely do.
The companies are also reading the data against the competitive field. Squamous lung cancer has attracted a new generation of agents, including Summit's ivonescimab and other bispecific antibodies, several of which appeared alongside gotistobart at the same conference. The survival bar those programs are setting against chemotherapy is the same bar gotistobart just cleared in a small cohort.
For patients with previously treated squamous disease, none of this changes today's options. Gotistobart remains investigational, and the standard of care is unchanged until confirmatory data and regulatory review. What the presentation changes is the odds that the end of the year brings a signal worth watching in a disease that has waited a long time for one.
Primary sources
- Nasdaq coverage of the PRESERVE-003 data for the survival results and trial details.
- BioNTech and OncoC4 announcement via GlobeNewswire for the companies' presentation of the updated data.
- Fierce Biotech on the survival standard and safety details for the serious adverse event figures.