MacroGenics Inc. presented clinical update data for its antibody drug conjugate candidate MGC026 at the European Society for Medical Oncology (ESMO) conference on October 23, 2026. The company highlighted the drug’s early profile in squamous cell carcinoma of the head and neck (SCCHN), positioning the indication as a lead candidate for further development.
In a slide deck filed as an exhibit to an 8-K report, MacroGenics stated that MGC026 demonstrated durable antitumor activity across multiple indications in early clinical trials. The company emphasized a differentiated safety profile in Phase 1, citing a low discontinuation rate, no cases of interstitial lung disease (ILD), and no ocular toxicity.
The presentation positioned MGC026 within the emerging category of B7-H3-targeting ADCs, a space the company described as having significant market interest and broad clinical validation in more than 15 different tumors. MacroGenics noted that multiple major pharmaceutical partnerships have been announced in this sector. The company stated that MGC026 is well-positioned for combination with immune checkpoint inhibitors.
For SCCHN, MacroGenics indicated that emerging clinical data in heavily pretreated patients suggest a competitive profile. The company suggested this may enable positioning in early lines of treatment and in combination with other complementary agents. The slide deck identified multiple addressable subpopulations within SCCHN, including patients based on PD-L1 positive and HPV positive status.
MacroGenics described MGC026 as designed to be a potential best-in-class B7-H3 ADC. The drug features a unique B7-H3 antibody selected to bind an epitope with limited normal tissue reactivity, a site-specific highly stable cleavable linker, and a silenced Fc-domain. The payload is exatecan at a drug-to-antibody ratio (DAR) of 4. The company claimed the exatecan payload is more potent than deruxtecan in side-by-side comparisons, with improved bystander killing, based on non-clinical data from Watanabe et al. in ACS Omega, 2025.
A comparison table in the presentation contrasted MGC026 with competing B7-H3 ADCs: ifinatamab deruxtecan (I-DXd), risvutatug rezetecan (HS-20093/GSK5764227), YL201, and DB-1311/BNT345. MGC026 uses a GlycoConnect linker with a silenced Fc domain, while competitors use various tetrapeptide or tumor microenvironment activatable linkers with wild-type or silenced Fc domains. Dosing for MGC026 was listed as 7.5 mg/kg every 3 weeks, compared to 12.0 mg/kg every 3 weeks for I-DXd and 8.0 and 10.0 mg/kg every 3 weeks for risvutatug rezetecan.
The company included a cautionary note that no head-to-head clinical trials have been conducted evaluating MGC026 against competing molecules. Differences exist between study designs and participant characteristics, and the company advised caution when comparing data across studies. All comparisons between MGC026 and competing B7-H3 ADCs presented were based on non-clinical data.
MacroGenics also outlined its pipeline strategy, indicating that other B7-H3 ADCs have established evidence of clinical activity across multiple cancers, including prostate cancer, nasopharyngeal carcinoma, osteosarcoma, cervical cancer, ovarian cancer, endometrial cancer, esophageal cancer, hepatocellular carcinoma, pancreatic cancer, small cell lung cancer, non-small cell lung cancer, and breast cancer. The company noted ongoing registrational trials for non-MacroGenics indications.