Bridge Biotherapeutics Inc. presented a poster with preclinical data updates of its drug candidate BBT-207 at the American Association for Cancer Research (AACR) 2023 annual meeting, being held from April 14 to 19 in Orlando, Florida. BBT-207, which has the potential to be a mutant selective and broad-spectrum fourth-generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor (EGFR TKI), is the company's first internally discovered drug candidate with potent activity and efficacy against a broad range of EGFR mutations in non-small cell lung cancer (NSCLC), including C797S double mutations which arise after third-generation EGFR TKI treatment. At last year's AACR annual meeting, the company disclosed initial preclinical data for BBT-207 and discussed the potency of the drug candidate against EGFR C797S double mutations inclusive of Del19/C797S (DC) and L858R/C797S (LC) as well as driver mutations including Del19 and L858R.

In this year's poster presentation, the company highlighted BBT-207's intracranial anti-tumor activity, as well as additional data showing the experimental drug's anti-tumor efficacy. In an in vivo study with an intracranial implantation model of luciferase-labeled PC-9 cells harboring EGFR Del19/T790M/C797S (DTC) mutations, BBT-207 exhibited significantly increased mouse survival rate compared to a control group. In three weeks from the baseline, both of groups treated with low-dose and high-dose of BBT-207 exhibited increased survival rate compared to the control group treated with Osimertinib.

On Day 21 of the trial, the BBT-207 low-dose group, the high-dose group, and the control group exhibited 75%, 100% and 25% of the survival rate each. Also, the bioluminescence imaging data collected from the same in vivo study demonstrated that the subjects with comparative treatment showed systemic metastases including brain metastases from Week 2, whereas BBT-207 treatment groups exhibited relatively lower level of metastases. Following last year's data disclosure, both in vitro and in vivo efficacy data included in this year's poster have shown that BBT-207 boasts robust anti-tumor efficacy.

BBT-207 demonstrated dose-dependent tumor regression efficacy against C797S double mutations from in vivo study with Osimertinib-resistant Ba/F3 CDX mouse models. The administration of 40mg/kg for 21 days resulted in significantly regressed tumor growth, with a tumor growth inhibition (TGI) rate of 107% in Del19/C797S (DC) model and 102% in L858R/C797S (LC) model. In DC model, tumor regression (TR) relative to the pre-treatment was observed in 8 out of 8 mice.

In March 2023, the company submitted an Investigational New Drug Application (IND) to the U.S. Food and Drug Administration (FDA) to enter a Phase 1/2 clinical trial of BBT-207. Bridge Biotherapeutics first released preclinical research data on BBT-207 at AACR last year.