Bio-Thera Solutions has announced promising clinical results for BAT8006, a novel folate receptor-α (FR-α) antibody drug conjugate (ADC), showing significant efficacy in treating platinum-resistant ovarian cancer patients. The Phase I study data, presented at the 2024 ASCO Annual Meeting, demonstrated a 37% overall response rate across all FR-α expression levels, positioning BAT8006 as a potential best-in-class treatment option.
Clinical Efficacy Demonstrates Broad Patient Benefit
As of the May 8, 2024 data cutoff, 54 patients with platinum-refractory or platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer received BAT8006 treatment at doses ranging from 1.8-2.4 mg/kg and 84/93 mg/m². Among these heavily pretreated patients, 38.9% had undergone more than three lines of prior systemic treatment.
The study revealed consistent efficacy across different FR-α expression levels. In patients with FR-α <50%, the overall response rate was 33.3% (7/21), while those with FR-α ≥50% achieved a 39.4% response rate (13/33). Notably, patients with FR-α ≥75% demonstrated the highest response rate at 46.7% (7/15).
With a median follow-up of 6.5 months, the median duration of response reached 6.3 months, and median progression-free survival was 7.47 months. The overall survival rates at 6 months and 1 year were both 83.0%, indicating durable clinical benefit.
Favorable Safety Profile Sets BAT8006 Apart
The Phase I study enrolled 156 subjects with advanced solid tumors, demonstrating BAT8006's manageable safety profile. In the optimal dose cohorts of 84 and 93 mg/m², only 3.5% and 3.9% of subjects required dose reductions, respectively. Study drug interruptions occurred in 5.3% and 13.7% of patients in these cohorts.
Importantly, no treatment-related deaths, interstitial lung disease, pneumonitis, keratitis, uveitis, or decreased vision were reported. The primary treatment-related adverse events were hematological toxicities, with grade ≥3 thrombocytopenia occurring in 9% versus 28% of patients, and neutropenia in 19% versus 37% of patients in the 84 and 93 mg/m² dose groups, respectively.
Innovative Bystander Effect Mechanism
BAT8006 incorporates Bio-Thera's proprietary anti-FR-α antibody technology coupled with a stable and cleavable ADC linker-payload system. The drug features a small molecule topoisomerase I inhibitor with potent cell membrane penetration capabilities, enabling a unique "bystander effect" that allows the drug to eliminate neighboring cancer cells beyond the directly targeted ones.
This mechanism addresses a significant challenge in cancer treatment by tackling tumor heterogeneity, where not all cancer cells within a tumor may express the target receptor at therapeutic levels.
Expanding Development Program
Bio-Thera has received FDA approval to proceed with a Phase II clinical trial for BAT8006, expanding beyond the ongoing Phase I study in China. The company is also exploring BAT8006's efficacy in endometrial carcinoma, breast cancer, and non-small cell lung cancer, with early results showing promising activity across these tumor types.
Additionally, the Chinese National Medical Products Administration recently approved a clinical study combining BAT8006 with BAT1308, Bio-Thera's PD-1 monoclonal antibody, representing a strategic approach to combination therapy development.
The comprehensive clinical data positions BAT8006 as a potentially transformative treatment for patients with FR-α expressing solid tumors, particularly those with limited treatment options in the platinum-resistant setting.
