BEIJING – Yisheng Biopharma Co. Ltd., of Beijing, said it has inked a pact with U.S. biotech Tavotek Biotherapeutics, of Ambler, Pa., to co-develop a combination therapy with Yisheng’s YS-ON-001/002 and Tavotek’s Tavo-301/303, which the companies hope could prove a more efficacious cancer treatment than the popular anti-PD-1/PD-L1 monotherapies.