Guan Huashi (left) discusses experimental plans with researchers at a laboratory in Qingdao, Shandong province. CHINA DAILY

For generations, families along the coast of Chile have boiled a seaweed known as cochayuyo into soups and stews. Half a world away, in a laboratory in Qingdao, East China's Shandong province, scientists are turning the same seaweed into a potential cancer treatment.

Chinese researchers saw in the traditional South American food ingredient more than just nutrition. They identified unusually high concentrations of a specific beta-glucan — a natural compound believed to have strong immune modulating properties.

After more than a decade of research, the discovery has evolved into BG136, the world's first marine polysaccharide-based immunotherapy drug candidate to reach clinical trial for cancer treatment. Researchers said recently that the drug is expected to begin combination therapy trials soon.

BG136 was jointly developed by Ocean University of China, the Marine Biomedical Research Institute of Qingdao and Conson Pharmaceutical Group, a local marine pharmaceutical manufacturer.

"Unlike conventional cancer drugs that directly attack tumors, BG136 is designed to activate the body's innate immune system, helping immune cells recognize and fight cancer more effectively," said Yu Guangli, a professor at Ocean University of China and chief scientist at the Marine Biomedical Research Institute of Qingdao.

"The mechanism could make it a broad-spectrum therapy with potential applications in multiple tumor types."

The journey from food soup to medical drug began with an unexpected setback. Around 2010, Yu's team had been researching mushroom-derived beta-glucan for cancer treatment when raw material shortages disrupted the project, forcing researchers to search for alternatives from the ocean. "The pharmaceutical potential hidden in the ocean remains largely unexplored," Yu said, adding that marine organisms live in extreme environments and produce unique bioactive compounds rarely found on land.

Samples of BG136 on display. CHINA DAILY

Researchers spent years overcoming one of the biggest challenges in marine drug development: how to separate and manufacture high-purity marine polysaccharides at an industrial scale while maintaining quality consistency and safety.

Du Changyu, a senior executive overseeing drug development at Conson Pharmaceutical Group, said the company dispatched a research team to Chile to secure stable, high-quality seaweed raw materials. The team surveyed hundreds of seaweed samples across a 4,000-kilometer stretch of coastline, conducting extensive screening and component analysis before establishing a three-dimensional quality evaluation system. The effort increased the qualification rate of raw materials from 30 percent to 90 percent, laying the groundwork for the drug's stability and safety, Du said.

According to Hu Ting, a key member of Yu's team, BG136 was approved for human trials in late 2022 and completed Phase I clinical testing in March 2024, demonstrating safety and tolerability across escalating doses. The drug recently completed its Phase II monotherapy trials, focusing on colorectal cancer to further evaluate efficacy and optimize dosing. Researchers found that weekly — or even biweekly — injections achieved therapeutic effects comparable to, and in some cases better than, the original once-every-three-days regimen, potentially reducing treatment burdens for patients.

The development of BG136 reflects growing global interest in marine drug discovery, a field long viewed as promising but challenging because of the complexity of marine organism-derived compounds.

In recent years, China has accelerated the development of its marine biopharmaceutical sector. A research team led by Guan Huashi, an academician at the Chinese Academy of Engineering and professor of Ocean University of China, has built one of the world's largest marine carbohydrate compound libraries to support new drug discovery, as the coastal city advances its ambition to become an international hub for health, wellness, and rehabilitation industries.

Despite rapid growth, China's marine biopharmaceutical industry remains relatively small in scale and contributes only modestly to the broader marine economy, said Professor Zhang Junfeng, president of Ocean University of China.

Wang Minggang, president of Conson Pharmaceutical, said new drug development is a long journey requiring sustained investment and generations of scientific dedication. Zhang called for stronger national-level platforms in marine biomedicine, including key laboratories, industrial technology centers, and pilot-scale testing bases, to better integrate research resources, accelerate drug development and strengthen the full innovation chain from discovery to commercialization.

The Qingdao Area of the China (Shandong) Pilot Free Trade Zone, also known as the Qingdao FTZ, where the company is based, has provided strong support through its growing life and health industry ecosystem, abundant marine research resources and targeted policy support.