Carbetimer is a low molecular weight polymer derived from ethylene and maleic anhydride with potent antineoplastic activity. Preclinical studies have shown antitumor effects against many tumor cell lines including B 16 melanoma. Its antitumor actions are felt to include both reduction of uridine and cytidine nucleoside triphosphate as well as the diminution of pyrimidine salvage by inhibiting uridine, cytidine, and thymidine kinase. Besides direct antiproliferative effects, Carbetimer could act through immunomodulation, as suggested by the induction of cytotoxic T-cells in mice and the discordant in vitro and in vivo activities against the Lewis lung carcinoma model. Unfortunately, Carbetimer failed to demonstrate efficacy in Phase II trials

Sizofiran (Schizophyllan, SPG, Sonifilan, Sizofilan) is a soluble beta-D-glucan produced by the Basidiomycetes fungus, Schizophyllum commune Fries, with potential immunomodulating and antitumor activities. Although sizofiran’s exact mechanism of action has yet to be fully elucidated, this agent appears to stimulate the immune system by increasing cytokine production, activating macrophages and Langerhans cells and enhancing the activity of polymorphonuclear leukocytes (PML) and natural killer (NK) cells. Sizofiran was found rather ineffective against gastric cancer, but extended survival time in patients with head and neck cancer. In cervical cancer, Sizofiran prolonged survival and time to recurrence for stage II cases but not stage III, and showed added effectiveness when injected directly into the tumor mass. Sonifilan is used as a biological response modifier (BRM) with radiation therapy for cancer treatment in Japan. It was launched for cervical cancer in South Korea in 1998.

Lentinan is a polysaccharide extracted from Shiitake mushrooms and used as an adjuvant therapeutic drug in treating patients with lung cancer in China. Lentinan is mainly composed of β-glucan with anti-tumor, anti-inflammatory, anti-diabetes properties, and other therapeutic properties. Lentinan was approved as an adjuvant for stomach cancer therapy in Japan in 1985. It is approved for treating multiple types of cancer, hepatitis, and other diseases in China. Lentinan is available as capsules, tablets, and injections. The capsules and tablets of lentinan is taken orally as a traditional medicine. Intravenous injection of lentinan is clinically approved and used in hospital with a dose of 1–1.5 mg/day. Low blood pressure, allergy, urgent appeal, and dizziness were the major side effects.