3SBio Inc., (3SBio), a leading biotechnology company based in China focussing on researching, developing, manufacturing and marketing bio-pharmaceutical products, has entered into an exclusive licence agreement with JenKem Technology Co., Ltd (JenKem) for the development, manufacturing and marketing in Mainland China of PEG-irinotecan, a long-acting polymer-drug conjugate which inhibits topoisomerase I (Topo-I).

Topo-I is over-expressed in many solid tumours, including colorectal, ovarian, breast, glioma, and small cell and non-small cell lung cancers. Each year, approximately 1.2 million patients are diagnosed with one of these types of cancer in China.

Researchers from JenKem developed PEG-irinotecan to treat Topo-I over-expressed cancers. The first generation Topo-I inhibitor approved by the Food and Drug Administration in the United States (US FDA) in 1994 showed a high initial peak concentration and short half-life, associated with high toxicity and reduced efficacy respectively, which greatly limits its clinical applications. In contrast, the body's natural enzymatic processes gradually degrade the linkers within JenKem's larger PEG-irinotecan molecule, enabling a slow, continuous release of the active drug to passively and selectively target the leaky vasculature of tumour tissues and reducing tumour cell division by inhibiting Topo-I.

JenKem's PEG-irinotecan showed significant effects on tumour repression and toxicity in several in vivo tumour models, suggesting it may have the potential to suppress tumour growth throughout the entire chemotherapy cycle. Compared with first generation irinotecan, JenKem's PEG-irinitocan showed a 40-fold and 7-fold increase in the area under the curve (AUC) from the plasma concentration-time curve of SN-38, the active metabolite of irinotecan, in serum and tumour, respectively, as well as 7-fold increase in half-life of SN-38 in serum, while decreasing peak concentrations (Cmax) of SN-38 in serum by more than 50 per cent .

It is currently expected that the Investigational New Drug (IND) application will be filed with the China Food and Drug Administration (CFDA) by the end of 2014. 3SBio currently intends to initially develop PEG-irinotecan for metastatic colorectal cancer and breast cancer, as well as platinum-resistant ovarian cancer. In China, the incidence rates for colorectal cancer, breast cancer and ovarian cancer are 29.44 per 100,000, 42.02 per 100,000 and 5.1 per 100,000 annually.

"We are pleased to collaborate with JenKem and look forward to moving PEG-irinotecan into clinical trials," Dr. Jing Lou, chief executive officer, of 3SBio commented. "This agreement is a natural fit with our mission to develop therapies for patients with late stage or metastatic cancers. 3SBio continues to seek opportunities to develop novel drug candidates for refractory cancers and other unmet medical needs, particularly in 3SBio's core therapeutic areas of oncology, nephrology and hematology."

"PEG-irinotecan is a novel drug candidate with great potential to treat many types of solid tumours," Dr. Xuan Zhao, chief executive officer, of JenKem commented. "3SBio is an established industry leader in the innovative biological field in China, which makes them an ideal partner for long-term collaboration. Together, we can maximise this opportunity and benefit tens of thousands of Chinese patients suffering from metastatic breast cancer and colorectal cancer, platinum-resistant ovarian cancer and other severe diseases."

Irinotecan (marketed as Camptosar in the United States) is a topoisomerase I inhibitor indicated for first-line therapy in combination with 5-fluorouracil and leucovorin for patients with metastatic carcinoma of the colon or rectum; and patients with metastatic carcinoma of the colon or rectum whose disease has recurred or progressed following initial fluorouracil-based therapy. The major side effects of irinotecan include early and late forms of diarrhea, and severe myelosuppression. Irinotecan was introduced into the world market between 1994 and 1996.

PEG-irinotecan is a novel long-acting topoisomerase I inhibitor to treat Topo-I over-expressed cancers. The first generation Topo-I inhibitors show a high initial peak concentration (associated with high toxicity) and short half-life (associated with reduced efficacy). In contrast, the large PEG-irinotecan molecule is inactive when administered. PEG-irinotecan passively targets tumor tissues selectively due to their leaky vasculature and high permeability of large molecules. Over time, the body's natural enzymatic processes slowly degrade the linkers within the molecule and continuously release active drug to stop tumor cell division through inhibition of Topo-I. Therefore, the long acting drug candidate might suppress tumor growth throughout the entire chemotherapy cycle sustainably, while significantly reducing cytotoxicity by decreasing the peak exposure.

JenKem is an emerging biotechnology company in China. JenKem focuses on the development and manufacturing of high quality polyethylene glycol (PEG) products and derivatives, and related custom synthesis and PEGylation services.