In September 2006, Sonus initiated a Phase 1 study of SN2310, a novel camptothecin for the treatment of cancer.

 

What are Camptothecins?

 

4     Potent anticancer agents that belong to the family of drugs called topoisomerase I inhibitors.

4     Bind reversibly to the TOPO-I-DNA complex causing breaks in the DNA strands during replication– resulting in cell death

4     Due to cell-cycle dependence and reversible binding - prolonged exposure of tumors to camptothecins is necessary for effective biological activity1
 

 (1.      Clin Cancer Res.  2005; 11(11):4144-4150.)

 

 

 

Approved Topoisomerase I Inhibitors

 

 

Irinotecan (Camptosar®)

Topotecan (Hycamtin®)

Indications

Metastatic colorectal cancer   Component of 1st line with 5-FU and
  leucovorin
 

  or when disease has recurred or

  progressed following initial
  5-FU- based therapy

Ovarian (2nd line)         

 SCLC (2nd line)

2006 Sales ($MM)

$ 903 (WW)

$ 225 (WW)

Limitations

Pro-drug requires enzymatic hydrolysis with approx. 3% conversion to active drug (SN38)
 

Half-life:   Irinotecan = 5.8 hours     

               SN-38 = 10.4 hours
 

Diarrhea is a DLT

Short half-life requires daily dosing

 

 

  

 Structural Comparison of SN2310 and Irinotecan

 

 

 

 

 

SN2310: The Value Proposition 

 

Enhanced PK

4     Longer half life and higher exposure to SN-38

4     Potential for improved anti-tumor activity and/or better tolerability

4     Potentially more convenient dosing schedules in combination therapy

 

Convenience/Ease of Use

4     Reduced duration of administration

4     Ready-to-use formulation

 

Intellectual Property

4     1 issued US COM patent; other geographies pending