Talaporfin (INN, also known as aspartyl chlorin, mono-L-aspartyl chlorine e6, NPe6, or LS11) is a photosensitizer used in photodynamic therapy (PDT). It absorbs red light at 664nm normally provided by a laser tuned to this wavelength. Talaporfin was approved in Japan (in 2004) for PDT of lung cancer and marketed as Laserphyrin.
Development status: talaporfin was approved in Japan in 2004, but not yet in USA. Light Sciences Oncology (LSO) is developing Aptocine™ (talaporfin sodium) for solid tumors as well as other indications such as BPH. Aptocine is a water-soluble drug targeted by a small, single-use, disposable drug activator included with the drug. Aptocine is designed to provide tolerable, effective, and repeatable treatments for patients. LSO has completed treatment of patients in a Phase 3 trial of Aptocine in hepatocellular carcinoma (HCC) and in a Phase 3 trial for metastatic colorectal cancer (MCRC). LSO is also conducting clinical trials in benign prostatic hyperplasia (BPH), or enlargement of the prostate, and has clinical or preclinical programs in cardiovascular, ophthalmic, and dermatologic diseases. Aptocine has three potential primary mechanisms of action: direct tumor cytotoxicity, apoptosis due to vascular shutdown, and anti-tumor immune stimulation. In clinical studies to date, Aptocine has been well-tolerated with no evidence that Aptocine causes the serious toxicities associated with traditional cancer treatments. (source: http://www.lsoncology.com/).
Chemical and physical properties of Talaporfin: Talaporfin is dark blue-green powder, soluble in water. Talaporfin is also hygroscopic and light sensitive. Therefore talaporfin should be stored under dry and protected from light (easily way to this is to use alumina foil to wrap the container). Talaporfin's absorption max (phosphate buffer, pH 7.4): 400 nm, 654 nm (e 180000, 40000). Absorption max (dioxane): 402 nm, 663 nm (EmM 111, 38).
Useful data about talaporfin sodium:
The singlet oxygen quantum yield of talaporfin was 0.5– 0.8 (0.56 in water and 0.77 in methanol). Talaporfin sodium has a serum t1⁄2 alpha of 9 hours and is excreted unmetabolized, predominantly by the biliary system. ( Cancer . 2003 Oct 15;98(8):1767-71.)
Original Literature References of Talaporfin: Semisynthetic derivative of chlorin e6, q.v. Photosensitizer activated at 664 nm by laser or light-emitting diode-based light infusion device. Causes irreversible tumor blood vessel closure. Prepn: J. C. Bommer, B. F. Burnham, EP 168831; eidem, US 4675338 (1986, 1987 both to Nippon Petrochemicals). Photophysical properties: J. D. Spikes, J. C. Bommer, J. Photochem. Photobiol. B 17, 135 (1993); L. Li et al., ibid. 67, 51 (2002). Chemical and NMR structural studies: S. Gomi et al., Heterocycles 48, 2231 (1998). Safety assessment in treatment of refractory solid tumors: R. A. Lustig et al., Cancer 98, 1767 (2003). Clinical evaluation in lung cancer: H. Kato et al., Lung Cancer 42, 103 (2003).
