Light Sciences Oncology, a Snoqualmie, Wash., developer of light-activated cancer drugs and delivery systems, raised $15 million in a second venture round despite having an IPO on file with the SEC, VentureWire reports (subscription required). Fidelity Investments provided the funding.

The company’s lead product is Litx — a combination of a normally inert drug that is activated when exposed to specific wavelengths of light and a flexible light-emitting diode that can be inserted into solid tumors much like a biopsy needle. When energized by light from the diode, the drug reacts with nearby oxygen molecules, shearing them apart into free radicals that destroy surrounding tumor tissue. The notion is to provide a localized anti-tumor effect that is generally free of side effects. The system is undergoing tests in brain, liver and colon cancer.

Light Sciences filed to raise up to $41.9 million in an IPO last September.