Continuing to build its oncology pipeline, Spectrum Pharmaceuticals Inc. has in-licensed lucanthone, a radiation sensitizer in clinical development to treat cancers of the central nervous system.

The Irvine, Calif.-based company acquired worldwide, exclusive rights for the product from Robert Bases, who invented a method of treating cancer by administering lucanthone in combination with radiation therapy. Lucanthone is being evaluated in Phase II trials at the Montefiore Medical Center in New York.

Spectrum could not be reached for comment. Financial terms of the license agreement were not disclosed.

Originally marketed as an antiparasitic drug in the 1950s and 1960s, lucanthone was discontinued after more effective antiparasitic treatments became available. But the small molecule's past has provided it with a proven safety record, having been given to more than 300,000 patients with no lasting side effects.

Spectrum said lucanthone has shown in preclinical studies to inhibit post-radiation DNA repair in tumor cells, which results in a loss of cancer cell viability. Researchers have attributed that response to lucanthone's ability to inhibit AP endonuclease and topoisomerase II. In his studies, Bases also reported that the product has no hematological or gastrointestinal toxicity.

Spectrum said lucanthone is able to quickly cross the blood-brain barrier, which might make it a promising drug to use, along with radiation, against brain tumors, as well as other difficult-to-treat cancers.

Lucanthone marks the second radiation sensitizer in Spectrum's pipeline, though it is much further along in development than the company's synthetic prodrug, EOquin. Spectrum is in preclinical development with EOquin as an adjunct to radiation treatment, and the company has said it plans to begin clinical testing next year. EOquin also is being evaluated in Phase II trials as a treatment for bladder cancer.

The company's development efforts also include a Phase III-stage compound, satraplatin, in hormone-refractory prostate cancer. SPI-153, a fourth-generation luteinizing hormone-releasing hormone antagonist, is in Phase II studies for hormone-dependent prostate cancer. Another compound, elsamitrucin, designed to treat non-Hodgkin's lymphoma, also is in Phase II.

Spectrum acquired rights in January to RenaZorb, two preclinical, second-generation, lanthanum-based phosphate-binding drugs that use nanoparticle technology to treat hyperphosphatemia, or high phosphate levels in the blood, in kidney disease patients. A month later, the company added anther compound, that one an endothelin B agonist, which is being evaluated to enhance the therapeutic index of chemotherapeutic agents by improving tumor perfusion and increasing the delivery of cancer agents to tumor tissue.

Shares of Spectrum (NASDAQ:SPPI) fell 2 cents Tuesday to close at $4.75.