Hana Biosciences, a biopharmaceutical company focused on advancing cancer care, recently announced that the US Food and Drug Administration (FDA) has granted orphan drug designation for vincristine sulfate(Drug information on vincristine sulfate) liposomes injection (Marqibo) in the treatment of adult patients with acute lymphoblastic leukemia (ALL).
"This designation underscores the need for improved therapies in ALL, and supports our development strategy in areas of unmet medical need," commented Greg Berk, MD, senior vice president and chief medical officer. "Hana Biosciences is committed to the clinical development of Marqibo in ALL and other lymphoproliferative diseases."
In December 2006, Hana filed a Special Protocol Assessment (SPA) with the FDA for liposomal vincristine in adults with ALL in second relapse and beyond. Subject to agreement with the FDA on the SPA, Hana targets initiation of its pivotal trial in the first half of 2007.
About Liposomal Vincristine
Marqibo utilizes vincristine encapsulated in a rigid, lipid bilayer of sphingomyelin. Vincristine, an FDA-approved, standard chemotherapeutic used in most lymphoma and ALL regimens, is a cell-cycle-specific agent whose activity is dependent on the duration of drug exposure. The sphingosome encapsulated technology employed by Marqibo results in a more rigid liposome that is designed to allow the active vincristine to leak out of the liposome slowly, maintaining drug levels for prolonged periods of time. This improved pharmacokinetic profile, which mimics a continuous vincristine infusion, potentially results in greater activity in rapidly dividing cancers. The anticipated activity associated with vincristine has traditionally been limited by its short half-life, and its inability to be dose-escalated beyond 2 mg due to neurotoxicity.
In phase I and II clinical trials, liposomal vincristine has been shown to have a significantly longer half-life, and patients have been able to tolerate doses that are approximately 100% greater than conventional vincristine. These trials provide the rationale for utilizing this technology in lymphoproliferative diseases such as ALL, Hodgkin's, and non-Hodgkin's lymphoma.
A hematologically stable CML patient developed a solitary, exquisitely painful ulceration, 7 cm × 5 cm, located on the mid-medial foreleg. There was never any evidence of venous insufficiency. The patient denied the possibility of a spider bite. What is the likely cause of this lesion?
