Spectrila is a recombinant preparation of the enzyme asparaginase, licensed as a component of antineoplastic combination therapy for acute lymphocytic leukaemia in both adults and children. It is administered by intravenous infusion every three days with the dose depending on patient's age and body surface area.
The amino acid asparagine is needed for cellular protein synthesis. Lymphocytic leukaemia cells are unable to synthesise asparagine as well as normal cells, so they require the extracellular environment to provide them with the amino acid. Asparaginase hydrolyses asparagine to aspartic acid and ammonia, thus depriving the tumour cells of their asparagine supply and ultimately causing cell death.
Asparaginase produced by the bacterium Dickeya dadantii (formerly Erwinia chrysanthemi) is already used in the treatment of acute lymphocytic leukaemia as Erwinase (crisantaspase). A pegylated form of the enzyme derived from E. coli, pegaspargase (Oncaspar), is also available but currently unlicensed.