Zosuquidar (development code LY-335979) is an experimental antineoplastic drug. Zosquidir inhibits P-glycoproteins. Other drugs with this mechanism include tariquidar and laniquidar. P-glycoproteins are trans-membrane

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

s that pump foreign substances out of cells in an ATP dependent fashion. Cancers overexpressing P-glycoproteins are able to pump out therapeutic molecules before they are able to reach their target, effectively making the cancer multi-drug resistant. Zosuquidar inhibits P-glycoproteins, inhibiting the efflux pump and restoring sensitivity to chemotherapeutic agents. Zosuqidar was initially characterized by Syntex Corporation, which was acquired by

Roche F. Hoffmann-La Roche AG, commonly known as Roche, is a Swiss multinational healthcare company that operates worldwide under two divisions: Pharmaceuticals and Diagnostics. Its holding company, Roche Holding AG, has shares listed on the SIX ...

in 1990. Roche licensed the drug to

Eli Lilly Eli Lilly (July 8, 1838 – June 6, 1898) was an American soldier, pharmacist, chemist, and businessman who founded the Eli Lilly and Company pharmaceutical corporation. Lilly enlisted in the Union Army during the American Civil War and ...

in 1997. It was granted

orphan drug status An orphan drug is a pharmaceutical agent developed to treat medical conditions which, because they are so rare, would not be profitable to produce without government assistance. The conditions are referred to as orphan diseases. The assignment o ...

by the FDA in 2006 for AML. In 2010, it was announced that a

phase III clinical trial The phases of clinical research are the stages in which scientists conduct experiments with a health intervention to obtain sufficient evidence for a process considered effective as a medical treatment. For drug development, the clinical phases ...

for the treatment of

acute myeloid leukemia Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal cells that build up in the bone marrow and blood and interfere with normal blood cell production. Symptoms may inclu ...

(AML) and

myelodysplastic syndrome A myelodysplastic syndrome (MDS) is one of a group of cancers in which immature blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms typically are seen. Later, symptoms may ...

did not meet its primary endpoint and Eli Lilly discontinued its development.

References

{{Reflist Experimental cancer drugs Organofluorides Cyclopropanes Quinolines Piperazines Abandoned drugs