Valspodar (PSC833) is an

experimental cancer treatment Experimental cancer treatments are mainstream medical therapies intended to treat cancer by improving on, supplementing or replacing conventional methods (surgery, chemotherapy, radiation, and immunotherapy). However, researchers are still try ...

and chemosensitizer. It is a derivative of

ciclosporin Ciclosporin, also spelled cyclosporine and cyclosporin, is a calcineurin inhibitor, used as an immunosuppressant medication. It is a natural product. It is taken orally or intravenously for rheumatoid arthritis, psoriasis, Crohn's disease, ...

D (cyclosporin D). Its primary use is as an inhibitor of the efflux transporter

P-glycoprotein P-glycoprotein 1 (permeability glycoprotein, abbreviated as P-gp or Pgp) also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1) or cluster of differentiation 243 (CD243) is an important protein ...

. Previous studies in animal models have found it to be effective at preventing

cancer cell Cancer cells are cells that divide continually, forming solid tumors or flooding the blood with abnormal cells. Cell division is a normal process used by the body for growth and repair. A parent cell divides to form two daughter cells, and these d ...

resistance to

chemotherapeutics Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...

, but these findings did not translate to clinical success.

Adverse effects

Valspodar can cause nerve damage.

References

{{Reflist, refs= {{cite book, last1=Wilkes, first1=Gail, last2=Ades, first2=Terri B., title=Consumers Guide to Cancer Drugs, url=https://books.google.com/books?id=d66G21_3tTUC&pg=PA226, access-date=29 May 2013, year=2004, publisher=Jones & Bartlett Learning, isbn=9780763722548, page=226 {{cite book, last1=Tao, first1=Jian'guo, last2=Sotomayor, first2=Eduardo., title=Hematologic Cancers: From Molecular Pathobiology to Targeted Therapeutics , year=2012, publisher=Springer, isbn=9789400750289, page=335 Experimental cancer drugs Cyclic peptides