History of intraperitoneal platinum drug delivery for ovarian cancer and its future applications.

Intraperitoneal (IP) delivery of cisplatin was developed in the 1970s based on a strong pharmacologic rationale and rodent models. Its advantage over intravenous (IV) administration was supported initially by observational studies in treating recurrent ovarian cancer and eventually by better outcomes from IP IV cisplatin in randomized studies in patients undergoing optimal surgical debulking at diagnosis. In the past two decades, with the introduction of novel anticancer interventions (such as taxanes, bevacizumab, inhibitors of DNA repair, and immune check point inhibitors), advantages of IP drug delivery are less clear and concerns are raised on cisplatin's therapeutic index. The discovery of BRCA genes and their key role in DNA repair, on the other hand, have strengthened the rationale for IP drug delivery: high grade serous cancers arising in the Mullerian epithelium in association with hereditary or somatic BRCA function inactivation are linked to peritoneal spread of cells that - while initially sensitive - are prone to emergence of platinum resistance. Therefore, selection of patients based on genomic features and focusing on the better tolerated IP carboplatin are ongoing. Recent examples of leveraging the peritoneal route include (1) targeting the cell membrane copper transport receptor - that is shared by platinums - by the combination of the proteasome inhibitor bortezomib and IP carboplatin; and (2) enhancing IP 5-fluoro-2-deoxyuridine cytotoxicity when coupled with PARP inhibition.