Amidst the excitement and promise of new immunotherapies, is the opportunity to use existing therapies in new ways to improve outcomes for patients with genitourinary cancers, delegates attending the Clinical Oncological Society of Australia annual meeting have heard.

Dr Craig Gedye, from Hunter Medical Research Institute and the University of Newcastle, told the conference that evidence was growing for smarter ways to use existing drugs.

“We need to be making good use of the treatments we have as well as getting excited by new immune drugs coming along.”

“We’ve got these drugs that can be very potent but they run out of puff or they are very potent for 10% of people and the problem is we are wasting time with 90% of people.”

Dr Gedye said changing up the timing and administration of existing drugs were some of the ways forward.

“One of the hormone treatments used at the end of a man’s life in prostate cancer – abiraterone – can be used up front when the prostate cancer spreads and it seems to be associated with improved outcomes.”

He said the phase 3 ENZAMET trial by the ANZUP Cancer Trials Group was hoping to confirm the abiraterone results with the competing drug enzalutamide.

“Another smart idea is if you have a potent treatment for cancer and are controlling the cancer that you can possibly stop treatment and let the cancer start to grow again before re-treating the patients with the same treatment.”

He said sequentially controlling the cancer, allowing it to grow again, controlling it and allowing it to grow again not only gave patients the opportunity for time off treatment without side effects but might also result in a better overall outcome by balancing treatment sensitive cells with resistant cells.

“It’s a provocative idea that this adaptive treatment might be the way forward. Data in kidney cancer is the first out there. It’s not proved conclusively but is a really interesting idea.”

“By taking the effective treatment away, you end up using the sensitive cells to control the resistant cancer cells and try and push the whole cancer as a population back to equilibrium.”

“No person has cancer. They have cancers – a diversity of cells that explains why treatment fails. Pounding away with the strongest drug continuously and grinding down the cancer eventually selects out the super-cancer cells that will then defeat the treatment.”

Dr Gedye said drug repurposing had become a priority area under the Medical Research Future Fund.

“The classic example is thalidomide which did horrible things to babies but a whole group of those drugs is now treating multiple myeloma.”

He added that the KeyPAD trial opening soon would test immunotherapy with repurposed denosumab in metastatic clear cell renal carcinoma.

“It might actually target a population of immune cells that have been enslaved by the cancer – tumour associated macrophages. We’re hoping to show denosumab helps the immune drug to work better in patients with kidney cancer.”

Dr Gedye said genitourinary cancers as a group accounted for about 20% of all cancers. They predominantly affected men and excluding prostate cancer, had little advocacy.