Chances are you’ve heard of the prostate cancer drugs Zytiga (abiraterone), Xtandi (enzalutamide) and Erleada (apalutamide) even if you haven’t been prescribed any of the three agents yourself.
They are among a collection of new drugs introduced in the past 5-10 years that have totally transformed how we treat prostate cancer. Others you may also recognize include Xofigo (radium-223) and Provenge (sipuleucl-T.)
One way of treating prostate cancer is of course to block androgens, which are male hormones. (Prostate cancer feeds on these male sex hormones.) This usually works for a while, but eventually some prostate cancers continue to grow even in very low androgen levels.
We now understand that these particular tumors have become so sensitive to androgens that they only need a very little bit to grow. Androgen levels are therefore higher in a prostate cancer tumor than in a normal prostate.
Newer drugs like Xtandi (enzalutamide) and Erleada (apalutamide) work by blocking these androgens from binding to the androgen receptor more effectively than earlier drugs. Zytiga (abiraterone) works by reducing androgen levels much more effectively than earlier drugs. Originally approved for men with metastases whose prostate cancers are resistant to hormonal therapy only after chemotherapy stopped working, researchers have been diligently exploring whether or not these agents are useful in other settings—i.e. before chemotherapy or in men without metastases.
Those explorations have panned out: men with metastatic prostate cancer resistant to hormonal therapy are now prescribed Zytiga (abiraterone) and Xtandi (enzalutamide) as an initial treatment. And men with prostate cancer resistant to hormonal therapy but without metastases are prescribed Erleada (apalutamide). All drugs extend life and extend the amount of time before the cancer appears to be growing on imaging studies.
What isn’t so clear are the implications of the early use of these agents— both in terms of side effects and financial burden on patient, nor why some men appear to become resistant to the drugs after a period of time.
Read the conversations this month carefully and then forward to your doctor. Even if your particular situation doesn’t warrant their use today, educating yourself about them will serve you well: if your doctor ever does suggest you use one of these agents, the two of you can have an informed in-depth discussion about whether they’re right for you.