Jeanny B. Aragon-Ching, MD, is the clinical program director of genitourinary cancers at the Inova Schar Cancer Institute. She is board certified in medical oncology, hematology and internal medicine and has a special interest in caring for patients with prostate, bladder, kidney and testicular cancers.
Prostate cancer is an extremely common disease. More than 3 million men in the United States are living with it; an estimated 11.6 percent of all men in the US will be diagnosed with prostate cancer at some point in their lives.
In many men, slow growth of cancer calls for monitoring or active surveillance, with no immediate need for treatment. In others, rapidly progressing disease requires intervention to prevent it from spreading throughout the body.
Fortunately, new treatments give men with more aggressive or advanced types of prostate cancer better options for treatment, and the progress has been incredibly rapid. Because September is Prostate Cancer Awareness Month, I’m taking the opportunity to examine one type of treatment that has advanced dramatically just in the past 12 months, and another that appears poised to make progress in years to come.
Novel anti-androgens assert themselves
One of the first steps that oncologists often take to slow the growth of prostate cancer is known as androgen deprivation therapy (ADT). It essentially means using drugs (rarely surgery) to reduce the production of male hormones like testosterone, which drive the growth of the cancer.
Eliminating the hormone supply often slows or stops the cancer’s growth. But in many cases, it continues to grow. In these cases, which account for about 100,000 men in the US, cancer eventually spreads to other parts of the body, making it much more difficult to treat.
Antiandrogens are a class of drugs that further reduce any lingering growth signals still being received by the cancer after androgen deprivation therapy. Last year, the US Food and Drug administration approved two new antiandrogens, apalutamide and enzalutamide, for treatment of men whose cancer has not responded to ADT, but has not yet spread beyond the prostate. In July of this year, it approved a third, darolutamide. In clinical trials, all three treatments roughly doubled the time it takes for these cancers to start spreading to the bones and other sites in the body, from less than 18 months to three years or more.
While studies comparing which of these three drugs is better and which offer the best balance between effectiveness and side effects for various patients are currently inexistent, physicians and patients alike often would have to talk about which treatments would best suit them. For example, darolutamide, the most recently approved of the three drugs, may have an advantage in resulting in fewer neurologic side effects like mental impairment because it does not cross the blood-brain barrier.
This year also saw the first approval of an antiandrogen for patients who have not yet responded to ADT, but have nevertheless seen their prostate cancer spread. Studies presented at the American Society of Clinical Oncology meeting in June showed that two of the three drugs mentioned in the previous section, apalutamide and enzalutamide, could extend survival in patients with this type of disease. On September 17, the FDA approved apalutamide for these patients.
Targeted radiotherapy shows promise
In some men, prostate cancer continues to spread even after ADT, chemotherapy, antiandrogens and other currently available therapies have been tried. With no remaining treatments available, these men can have limited survival.
Yet a recent study of a therapy that delivers radiation directly to prostate cancer cells offers hope. A treatment called LuPSMA combines a radioactive isotope of a rare chemical called lutetium with an antibody that binds to molecules commonly found on the surfaces of prostate cancer cells. In the body, the antibody component attaches LuPSMA to cancer cells, and the radioactivity emitted by the lutetium component kills them.
Earlier this year at the Genitourinary Cancers Symposium, Australian researchers presented the results of LuPSMA for 50 patients with aggressive prostate cancer who had exhausted most or all of their other treatment options. The treatment reduced prostate-specific antigen (PSA), a measure of prostate cancer activity, by more than half in 32 of the 50 patients. In 22 patients, PSA fell by 80 percent or more.
The study was not designed to evaluate LuPSMA’s effect on survival, but men who saw their PSA decline by more than half saw their survival double, on average, to 18 months. Even more encouraging, eight patients did not complete the treatment protocol because their cancers retreated so dramatically.
These results are still very preliminary, but they suggest that LuPSMA and other targeted radiotherapies could be valuable not just for patients with advanced disease, like those in the study, but for those in earlier stages of prostate cancer. Two full clinical studies of LuPSMA are now underway, one comparing it with current standard-of-care treatment and the other to chemotherapy.
New developments like these give us hope. Since 1992, the prostate cancer mortality rate has fallen by more than half. With new treatments like the ones described here, and more on the horizon, we can expect even more progress.
My colleagues and I in the Inova Genitourinary Cancer Program are constantly monitoring the latest advances in the field of prostate cancer, attending and leading scientific conferences and collaborating with our peers at other institutions to continue working on changes in prostate cancer treatment. We pride ourselves on delivering the highest quality care and offering the latest, most promising treatments. We also participate in clinical trials to help keep the field moving forward. You can find an Inova clinical trial for GU cancers online, or learn more about the personalized care and talented specialists at the Inova Genitourinary Cancer Program.