Amgen announced that the U.S. Food and Drug Administration (FDA) has approved two new indications for Prolia® (denosumab) as a treatment to increase bone mass in men receiving androgen deprivation therapy (ADT) for non-metastatic prostate cancer. Men receiving ADT are at high risk for developing fractures, including vertebral fractures, which can cause paralysis.

“Bone loss and fractures are recognized adverse effects of hormone ablation therapies but we have not had an approved treatment option to prevent these problems for our patients,” said Matthew Smith, M.D., Ph.D., director of the Genitourinary Malignancies Program at Massachusetts General Hospital Cancer Center, Boston. “Prolia now gives us the ability to reduce the risk of bone loss and fractures, allowing patients to continue their treatment and their fight against cancer.”

The expanded indications for Prolia are based on two Phase 3 clinical trials: a three year, randomized, double-blind, placebo-controlled, multinational study involving 1,468 men with non-metastatic prostate cancer undergoing androgen deprivation therapy.

1- In men, bone mineral density (BMD) was significantly higher at the lumbar spine in patients treated with Prolia for two years compared to placebo (-1.0 percent placebo, +5.6 percent Prolia; treatment difference 6.7 percent [95 percent CI: 6.2, 7.1]; P<0.0001). 2- Additionally, after three years of treatment with Prolia, differences in BMD were 7.9 percent at the lumbar spine, 5.7 percent at the (total) hip and 4.9 percent at the femoral neck and the incidence of new vertebral fractures was 3.9 percent in the placebo-treated men compared to 1.5 percent for the Prolia treated men, representing a relative risk reduction of 62 percent (P=0.0125). The most common (per patient incidence > 10 percent) adverse reactions reported with Prolia in men with bone loss receiving androgen deprivation therapy for prostate cancer are arthralgia (joint pain) and back pain. Additionally, in Prolia treated men with non-metastatic prostate cancer receiving androgen deprivation therapy, a greater incidence of cataract adverse events was also reported. Hypocalcemia is low serum calcium levels in the blood) was reported in Prolia-treated patients.

Prolia is contraindicated in patients with hypocalcemia. Pre-existing hypocalcemia must be corrected prior to initiating Prolia. Hypocalcemia may worsen, especially in patients with severe renal impairment. All men should be adequately supplemented with calcium and vitamin D. Men receiving Prolia should not receive XGEVA®, as both Prolia and XGEVA contain the same active ingredient, denosumab.

Long term use of Prolia has not been evaluated. Anyone taking Prolia in excess of 3 years needs to be carefully monitored for additional possible side effects.

Joel T Nowak, M.A., M.S.W.