About sorafenib in castration-resistant prostate cancer

Angiogenesis inhibition in prostate cancer: current uses and future promises

Angiogenesis has been well recognized as a fundamental part of a multistep process in the evolution of cancer progression, invasion, and metastasis. Strategies for inhibiting angiogenesis have been one of the most robust fields of cancer investigation, focusing on the vascular endothelial growth factor (VEGF) family and its receptors. There are numerous regulatory drug approvals to date for the use of these agents in treating a variety of solid tumors. While therapeutic efficacy has been established, challenges remain with regards to overcoming resistance and assessing response to antiangiogenic therapies. Prostate cancer is the most common noncutaneous malignancy among American men and angiogenesis plays a role in disease progression. The use of antiangiogenesis agents in prostate cancer has been promising and is hereby explored.

Angiogenesis inhibitors in the treatment of prostate cancer

IMPORTANCE OF THE FIELD

Prostate carcinoma is the most common non-cutaneous malignancy in U.S. men. The efficacy of docetaxel and prednisone in metastatic castrate-resistant prostate cancer (mCRPC) has been shown to improve overall survival; however, its effect is not durable, highlighting the need for new therapies.

AREAS COVERED IN THIS REVIEW

We will review the development of some of the leading compounds with direct and indirect antiangiogenic activity in prostate cancer including antibodies to VEGF and its receptors, small-molecule inhibitors of downstream signaling, immunomodulatory drugs with antiangiogenic activity, and compounds thought to directly inhibit or destroy vascular endothelial cells.

WHAT THE READER WILL GAIN

The reader will gain a basic understanding of the role of angiogenesis in prostate cancer growth and metastasis. Current and potential targets of angiogenesis and their corresponding drugs under development for prostate cancer are discussed.

TAKE HOME MESSAGE

There are now multiple early-phase clinical trials of antiangiogenic agents alone or in combination in prostate cancer. Several of these agents are now in Phase III development. Combined therapy with two antiangiogenic compounds may improve the activity of either compound alone. Multiple targets in the angiogenesis pathway continue to be elucidated and should remain an active area of investigation for the treatment of prostate cancer.

Safety and efficacy of sorafenib in patients with castrate resistant prostate cancer: a Phase II study

PURPOSE

We determined the safety and efficacy of sorafenib in patients with castrate resistant prostate cancer (CRPC).

METHODS

Sixty-four chemotherapy and radiotherapy naïve patients with CRPC received 400 mg sorafenib orally twice daily in 6-week cycles. All patients had bone metastasis, while 16 had lymph node-, 9 had liver-, and 10 had lung metastases. Treatment was continued until disease progression or excessive toxicity.

RESULTS

All patients were assessable for response. A median of 6.4 consecutive cycles was administered per patient. Median overall survival for all patients was 14.6 months (confidence interval [CI], 8.2-22.2). No complete response (CR) occurred. Of the 35 patients with measurable extraosseous disease, 7 (20%) had a partial response. Overall, 13 patients (20.3%; 95% CI, 4%-32%) achieved a 50% or greater reduction (partial response [PR]) in prostate-specific antigen (PSA) level after two cycles. The median response duration was 2.5 months (95% CI, 1.4 to 4.8), and the median time to progression was 5.9 months (95% CI 3.6 to 7.6). There was no treatment-related death. Toxicities were well tolerated.

CONCLUSIONS

Sorafenib demonstrated some antitumor activity. Further studies are necessary to determine a subgroup of patients who would likely respond better to sorafenib.