February 14, 2018 – Today the U.S. Food and Drug Administration (FDA) approved apalutamide (Erleada, also previously called ARN-509) for the treatment of non-metastatic castration-resistant prostate cancer (non-metastatic CRPC).  This clinical setting is when men who are being treated with androgen deprivation therapy (ADT) see their PSA levels begin to rise, but no metastases are visible yet on scans.  There were previously no FDA-approved treatments for non-metastatic CRPC, and patients typically continued to receive ADT, despite its diminishing benefit.

This approval is based on results from the randomized phase 3 SPARTAN clinical trial, which was presented last week at the 2018 ASCO Genitourinary Cancers Symposium.

The SPARTAN trial, led by PCF-funded investigator Eric Small, MD (University of California, San Francisco), tested the addition of apalutamide vs. placebo in 1,207 non-metastatic CRPC patients with rapidly rising PSA (PSA doubling time of 10 months or less), in addition to whatever treatment the men were already receiving (mostly ADT).  Patients selected for the trial had no distant metastases based on a bone scan and computed tomography (CT) of the pelvis, abdomen, chest, and head.  Some patients had malignant local or regional (pelvic) lymph nodes no larger than 2cm on the short axis.

Apalutamide was found to delay the time to metastatic disease by over 24 months on average (40.5 months in the apalutamide group versus 16.2 months in the placebo group).  This represents a 72% reduction in risk of metastasis or death.  The full results from the SPARTAN study have been published in the New England Journal of Medicine.

PCF funded the synthesis of apalutamide at UCLA by chemist Michael Jung, PhD, in collaboration with prostate cancer physician-scientist Charles Sawyers, MD (now at Memorial Sloan Kettering Cancer Center).

More information on this approval can be found here.

Terms to know from this article:

androgen

A type of hormone that promotes the development and maintenance of male sex characteristics.

Placebo

An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.

Bone scan

A technique to create images of bones on a computer screen or on film. A small amount of radioactive material is injected into a blood vessel and travels through the bloodstream; it collects in the bones and is detected by a scanner.

Tomography

A series of detailed pictures of areas inside the body; the pictures are created by a computer linked to an x-ray machine.

Malignant

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

Lymph nodes

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called a lymph gland.

Metastasis

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a "metastatic tumor" or a "metastasis." The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-ta-seez).

PSA

prostate-specific antigen (PSA): A substance produced by the prostate that may be found in an increased amount in the blood of men who have prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate.

Dr. Andrea Miyahira has a PhD in cancer immunology, and is Director of Research at the Prostate Cancer Foundation.