A New Urine-Based PC Assay, Clinical Trials Providing Earlier Access to New Therapies and Other News from February-March, 2012.

Banyan tree overlooking inter-coastal waterway Boca Grande, Florida. - B.J. Gabrielsen photo.

It has been a month since I last updated this website and there have been significant news items which are summarized below.

1) FDA Approves a PCA3 Urine-Based Assay for Prostate Cancer that Could Reduce Unnecessary Prostate Biopsies.  On February 15th, 2012, the U.S. Food and Drug Administration (FDA) approved a urine-based molecular diagnostic test that aids clinical decision-making for repeat prostate biopsies in men who have had a previous negative biopsy. The test, developed by Gen-Probe, is called PROGENSA PCA3 (Prostate Cancer Antigen 3) assay. It tests for levels of PCA3 in the urine of men immediately after a digital rectal examination. PCA3 is produced by a gene that is normally expressed only in human prostate tissue and is highly expressed in 95% of all prostate cancer.  Thus the product of this gene is excreted in the urine of men with prostate abnormalities. The current prostate-specific antigen (PSA) screening test for prostate cancer is prostate-specific but not highly cancer-specific which is the case for PCA3 testing which has better positive and negative predictive values. Therefore, this test will aid faster and more efficient diagnosis of prostate cancer thereby minimizing additional repeat biopsies and their undesirable side effects including infections.  Additional details are available from Gen-Probe, in the March 20th, 2012 issue of the ZeroHour Newsletter and the February 27th, 2012 issue of the Prostate Cancer Foundation NewsPulse.

2) Patients Being Recruited for Clinical Trials Involving Provenge, Zytiga and/or Hormonal Therapy. During the last 1-2 years, several new therapeutic agents have been approved by the FDA for treatment of men with metastatic prostate cancer or who have had prior chemotherapy. The strategy now seems to be the application of these agents in men with earlier stage prostate cancer. To determine the effectiveness of such strategies, two clinical trials are described involving Sipuleucel-T (Provenge), abiraterone acetate (Zytiga) and androgen deprivation (hormonal) therapy (ADT). The first is entitled “Concurrent Versus Sequential Treatment with Sipuleucel-T (Provenge) and Abiraterone (Zytiga) in Men With Metastatic, Castration-Resistant Prostate Cancer (mCRPC).” This trial may provide earlier access to Zytiga for men who have not had chemotherapy. It is currently recruiting patients in the following locations: Denver, CO; Seattle, WA and Virginia Beach, VA.

The second trial entitled “Sequencing of Sipuleucel-T (Provenge) and ADT in Men with Non-Metastatic Prostate Cancer”, may provide earlier access to Provenge for men who have recurrent but non-metastatic prostate cancer. The trial is designed to determine whether ADT (hormonal therapy) started before or after sipuleucel-T leads to superior augmentation of immune response to sipuleucel-T. This trial is currently recruiting patients in the following states: Alabama, California, Colorado, Maryland (Johns Hopkins), New York, South Carolina, Texas and Washington. For details of both trials, see the Prostate Cancer Research Institute (PCRI) Weekly (Volume 2, Issue 2) of March 2nd and 8th, 2012.

3) Oligometastatic Prostate Cancer; an Intermediate Stage? The February 27th, 2012 issue of the Prostate Cancer Research Institute (PCRI) Insights contained several articles of interest including an update on brachytherapy and especially an article on an intermediate stage of prostate cancer termed oligometastatic prostate cancer. The authors, including Dr. Charles “Snuffy” Myers, outline the concept of this intermediate stage wherein cancer has spread outside the prostate gland but is not widespread. Pros and cons of various imaging techniques used to identify such metastatic sites are described. These sites are not always easily observed  by CT or MRI scans. The authors’ focus is not merely on bone metastases but lymph node metastases as well. Identified metastatic sites are then subjected to carefully focused radiation therapy such as provided by advanced versions of Intensity Modulated Radiation (IMRT) such as Image-Guide (IG) IMRT and  Dynamic Adaptive Radiotherapy (DART 4D) therapy.

4) Continued Development of OncoGenex’s OGX-427, a New Type of Anticancer Therapy. OGX-427 is a second-generation antisense drug designed to reduce the production of heat shock protein 27 (Hsp 27), a protein that regulates multiple cell mechanisms that cancers use to survive. Hsp 27 inhibits apoptosis (cell death), is found at high level in many human tumors especially hormone-resistant prostate cancer and is implicated in cancer progression and treatment resistance. Hsp 27 can also be induced by cell stress through chemotherapy, radiation or hormonal therapy.  When co-administered with prednisone, OGX-427 demonstrated promising results in a Phase II clinical trial versus prednisone alone. A new Phase II trial of OGX-427 in men with minimally symptomatic or asymptomatic advanced prostate cancer who have not yet received chemotherapy has recently been announced. This Phase II trial will measure disease progression at 12 weeks, PSA levels, time to progression by PSA or measurable disease, numbers of circulating tumor cells (CTCs) and other endpoints.  For additional details, see the Prostate Cancer Foundation NewsLetter, February 27th, 2012 and the OncoGenex website.

5) Custirsen (OGX-011) to be Further Evaluated in Phase III Trials. OncoGenex Pharmaceuticals and its partner Teva Pharmaceuticals plan to start a new Phase III trial for custirsen in combination with Sanofi’s approved taxane chemotherapy drug, Jevtana with the goal of improving survival in prostate cancer patients. A separate trial called Synergy, which aims to test custirsen in combination with chemotherapy in hormone-resistant prostate cancer patients, is boosting its patient enrollment. For further information see the March 20th, 2012 issue of the ZeroHour NewsLetter.

6) Alpharadin Update. The February 27th, 2012 issue of the Prostate Cancer Foundation NewsPulse had several articles of interest. One was an update on the therapeutic effects of the alpha-particle emitting Alpharadin (Radium-223) which is targeted to bone metastases and potent, localized, tumor cell-killing activity within a 10-cell radius. It’s half-life of 11.4 days seems to make it an ideal candidate for cancer therapy.

 

 

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