New clinical trial of odanacitib (MK0822) in castration-resistant prostate cancer

Merck & Co. has announced the future initiation of a prospective, randomized, double-blind, multi-center Phase III clinical trial of their development-stage agent odanacatib (MK0822). This drug is to be tested in patients who have been medically or surgically castrated. The objective of the trial is to see if odanacitib (pronounced oh dan assi tib ) can delay the time to first bone metastasis compared to a placebo.

For detailed information about this trial, please click here. The trial is not yet enrolling patients, but is scheduled to open for enrollment in August. Total trial enrollment is projected at 1,550 patients. It is not clear from the trial description whether this trial is limited to patients from specific regions only, but North America there is a toll-free number that you can call to find out more information.

Odanacitib is a cathepsin K inhibitor that is being tested in the treatment of osteoporosis, in women with breast cancer, and now in men with advanced prostate cancer. Formal published data on this drug is limited. However, there is some limited information available on various web sites, as follows:

There are several limitations on eligibility for this trial, which you are advised to read with care. Unfortunately many patients who might have bee interested in and willing to participate in this trial will discover that they are not eligible for one of the reasons described below:

• You must have castration-resistant prostate cancer (i.e., you must have a rising PSA subsequent to medical or surgical castration).
• You must have received a bliateral orchiectomy at least 180 days prior to your first study visit or be receiving androgen-deprivation therapy and have been on a stable regimen for at least 90 days prior to your first study visit.
• You can not have any bone metastases or any history of bone metastases
• You can not have any other distant metastases (with the exception of regional lymph nodal metastases).
• You can not be currently receiving any form of bisphosphonate or other drug therapy for osteoporosis.
• You can not have been treated with  an oral bisphosphonate for osteoporosis for more than 3 months within the 2 years prior to your first study visit, or for a total of more than 6 months at any time prior to youir first study visit
• You can not have been treated with an intravenous bisphosphonate within the 12 months prior to your first study visit.
• You can not have received any form of chemotherapy within the 2 years prior to your first study visit (e.g., doxorubicin, cytoxan, estramustine, paclitaxel, docetaxel, etoposide, vinblastine, 5-fluorouracil, interferon, mitoxantrone).
• You can not have a history of any cancer other than prostate cancer within 5 years prior to signing informed consent, except for adequately treated basal cell or squamous cell skin cancer.
• You can not be currently participating in, or have participated in a study with an investigational compound or device within 30 days of signing the informed consent.
• You can not be currently participating in or have at any time in the past participated in a prostate cancer study using a medication approved by the regulatory agency in the region in which you live which was being tested for the treatment of prostate cancer (an unapproved indication)
• You can not be using a systemically administered azole antifungal (e.g., ketoconazole, fluconazole, itraconazole, miconazole, posaconazole, ravuconazole, and voriconazole) while participating in this trial. Patients taking these medications must discontinue their use at least 1 week prior to starting to use their blinded study medication in this clinical trial.

Published, peer-reviewed data on odanacitib appears to be limited. However, there is information on a number of web sites, of which the following is representative:

• Increased bone mineral density seen in Phase IIB study with odanacatib, formerly MK-0822, an investigational cathepsin K inhibitor