SAN DIEGO, March 8, 2010 (GLOBE NEWSWIRE) -- Harbor BioSciences Inc. (Nasdaq:HRBR) said today it had reported encouraging data from its ongoing Phase I/IIa clinical trial with Apoptone® (HE3235) for castration resistant prostate cancer (CRPC) – also referred to as hormone resistant prostate cancer – at the ASCO Genitourinary Cancers Symposium in San Francisco on March 6, 2010. Preliminary results from this study, conducted with participating member sites of the Prostate Cancer Clinical Trial Consortium (PCCTC), were first reported on November 16, 2009. Apoptone is a novel steroid analog of a dihydrotestosterone metabolite that has been found to induce cell death (apoptosis) in prostate tumors.
"Due to the initial observation of disease stabilization that we have seen in late-stage patients, we have worked with the PCCTC on a planned 226 patient Phase IIb trial in both taxane-resistant and taxane-naïve CRPC patients," commented Dwight Stickney, M.D., Chief Medical Officer of Harbor BioSciences. "The Phase I/IIa trial was designed as a dose escalation study; and we acquired sufficient data to select the doses that will be used in the Phase IIb trial," Dr. Stickney added.
R. Bruce Montgomery, M.D., Associate Professor, Department of Medicine, Division of Oncology, University of Washington School of Medicine, and lead investigator of the ongoing Phase I/IIa clinical trial, presented the updated Apoptone data at the ASCO symposium on March 6, with the results described below.
Apoptone Clinical Study Update
To date, 42 taxane-resistant prostate cancer patients have been entered into the clinical trial at 7 dose levels. Of these 28 (67%) reached their first reassessment (two 28-day cycles), 15 (56%) of these had stable disease on scans or imaging and have received 1-8 additional treatment cycles before disease progression. Six patients continue to receive treatment. The Kaplan-Meier estimate(1) for the median time to progression is 15.3 weeks (range 4-40) for this ongoing trial. Due to early signs of activity, the 20 mg dose group was expanded to include 14 patients for which the data are essentially complete. Eleven of these were evaluable with an actual median time to progression of 20 weeks (range 8-28). Changes in PSA levels were consistent with the properties of this class of agent. The drug has been well tolerated and dose escalation has proceeded to 350 mg per day with no overt dose-limiting toxicities reported.
"Despite current treatments, there is an ongoing need for novel oral agents that can control the growth of prostate cancers that are progressing on conventional therapies or hormone treatments – and it is encouraging that, thus far, the drug has been well tolerated and shown evidence of disease control," said Howard Scher, M.D., Chief of the Genitourinary Oncology Service at Memorial Sloan-Kettering Cancer Center and Principal Investigator of the PCCTC.
The Phase I/IIa trial, reported by Dr. Montgomery, is an open-label study with the primary objective of assessing safety, tolerability, pharmacokinetics and activity of Apoptone in men with CRPC and an ECOG performance status score of less than or equal to 2 (ambulatory and capable of at least self-care). Patient cohorts are defined by oral daily doses of 10 mg, 20 mg, 30 mg, 50 mg, 100 mg, 200 mg and 350 mg. Subjects are treated on 28-day cycles until toxicity or disease progression; CT and bone scans are obtained every two cycles to assess progression. Responding patients in both the chemotherapy-experienced and chemotherapy-naive groups will continue to be offered treatment under the current protocol for the balance of 2010 as appropriate.
Based on these encouraging signs of activity, the PCCTC recommended an extension of the current trial into patients that have not been treated with taxane chemotherapy. Accordingly, the subject eligibility criteria were amended to include earlier-stage, chemotherapy-naive patients in a 100 mg expansion cohort and 10 patients have been enrolled to date.
About Prostate Cancer
Over one million men in the United States have prostate cancer; approximately 90,000 of these patients have late-stage prostate cancer, resulting in approximately 28,000 deaths each year. There are currently no approved treatments for end-stage (hormone and chemotherapy refractory) prostate cancer and the survival time is estimated to be between 8 and 12 months.
About Harbor BioSciences, Inc.
Harbor BioSciences is a development-stage company with two product candidates in clinical trials: Apoptone in the cohort expansion portion of a Phase I/IIa trial of patients with late-stage prostate cancer, and Triolex® (HE3286), in a Phase IIa trial in obese type 2 diabetes mellitus patients. Apoptone and Triolex represent the lead candidates from Harbor BioSciences' small molecule platform based on metabolites or synthetic analogs of endogenous steroid hormones. For more information on Harbor BioSciences please visit www.harborbiosciences.com.
(1) Kaplan-Meier Estimate is the standard statistical method for predicting the outcome of an ongoing study.
This press release contains forward-looking statements within the meaning of the federal securities laws concerning, among other things, our focus on attaining proof-of-concept data for Apoptone in its initial indication of CRPC; our planned 226 patient Phase IIb trial in both taxane-resistant and taxane-naive CRPC patients; and the continuation of treatment, with Apoptone, of men with CRPC for the balance of 2010 under our current Apoptone Phase Ib/IIa Clinical Trial protocol. Any statement included in this press release that are not a description of historical facts are forward-looking statements that involve risks, uncertainties, assumptions and other factors which, if they do not materialize or prove correct, could cause Harbor BioSciences' actual results to differ materially from historical results or those expressed or implied by such forward-looking statements. Such statements are subject to certain risks and uncertainties inherent in the Company's business, including, but not limited to: the ability to complete preclinical and clinical trials successfully and within specified timelines, if at all; the Company's capital needs; the Company's ability to obtain additional funding; our ability to obtain regulatory approval for Apoptone, Triolex, or any other investigational drug candidate; and other risks detailed from time to time in the Company's filings with the Securities and Exchange Commission. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. Except as required by law, Harbor BioSciences undertakes no obligation to update or revise the information contained in this press release as a result of new information, future events or circumstances arising after the date of this press release.