Biotech Values

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Dew,

Why is SPPI issuing a PR about Satraplatin now? Of what use is this information now? Do the statistics about the correlation between PFS and OS have relevance for other prostate cancer drugs?

http://phx.corporate-ir.net/phoenix.zhtml?c=83249&p=irol-newsArticle&ID=1295063&highlight=




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New Data from Satraplatin Phase 3 Trial in Second-Line Castrate-Refractory Prostate Cancer Presented at 2009 ASCO Annual Meeting
SPARC Trial Analyses Demonstrate Pain At Baseline, Pain Progression And Progression-Free Survival At Three Months Are Predictive Of Overall Survival In Metastatic Castrate-Refractory Prostate Cancer Patients Previously Treated With Docetaxel Data From Several Other Trials Evaluating Satraplatin In Combination With Various Anti-Cancer Therapies Published In ASCO Proceedings
IRVINE, Calif.--(BUSINESS WIRE)--Jun. 2, 2009-- Spectrum Pharmaceuticals, Inc. (NasdaqGM:SPPI), a commercial-stage biotechnology company with two proprietary, FDA-approved oncology drugs on the market, today announced that data from the double-blind, randomized satraplatin Phase 3 trial, the SPARC trial (Satraplatin and Prednisone Against Refractory Cancer) were presented at the 2009 American Society for Clinical Oncology (ASCO) Annual Meeting in Orlando, Florida. The SPARC trial evaluated satraplatin plus prednisone versus placebo plus prednisone in 950 patients with castrate-refractory prostate cancer (CRPC) who had progressed after initial chemotherapy. The data presented are retrospective analyses of the SPARC trial evaluating correlations between overall survival (OS) and pain at baseline, pain progression, and progression-free survival (PFS) at three months.

One presentation (“Use of pain at baseline and pain progression to predict overall survival in patients with docetaxel pretreated metastatic castration-refractory prostate cancer: results from the SPARC trial,” Sartor et al, Abstract #5148), analyzed the docetaxel-pretreated population (n= 488) in two separate ways:

The first analysis compared OS in those patients who had no pain* (Present Pain Intensity (PPI) score < 1) vs. those with pain (PPI > 2) at time of entry to the trial; and
The second analysis compared OS in those patients who experienced pain progression versus progression by pre-specified measures other than pain (as judged by the blinded Independent Review Committee (IRC)).
Shorter OS time was observed in docetaxel-pretreated patients who had pain at baseline compared to those who did not. The median survival of patients with baseline pain (n=178) was 44 weeks versus 72 weeks for patients without baseline pain (n=287) [stratified hazard ratio: 0.59 (95% CI: 0.48-0.74), stratified log-rank p<0.0001]. The IRC found that 414 docetaxel-pretreated patients (84.8%) progressed as of the data cutoff date for the SPARC study. Of these, the median survival of patients showing pain progression (n=196) was 47 weeks, compared to 71 weeks for non-pain progressors (n=292) [stratified hazard ratio: 0.71 (95% CI: 0.57-0.87), stratified log-rank p=0.0022]. Thus, pain at baseline, as well as pain progression, were prognostic indicators of OS in the docetaxel-pretreated patient population.

A second presentation (“Correlation of progression-free survival and overall survival in men with metastatic castration-resistant prostate cancer who failed first-line chemotherapy: results from the SPARC trial,” Halabi et al, Abstract #5150) evaluated whether PFS at three months was predictive of OS and explored the statistical dependencies between PFS and OS. Of the 853 men alive at three months post-randomization, 477 (56%) had already progressed. The median survival for this group was 34.5 weeks versus 78.7 weeks in men who had not progressed at the same three month timepoint. [hazard ratio: 2.16 (95% CI =1.84-2.55), p-value <0.001]. The dependence between PFS and OS was 0.29 (95% confidence limits = 0.24-0.33, p-value < 0.00001). Thus PFS at three months predicts OS. Additional studies will be needed to assess the clinical relevance of the individual components of progression as defined in the SPARC trial to OS.

Data from other Phase I and Phase II clinical trials evaluating satraplatin in combination with other cancer therapeutic drugs were published in the 2009 ASCO Annual Meeting Proceedings.

Phase II trial of bevacizumab and oral satraplatin and prednisone in docetaxel pretreated metastatic castrate resistant prostate cancer – Vaishampayan et al (Abstract #e16028)
Dose finding study of the combination of satraplatin and gemcitabine in patients with advanced solid tumors – Di Paola et al (Abstract #e13534)
A phase I study investigating the combination of orally bioavailable platinum and nonparticle albumin-bound paclitaxel in advanced solid tumors – Deshpande et al (Abstract #e13501)



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