Abstract A221: A phase II study of SB939 in patients with recurrent or metastatic castration resistant prostate cancer (CRPC).
Bibliographic record
Abstract
Abstract Background: SB939 is a potent oral inhibitor of class I, II and IV histone deacetylases (HDACs) with high tumor tissue selectivity. These 3 classes of HDAC are highly expressed in prostate cancer and associated with poor clinical outcomes. HDAC inhibition has been shown to abrogate androgen receptor signaling via inactivation of HSP90, and may have relevance particularly in TMPRSS2-ERG fusion positive prostate cancer. Methods: In this multicenter phase II study, pts with CRPC received SB939 60mg every other day 3 times per week × 3 weeks on a 28-day cycle. Primary endpoints were PSA response rate (RR) (>50% decline from baseline for > 4 weeks) and progression free survival (PFS). Secondary endpoints included objective response rate; response duration, overall survival; circulating tumor cell (CTC) enumeration at baseline, 6 and 12 weeks; TMPRSS2-ERG fusion analysis; correlative analysis of archival tissue; and safety. Planned sample size was 29 pts, the hypotheses (PSA RR <2% vs. ≥15%) could be tested at 10% and levels. Results: Twenty-nine pts have been accrued. Median age is 69, 25 pts had received no prior chemotherapy, ECOG performance status was 0/1 in 48%/52% of pts. Bone/lymph node/visceral metastases were present in 86%/69%/10% of pts. The median number of cycles of SB939 administered is 2 (range 1–6) with 7 pts still continuing treatment. Adverse events were generally grade 1–2, with 5 patients experiencing grade 3 events (fatigue (5 pts), vomiting (1 pt) and dyspnea (1pt)). To date, a confirmed PSA response has been noted in 2 pts (7%). In 8 RECIST-evaluable pts, there were no objective responses, and 3 pts had stable disease lasting from 3.4 to 5.6 months. CTC favorable conversion (from ≥5 at baseline to <5 at 6 or 12 weeks) was observed in 9/14 evaluable patients (64%) and unfavorable CTC levels (>5) at 6 weeks correlated with PSA progression. RT-PCR for presence of TMPRSS2-ERG transcripts from whole blood and FISH analyzes of CTC and archival tissue for TMPRSS2-ERG fusion and PTEN deletion status are ongoing. Conclusion: SB939 is well tolerated and has shown early evidence of activity in CRPC. Analysis of more mature data will be required to determine whether this agent warrants further study, and whether TMPRSS2-ERG status might predict for response to SB939. Supported by grants from the Canadian Cancer Society and the Ontario Institute for Cancer Research. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A221.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".