Correlation of a novel whole blood RT-PCR assay measuring AR-V7 expression with outcomes in metastatic castration-resistant prostate cancer (mCRPC) patients treated with abiraterone acetate (ABI).
Bibliographic record
Abstract
223 Background: Expression of androgen receptor splice variant 7 (AR-V7) in circulating tumor cells (CTCs) has been associated with resistance to ABI and enzalutamide (ENZ) (Antonarakis et al. N Engl J Med 2014). We have developed a RT-PCR assay that is neither time sensitive nor requires CTC enrichment for detection of prostate cancer (PCa)-associated transcripts in whole blood. Using this assay, our aim was to correlate AR-V7 expression with outcomes on ABI. Methods: 2.5 ml whole blood was collected into PAXgene RNA tubes from mCRPC patients (pts) commencing ABI. RT-PCR was performed for the following genes: AR-V7, FOXA1, GRHL2, HOXB13, KLK2, KLK3 and TMPRSS2:ERG. For each gene, the highest CT value among 20 normal controls was set as the threshold for a positive (+) test. Clinical endpoints were PSA50 response rate (RR) (PSA decline ≥ 50% confirmed ≥ 3 weeks later), PSA30 RR, time to PSA (PCWG2 criteria) or clinical progression (change in anti-cancer therapy or decline in ECOG performance status (PS) ≥ 2 levels due to PCa), and overall survival (OS). Results: Whole blood samples were obtained from 37 pts. Median age was 70. 59% received prior docetaxel. All pts were ABI and ENZ naïve. PSA50 RR was 37% and PSA30 RR was 48%. Median progression-free survival (PFS) was 3.8 months (mos) and median OS was 21.0 mos. 11% (4/37) of pts were AR-V7+. AR-V7+ pts were more likely to have high ALP (P= 0.04; Χ2), high LDH (P= 0.07) and ECOG PS ≥ 2 (P= 0.052). Pts with an AR-V7+ test had lower PSA50 RR (0% vs. 42%, P= 0.10; Χ2) and PSA30 RR (0% vs. 52%, P= 0.051) together with shorter median PFS (0.7 mos vs. 4.0 mos, P< 0.001; log-rank) and median OS (5.5 mos vs. 22.1 mos, P< 0.001). Other factors linked with worse OS were high ALP (P= 0.02), liver metastases (P= 0.03), ≤ 36 mos on primary hormone therapy (P= 0.04), HOXB13+ (P= 0.03) and KLK2+ (P< 0.001). Conclusions: RT-PCR detection of AR-V7 transcripts in whole blood was associated with a 0% PSA RR and significantly inferior PFS and OS in pts treated with ABI. These results reinforce the potential utility of AR-V7 as a prognostic and predictive biomarker for mCRPC. Validation of the assay in larger datasets is ongoing.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".