Phase 2 study of the pan-isoform PI3 kinase inhibitor BKM120 in metastatic urothelial carcinoma patients

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Background: PI3 kinase (PI3K) pathway alterations are found in 39% of urothelial carcinoma (UC) (TCGA). Prior reports have shown significant responses in metastatic UC patients (pts) whose tumors harbor PI3K pathway alterations treated with mTOR inhibitors, providing a rationale to investigate BKM120 in mUC. Methods: This phase II study enrolled mUC pts progressing on platinum-based chemotherapy (up to 4 prior agents). The primary and secondary endpoints were proportion of pts progression-free at 2 months and response rate (RR) by Response Criteria in Solid Tumors (RECIST) v1.1, respectively. A Simon 2-stage design was used to discriminate between a 2 month PFS rate of <60% (at which point the trial would be halted) vs. >80%. Pts received 100 mg drug once daily. To identify predictors of response/resistance to BKM120, targeted exon capture sequencing was performed to define the mutation status of PIK3CA, PTEN, AKT1, TSC1, and additional genes within tumors from all treated pts. Results: 13 of 15 enrolled pts were eligible for the primary endpoint. Median age was 65 (53-82). Pts had received an average of 3 agents (2-4) before enrollment. The median progression-free survival (PFS) was 2.77 months (95% CI: 1.83-3.71) with 6 pts displaying stable disease (SD) and 1 partial response (PR) at 2 months (PFS rate 54%). Sequencing identified 2 pts with PIK3CA mutations (E542K, H1047R) who experienced progression as best RECIST response. Tumor from the pt with a 16 month PR harbored a TSC1 R500* nonsense mutation. 1 pt with SD lasting 3.7 months had a TSC1 L330fs truncation. Conclusions: While BKM120 therapy did not display a significant improvement in 2-month PFS rate compared to standard chemotherapy in the second-line setting, 2 pts, one with a durable PR and one with SD, had tumors with inactivating mutations in TSC1. Based upon these results, an expansion cohort is accruing in which select mUC pts whose tumors harbor PI3K pathway alterations receive BKM120. Clinical trial information: NCT01551030.

Gemcitabine-cisplatin (GC) plus radical cystectomy-pelvic lymph node dissection (RC-PLND) for patients (pts) with muscle-invasive bladder cancer (MIBC): Assessing impacts of neoadjuvant chemotherapy (NAC) and the PLND

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Background: NAC and RC-PLND improves survival in MIBC and GC is a standard NAC option. However, little is known about GC efficacy endpoints and the individual contribution of NAC and surgery. Methods: Pts with clinical T2-T4aN0M0 MIBC treated from 1/2000 to 10/2012 with a planned 4 cycles of GC plus RC-PLND within 90 days (D) of NAC were evaluated retrospectively for the number (#) of cycles, dose delivered, D from end of NAC to RC-PLND, margin status, LN status and # of LN identified. Post-NAC pathologic endpoints included complete response (pT0), residual Non-MIBC disease (pTa/Tis/T1;N0) and ≥MIBC disease (≥pT2N0). Associations with overall survival (OS) and disease-free survival were analyzed using Cox regression; non-linear associations with # of resected LN used linear and quadratic terms. Results: 154 pts met inclusion criteria. 5-year (yr) OS was 61% (95% CI 53-71%). Post-NAC pT0 was achieved in 21% (32/154) and Non-MIBC in 25% (39/154 - pTa (2), pTis (25), pT1 (12)). Post-NAC pT0 and Non-MIBC had similar 5-yr OS (85% and 89%, respectively) and combined (<pT2) pts differed significantly from pts with ≥pT2, (87% (95% CI 78, 98%) and 38% (95% CI 27, 53%), respectively; p<0.001). Median D from NAC to RC-PLND was 34 and median # of resected LN was 19. On univariate analysis, # of cycles (4 vs <4), GC dose intensity and total dose, clinical stage (cT2 vs cT3/cT4), # of resected LN, positive (+) LN and + margins were significant for OS. In multivariate analysis, post-NAC pathology ≥pT2 (HR 6.7; 95% CI 2.6-17.4; p<0.001), + LN (HR 3.21; 95% CI 1.6-6.4; p=0.001) and + margins (HR 3.2; 95% CI 1.4-7.5; p=0.007) were significant for increased risk of death. Using a model with these 3 predictors to estimate the benefit of PLND, the hazard ratio decreased with each LN resected until 25 and then plateaued beyond 25 (p=0.016). Conclusions: NAC with GC has excellent drug delivery, permits rapid RC-PLND and achieves meaningful pathologic responses. Survival is similar with <pT2N0 and pT0N0 post NAC pathology. Pts with post NAC ≥pT2, + margins, and + LN do poorly. Increasing LN yield on PLND contributes to OS.

The high incidence of vascular thromboembolic events (VTE) in advanced urothelial cancer (UC) patients (pts) treated with carboplatin (Cb): Analysis of treatment with gemcitabine (G)/cb (GCb), gcb/bevacizumab (GCbBev), or gemcitabine/cisplatin (GCis)

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Background: VTE occur in ~13% of pts receiving Cis-based therapy for UC. Cb-based therapy is considered less thrombogenic but no definitive data exist to support this conclusion. While Bev added to chemotherapy (Ch) increases VTE in other tumors, VTE impact when added to UC Ch is unknown. This study evaluated the incidence of and etiologic factors for VTE in UC pts treated with GCb, GCbBev and GCis. Methods: UC pts treated from 6/2006 to 6/2010 on a GCbBev protocol were analyzed prospectively. Planned therapy was 6 cycles of GCbBev then Bev alone; pts who had ≥ 3 cycles were included. Similar UC pts treated with GCb or GCis during the same time were retrospectively evaluated. Type of VTE and potential contributing clinical factors were collected. VTE was defined as pulmonary embolism, vascular thrombosis, myocardial infarction or cerebral vascular accident. Associations with Ch regimen were tested using Fisher’s exact test or linear regression. Factors associated with VTE were analyzed using conditional logistic regression stratified by Ch regimen. Results: 198 pts were analyzed. VTE occurred in 13/51 (26%) GCbBev pts, 22/92 (24%) GCb pts, and 8/55 (15%) GCis pts. Age (≤65 vs >65; p<0.001), having had a prior cystectomy (p<0.001), mass near pelvic vessels (p=0.027), Khorana risk group (p=0.025) and anti-platelet therapy (p=0.036) were significantly associated with the Ch regimen reflecting cohort-specific differences. Type of Ch was not associated with any VTE (p=0.3) or type of VTE (arterial vs venous) (p=0.11). Having had a prior cystectomy was associated with increased risk of VTE (OR 2.2, 95% CI 1.0-5.0, p=0.047). Conclusions: This is the largest series reporting VTE in Cb-treated UC pts; the VTE rate of 24% (95% CI 17, 32%) is higher than expected. Bev does not appear to increase this risk. VTE in Cis-treated pts (15%) was similar to prior reports. The finding that pts with advanced UC are at high risk of VTE regardless of the specific platinum agent warrants further study of Cb therapy-related risk and analysis for contributing factors including prior pelvic surgery.