Pembrolizumab or placebo with chemoradiotherapy followed by pembrolizumab or placebo for newly diagnosed, high-risk, locally advanced cervical cancer (ENGOT-cx11/GOG-3047/KEYNOTE-A18): a randomised, double-blind, phase 3 clinical trial

BACKGROUND

Pembrolizumab has shown efficacy in persistent, recurrent, or metastatic cervical cancer. The effect of chemoradiotherapy might be enhanced by immunotherapy. In this phase 3 trial, we assessed the efficacy and safety of adding pembrolizumab to chemoradiotherapy in locally advanced cervical cancer.

METHODS

In this randomised, double-blind, placebo-controlled, phase 3 ENGOT-cx11/GOG-3047/KEYNOTE-A18 clinical trial, adults (age ≥18 years) at 176 medical centres in 30 countries with newly diagnosed, high-risk, locally advanced cervical cancer were randomly assigned (1:1) using an interactive voice-response system with integrated web response to receive 5 cycles of pembrolizumab (200 mg) or placebo every 3 weeks plus chemoradiotherapy, followed by 15 cycles of pembrolizumab (400 mg) or placebo every 6 weeks. Randomisation was stratified by planned external beam radiotherapy type (intensity-modulated radiotherapy or volumetric-modulated arc therapy vs non-intensity-modulated radiotherapy or non-volumetric-modulated arc therapy), cervical cancer stage at screening (International Federation of Gynecology and Obstetrics 2014 stage IB2-IIB node positive vs stage III-IVA), and planned total radiotherapy (external beam radiotherapy plus brachytherapy) dose (<70 Gy vs ≥70 Gy equivalent dose in 2 Gy fractions). Primary endpoints were progression-free survival per Response Evaluation Criteria in Solid Tumours version 1.1-by investigator or by histopathologic confirmation of suspected disease progression-and overall survival. Primary analysis was conducted in the intention-to-treat population, which included all randomly allocated participants. Safety was assessed in the as-treated population, which included all randomly allocated patients who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT04221945, and is closed to new participants.

FINDINGS

Between June 9, 2020, and Dec 15, 2022, 1060 participants were randomly assigned to treatment, with 529 assigned to the pembrolizumab-chemoradiotherapy group and 531 to the placebo-chemoradiotherapy group. At data cutoff (Jan 9, 2023), median follow-up was 17·9 months (IQR 11·3-22·3) in both treatment groups. Median progression-free survival was not reached in either group; rates at 24 months were 68% in the pembrolizumab-chemoradiotherapy group versus 57% in the placebo-chemoradiotherapy group. The hazard ratio (HR) for disease progression or death was 0·70 (95% CI 0·55-0·89, p=0·0020), meeting the protocol-specified primary objective. Overall survival at 24 months was 87% in the pembrolizumab-chemoradiotherapy group and 81% in the placebo-chemoradiotherapy group (information fraction 42·9%). The HR for death was 0·73 (0·49-1·07); these data have not crossed the boundary of statistical significance. Grade 3 or higher adverse event rates were 75% in the pembrolizumab-chemoradiotherapy group and 69% in the placebo-chemoradiotherapy group.

INTERPRETATION

Pembrolizumab plus chemoradiotherapy significantly improved progression-free survival in patients with newly diagnosed, high-risk, locally advanced cervical cancer.

FUNDING

Merck Sharp & Dohme, a subsidiary of Merck & Co (MSD).

Pembrolizumab or Placebo Plus Chemotherapy With or Without Bevacizumab for Persistent, Recurrent, or Metastatic Cervical Cancer: Subgroup Analyses From the KEYNOTE-826 Randomized Clinical Trial

Importance

The KEYNOTE-826 randomized clinical trial showed statistically significant and clinically meaningful survival benefits with the addition of pembrolizumab to chemotherapy with or without bevacizumab in patients with persistent, recurrent, or metastatic cervical cancer. Treatment effects in patient subgroups of the study population are unknown.

Objective

To assess efficacy outcomes in patient subgroups of KEYNOTE-826.

Design, Setting, and Participants

Exploratory subgroup analyses were conducted in a global, phase 3, randomized, double-blind, placebo-controlled clinical trial. Participants included women with persistent, recurrent, or metastatic adenocarcinoma, adenosquamous carcinoma, or squamous cell carcinoma of the cervix that had not been treated with systemic chemotherapy and was not amenable to curative treatment. This subanalysis was conducted from November 20, 2018, to May 3, 2021.

Interventions

Pembrolizumab, 200 mg, every 3 weeks or placebo for up to 35 cycles plus chemotherapy (paclitaxel, 175 mg/m2, plus cisplatin, 50 mg/m2, or carboplatin AUC 5 [area under the free carboplatin plasma concentration vs time curve]) with or without bevacizumab, 15 mg/kg.

Main Outcomes and Measures

Overall survival (OS) and progression-free survival (PFS) by investigator assessment per Response Evaluation Criteria in Solid Tumors version 1.1 in subgroups defined by use of bevacizumab (yes or no), choice of platinum (carboplatin or cisplatin), prior chemoradiotherapy (CRT) exposure only (yes or no), and histologic type (squamous or nonsquamous) in patients with programmed cell death ligand 1-positive tumors (defined as a combined positive score [CPS] ≥1) and in the intention-to-treat population.

Results

A total of 617 patients (median age, 51 years; range, 22-82 years) were enrolled in the trial. In the CPS greater than or equal to 1 population, hazard ratios (HRs) for OS favored the pembrolizumab group in all subgroups: with bevacizumab (HR, 0.62; 95% CI, 0.45-0.87) and without bevacizumab (HR, 0.67; 95% CI, 0.47-0.96), use of carboplatin (HR, 0.65; 95% CI, 0.50-0.85) and cisplatin (HR, 0.53; 95% CI, 0.27-1.04), with prior CRT only (HR, 0.56; 95% CI, 0.39-0.81) and without prior CRT only (HR, 0.72; 95% CI, 0.52-1.00), and squamous (HR, 0.60; 95% CI, 0.46-0.79) and nonsquamous (HR, 0.70; 95% CI, 0.41-1.20) histologic type. In the intention-to-treat population, HRs for OS also favored the pembrolizumab group in all subgroups: with bevacizumab (HR, 0.63; 95% CI, 0.47-0.87) and without bevacizumab (HR, 0.74; 95% CI, 0.53-1.04), use of carboplatin (HR, 0.69; 95% CI, 0.54-0.89) or cisplatin (HR, 0.59; 95% CI, 0.32-1.09), with prior CRT only (HR, 0.64; 95% CI, 0.45-0.91) and without prior CRT only (HR, 0.71; 95% CI, 0.53-0.97), and squamous (HR, 0.61; 95% CI, 0.47-0.80) and nonsquamous (HR, 0.76; 95% CI, 0.47-1.23) histologic type. Similar to OS, the addition of pembrolizumab prolonged PFS across all subgroups in the CPS greater than or equal to 1 and intention-to-treat populations.

Conclusions and Relevance

The findings of this trial suggest that adding pembrolizumab to chemotherapy with or without bevacizumab improved OS across subgroups of patients with persistent, recurrent, or metastatic cervical cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT03635567.

First-Line Pembrolizumab + Chemotherapy Versus Placebo + Chemotherapy for Persistent, Recurrent, or Metastatic Cervical Cancer: Final Overall Survival Results of KEYNOTE-826

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.The phase III, double-blind KEYNOTE-826 trial of pembrolizumab 200 mg or placebo once every 3 weeks for up to 35 cycles plus platinum-based chemotherapy, with or without bevacizumab, showed statistically significant survival benefits with the addition of pembrolizumab for patients with persistent, recurrent, or metastatic cervical cancer (primary data cutoff: May 3, 2021). This article reports the protocol-specified final overall survival (OS) results tested in the PD-L1 combined positive score (CPS) ≥1, all-comer, and CPS ≥10 populations. At the final data cutoff (October 3, 2022), the median study follow-up duration was 39.1 months (range, 32.1-46.5 months). In the PD-L1 CPS ≥1 (N = 548), all-comer (N = 617), and CPS ≥10 (N = 317) populations, median OS with pembrolizumab-chemotherapy versus placebo-chemotherapy was 28.6 months versus 16.5 months (hazard ratio [HR] for death, 0.60 [95% CI, 0.49 to 0.74]), 26.4 months versus 16.8 months (HR, 0.63 [95% CI, 0.52 to 0.77]), and 29.6 months versus 17.4 months (HR, 0.58 [95% CI, 0.44 to 0.78]), respectively. The incidence of grade ≥3 adverse events was 82.4% with pembrolizumab-chemotherapy and 75.4% with placebo-chemotherapy. These results show that pembrolizumab plus chemotherapy, with or without bevacizumab, continued to provide clinically meaningful improvements in OS for patients with persistent, recurrent, or metastatic cervical cancer.

Molecular determinants of clinical outcomes of pembrolizumab in recurrent ovarian cancer: Exploratory analysis of KEYNOTE-100

OBJECTIVE

This prespecified exploratory analysis evaluated the association of gene expression signatures, tumor mutational burden (TMB), and multiplex immunohistochemistry (mIHC) tumor microenvironment-associated cell phenotypes with clinical outcomes of pembrolizumab in advanced recurrent ovarian cancer (ROC) from the phase II KEYNOTE-100 study.

METHODS

Pembrolizumab-treated patients with evaluable RNA-sequencing (n = 317), whole exome sequencing (n = 293), or select mIHC (n = 125) data were evaluated. The association between outcomes (objective response rate [ORR], progression-free survival [PFS], and overall survival [OS]) and gene expression signatures (T-cell-inflamed gene expression profile [TcellinfGEP] and 10 non-TcellinfGEP signatures), TMB, and prespecified mIHC cell phenotype densities as continuous variables was evaluated using logistic (ORR) and Cox proportional hazards regression (PFS; OS). One-sided p-values were calculated at prespecified α = 0.05 for TcellinfGEP, TMB, and mIHC cell phenotypes and at α = 0.10 for non-TcellinfGEP signatures; all but TcellinfGEP and TMB were adjusted for multiplicity.

RESULTS

No evidence of associations between ORR and key axes of gene expression was observed. Negative associations were observed between outcomes and TcellinfGEP-adjusted glycolysis (PFS, adjusted-p = 0.019; OS, adjusted-p = 0.085) and hypoxia (PFS, adjusted-p = 0.064) signatures. TMB as a continuous variable was not associated with outcomes (p > 0.05). Positive associations were observed between densities of myeloid cell phenotypes CD11c+ and CD11c+/MHCII-/CD163-/CD68- in the tumor compartment and ORR (adjusted-p = 0.025 and 0.013, respectively).

CONCLUSIONS

This exploratory analysis in advanced ROC did not find evidence for associations between gene expression signatures and outcomes of pembrolizumab. mIHC analysis suggests CD11c+ and CD11c+/MHCII-/CD163-/CD68- phenotypes representing myeloid cell populations may be associated with improved outcomes with pembrolizumab in advanced ROC.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02674061.

Pembrolizumab for Persistent, Recurrent, or Metastatic Cervical Cancer

BACKGROUND

Pembrolizumab has efficacy in programmed death ligand 1 (PD-L1)-positive metastatic or unresectable cervical cancer that has progressed during chemotherapy. We assessed the relative benefit of adding pembrolizumab to chemotherapy with or without bevacizumab.

METHODS

In a double-blind, phase 3 trial, we randomly assigned patients with persistent, recurrent, or metastatic cervical cancer in a 1:1 ratio to receive pembrolizumab (200 mg) or placebo every 3 weeks for up to 35 cycles plus platinum-based chemotherapy and, per investigator discretion, bevacizumab. The dual primary end points were progression-free survival and overall survival, each tested sequentially in patients with a PD-L1 combined positive score of 1 or more, in the intention-to-treat population, and in patients with a PD-L1 combined positive score of 10 or more. The combined positive score is defined as the number of PD-L1-staining cells divided by the total number of viable tumor cells, multiplied by 100. All results are from the protocol-specified first interim analysis.

RESULTS

In 548 patients with a PD-L1 combined positive score of 1 or more, median progression-free survival was 10.4 months in the pembrolizumab group and 8.2 months in the placebo group (hazard ratio for disease progression or death, 0.62; 95% confidence interval [CI], 0.50 to 0.77; P<0.001). In 617 patients in the intention-to-treat population, progression-free survival was 10.4 months and 8.2 months, respectively (hazard ratio, 0.65; 95% CI, 0.53 to 0.79; P<0.001). In 317 patients with a PD-L1 combined positive score of 10 or more, progression-free survival was 10.4 months and 8.1 months, respectively (hazard ratio, 0.58; 95% CI, 0.44 to 0.77; P<0.001). Overall survival at 24 months was 53.0% in the pembrolizumab group and 41.7% in the placebo group (hazard ratio for death, 0.64; 95% CI, 0.50 to 0.81; P<0.001), 50.4% and 40.4% (hazard ratio, 0.67; 95% CI, 0.54 to 0.84; P<0.001), and 54.4% and 44.6% (hazard ratio, 0.61; 95% CI, 0.44 to 0.84; P = 0.001), respectively. The most common grade 3 to 5 adverse events were anemia (30.3% in the pembrolizumab group and 26.9% in the placebo group) and neutropenia (12.4% and 9.7%, respectively).

CONCLUSIONS

Progression-free and overall survival were significantly longer with pembrolizumab than with placebo among patients with persistent, recurrent, or metastatic cervical cancer who were also receiving chemotherapy with or without bevacizumab. (Funded by Merck Sharp and Dohme; KEYNOTE-826 ClinicalTrials.gov number, NCT03635567.).

Impact of PD-L1 and T-cell inflamed gene expression profile on survival in advanced ovarian cancer

OBJECTIVE

Programmed death ligand 1 (PD-L1) expression affects tumor evasion of immune surveillance. The prognostic value and relationship of PD-L1 expression to T-cell-inflamed immune signatures in ovarian cancer are unclear. The purpose of this study is to evaluate the impact of PD-L1 on overall survival and its correlation with an immune-mediated gene expression profile in patients with advanced ovarian cancer.

METHODS

PD-L1 expression in tumor and immune cells was assessed by immunohistochemistry, and PD-L1-positive expression was defined as a combined positive score ≥1; a T-cell-inflamed gene expression profile containing interferon γ response genes was evaluated using extracted RNA from surgical samples. Associations between PD-L1 expression, gene expression profile status, and overall survival were analyzed using the Kaplan-Meier method, log-rank test, and multivariate Cox proportional hazards regression models.

RESULTS

A total of 376 patients with advanced epithelial ovarian, primary peritoneal, or fallopian tube cancer treated by cytoreductive surgery and platinum-based therapy were included. PD-L1-positive expression was observed in 50.5% of patients and associated with more advanced stage (p=0.047), more aggressive histologic subtype (p=0.001), and platinum sensitivity defined by increasing treatment-free interval from first platinum-based chemotherapy to next systemic treatment (p=0.027). PD-L1-positive expression was associated with longer overall survival in multivariate analyses (adjusted HR 0.72, 95% CI 0.56 to 0.93). In subgroup analyses, this association was most pronounced in patients with partially platinum-sensitive disease (treatment-free interval ≥6 to <12 months). T-cell-inflamed gene expression profile status correlated with PD-L1 expression (Spearman, ρ=0.712) but was not an independent predictor of overall survival.

CONCLUSION

PD-L1 expression is associated with longer overall survival among advanced ovarian cancer patients. PD-L1 expression may be an independent prognostic biomarker.

First-line pembrolizumab in cisplatin-ineligible patients with locally advanced and unresectable or metastatic urothelial cancer (KEYNOTE-052): a multicentre, single-arm, phase 2 study

BACKGROUND

More than half of all patients with advanced urothelial cancer cannot receive standard, first-line cisplatin-based chemotherapy because of renal dysfunction, poor performance status, or other comorbidities. We assessed the activity and safety of first-line pembrolizumab in cisplatin-ineligible patients with locally advanced and unresectable or metastatic urothelial cancer.

METHODS

In this multicentre, single-arm, phase 2 study (KEYNOTE-052), cisplatin-ineligible patients with advanced urothelial cancer who had not been previously treated with systemic chemotherapy were recruited from 91 academic medical centres in 20 countries. Enrolled patients received intravenous pembrolizumab 200 mg every 3 weeks. The primary endpoint was objective response (the proportion of patients who achieved complete or partial response) in all patients and by PD-L1 expression status according to the Response Evaluation Criteria in Solid Tumors, version 1.1, as assessed by independent central review. PD-L1 expression was assessed in tumour and inflammatory cells from tumour biopsies provided at study entry. Activity and safety were analysed in all patients who received at least one dose of pembrolizumab (all-patients-treated population). This study is registered with ClinicalTrials.gov, number NCT02335424, and follow-up is ongoing.

FINDINGS

Between Feb 24, 2015, and Aug 8, 2016, 374 patients were enrolled and 370 patients received at least one dose of pembrolizumab. 89 (24%, 95% CI 20-29) of 370 patients had a centrally assessed objective response, and as of Sept 1, 2016 (data cutoff), 74 (83%) of 89 responses were ongoing. Median follow-up was 5 months (IQR 3·0-8·6). A PD-L1-expression cutoff of 10% was associated with a higher frequency of response to pembrolizumab; 42 (38%, 95% CI 29-48) of 110 patients with a combined positive score of 10% or more had a centrally assessed objective response. The most common grade 3 or 4 treatment-related adverse events were fatigue (eight [2%] of 370 patients), alkaline phosphatase increase (five [1%]), colitis, and muscle weakness (both four [1%]). 36 (10%) of 370 patients had a serious treatment-related adverse event. 17 (5%) of 370 patients died from non-treatment-related adverse events associated with death, and one patient died from treatment-related adverse events (myositis in addition to grade 3 thyroiditis, grade 3 hepatitis, grade 3 pneumonia, and grade 4 myocarditis).

INTERPRETATION

First-line pembrolizumab has antitumour activity and acceptable tolerability in cisplatin-ineligible patients with urothelial cancer, most of whom were elderly, had poor prognostic factors, or had serious comorbidities. In view of this result, pembrolizumab has become a new treatment option for patients who are cisplatin-ineligible or not suitable candidates for chemotherapy. Pembrolizumab in the first-line setting is being further assessed in the phase 3 KEYNOTE-361 trial (ClinicalTrials.gov, NCT02335424).

FUNDING

Merck & Co.

Efficacy of the nanoparticle-drug conjugate CRLX101 in combination with bevacizumab in metastatic renal cell carcinoma: results of an investigator-initiated phase I-IIa clinical trial

BACKGROUND

Anti-angiogenic therapies are effective in metastatic renal cell carcinoma (mRCC), but resistance is inevitable. A dual-inhibition strategy focused on hypoxia-inducible factor (HIF) is hypothesized to be active in this refractory setting. CRLX101 is an investigational camptothecin-containing nanoparticle-drug conjugate (NDC), which durably inhibits HIF1α and HIF2α in preclinical models and in gastric cancer patients. Synergy was observed in the preclinical setting when combining this NDC and anti-angiogenic agents, including bevacizumab.

PATIENTS AND METHODS

Patients with refractory mRCC were treated every 2 weeks with bevacizumab (10 mg/kg) and escalating doses of CRLX101 (12, 15 mg/m(2)) in a 3 + 3 phase I design. An expansion cohort of 10 patients was treated at the recommended phase II dose (RP2D). Patients were treated until progressive disease or prohibitive toxicity. Adverse events (AEs) were assessed using CTCAE v4.0 and clinical outcome using RECIST v1.1.

RESULTS

Twenty-two patients were response-evaluable in an investigator-initiated trial at two academic medical centers. RCC histologies included clear cell (n = 12), papillary (n = 5), chromophobe (n = 2), and unclassified (n = 3). Patients received a median of two prior therapies, with at least one prior vascular endothelial tyrosine kinase inhibitor therapy (VEGF-TKI). No dose-limiting toxicities were observed. Grade ≥3 AEs related to CRLX101 included non-infectious cystitis (5 events), fatigue (3 events), anemia (2 events), diarrhea (2 events), dizziness (2 events), and 7 other individual events. Five of 22 patients (23%) achieved partial responses, including 3 of 12 patients with clear cell histology and 2 of 10 patients (20%) with non-clear cell histology. Twelve of 22 patients (55%) achieved progression-free survival (PFS) of >4 months.

CONCLUSIONS

CRLX101 combined with bevacizumab is safe in mRCC. This combination fulfilled the protocol's predefined threshold for further examination with responses and prolonged PFS in a heavily pretreated population. A randomized phase II clinical trial in mRCC of this combination is ongoing.

Evaluating the safety and efficacy of axitinib in the treatment of advanced renal cell carcinoma

Axitinib is a tyrosine kinase inhibitor of vascular endothelial growth factor receptor, platelet-derived growth factor receptor-α, and c-kit. Phase I studies demonstrated 5 mg twice daily as the recommended starting dose with notable effects seen in renal cell carcinoma, an observation confirmed in Phase II trials. The trial of comparative effectivess of axitinib versus sorafenib in advanced renal cell carcinoma (AXIS) was an international randomized Phase III study designed for registration purposes, compared axitinib to sunitinib. This trial randomized 723 patients with metastatic kidney cancer to axitinib or sunitinib in the second-line setting and demonstrated a median progression-free survival of 6.7 months for axitinib versus 4.7 months for sorafenib (P<0.0001). Clinical benefit was detected regardless of prior therapy, but no overall survival benefit has been observed. Axitinib is well tolerated without a significant effect on quality of life. The most common grade 3 toxicities are hypertension (16%), diarrhea (11%), and fatigue (11%), with other notable side effects being anorexia, nausea, hand–foot syndrome, and rash. Patients who developed diastolic blood pressure >90 mmHg were noted to have significantly longer median overall survival and overall response rates when compared to normotensive patients. Therefore, the manufacturer recommends escalating the twice-daily dose to 7 mg and 10 mg, as tolerated, if there is no significant increase in blood pressure on treatment. Currently, axitinib is approved for use in the second-line setting for patients with metastatic renal cell carcinoma. Research is ongoing in other disease settings.

Validation of a coding algorithm to identify bladder cancer and distinguish stage in an electronic medical records database

Studies on outcomes in bladder cancer rely on accurate methods to identify patients with bladder cancer and differentiate bladder cancer stage. Medical record and administrative databases are increasingly used to study cancer incidence, but few have distinguished cancer stage, and none have focused on bladder cancer. In this study, we used data from The UK Health Improvement Network (THIN) to identify patients with bladder cancer using at least one diagnostic code for bladder cancer, and distinguish muscle-invasive from non-invasive disease using a subsequent code for cystectomy. Algorithms were validated against a gold standard of physician-completed questionnaires, pathology reports, and consultant letters. Algorithm performance was evaluated by measuring positive predictive value (PPV) and corresponding 95% confidence interval (CI). Among all patients coded with bladder cancer (n = 194), PPV for any bladder cancer was 99.5% (95% CI, 97.2-99.9). PPV for incident bladder cancer was 93.8% (95% CI, 89.4-96.7). PPV for muscle-invasive bladder cancer was 70.1% (95% CI, 59.4-79.5) in patients with cystectomy (n = 95) and 83.9% (95% CI, 66.3-94.5) in those with cystectomy plus additional codes for metastases and death (n = 31). Using our codes for bladder cancer, the age- and sex-standardized incidence rate (SIR) of bladder cancer in THIN approximated that measured by cancer registries (SIR within 20%), suggesting that sensitivity was high as well. THIN is a valid and novel database for the study of bladder cancer. Our algorithm can be used to examine the epidemiology of muscle-invasive bladder cancer or outcomes following cystectomy for patients with muscle invasion.

Incidence of bladder cancer in patients with type 2 diabetes treated with metformin or sulfonylureas

OBJECTIVE

Previous studies evaluating the effect of metformin on cancer risk have been impacted by time-related biases. To avoid these biases, we examined the incidence of bladder cancer in new users of metformin and sulfonylureas (SUs).

RESEARCH DESIGN AND METHODS

This cohort study included 87,600 patients with type 2 diabetes in The Health Improvement Network database. Use of metformin or an SU was treated as a time-dependent variable. Cox regression-generated hazard ratios (HRs) compared metformin use with SU use, adjusted for age, sex, smoking, obesity, and HbA1c level.

RESULTS

We identified 196 incident bladder cancers in the metformin cohort and 66 cancers in the SU cohort. Use of metformin was not associated with decreased bladder cancer risk (HR 0.81 [95% CI 0.60-1.09]). This association did not differ by sex (P for interaction = 0.20). We observed no association with duration of metformin relative to SU use (3 to <4 years of use: 0.57 [0.25-1.34]; 4 to <5 years of use: 0.93 [0.30-2.85; ≥5 years of use: 1.18 [0.44-3.19]; P for trend = 0.26).

CONCLUSIONS

Use of metformin is not associated with a decreased incidence of bladder cancer. Similar methods should be used to study other cancers that have previously been identified as potentially preventable with metformin.

Application of a telomerase-based circulating tumor cell (CTC) assay in bladder cancer patients receiving postoperative radiation therapy: a case study

BACKGROUND

Muscle invasive bladder carcinoma is an often lethal disease that requires aggressive treatment. Improved assays would contribute to better risk prediction and clinical management of this disease. A telomerase-based assay to detect circulating tumor cells (CTCs) may usefully fulfill this role.

METHODS

Two patients (C1 and C2) were enrolled onto an IRB-approved bladder biomarker study before initiating post-operative radiation therapy (RT) for muscle invasive bladder carcinoma. Blood samples were taken at predefined intervals: before, during, and after RT and then retrospectively correlated with imaging studies and disease course.

RESULTS

C1 began RT for positive resection margins on surgical pathology, at which time CTCs were undetectable and pelvic imaging demonstrated no evidence of disease. However, following the completion of treatment, the patient's CTC count was found to have increased to 202 CTCs/mL, and MRI demonstrated new abdominal and pelvic masses consistent with progressive disease. C1 ultimately died of disease with distant and local failure. Conversely, C2 was found to have 632 CTCs/mL before the initiation of RT for positive surgical margins, although imaging demonstrated no visible masses. At the conclusion of RT, repeat imaging showed changes that were indeterminate for either tumor recurrence or post-radiation effects. However, the patient's CTC count had dropped to 184 CTCs/mL. Furthermore, a second follow-up assay performed 6 months later revealed no detectable CTCs and repeat imaging showed complete resolution of worrisome imaging changes, thus excluding tumor progression.

CONCLUSIONS

To our knowledge this is the first report of a telomerase-based assay to identify CTCs in bladder cancer patients. Further studies are required to fully determine the ultimate clinical utility of this assay. However, the two patient vignettes described here illustrate how serial CTC assays may track the disease course and inform the management of bladder cancer patients undergoing adjuvant RT and potentially chemotherapy.

Occult pelvic lymph node involvement in bladder cancer: implications for definitive radiation

PURPOSE

To inform radiation treatment planning for clinically staged, node-negative bladder cancer patients by identifying clinical factors associated with the presence and location of occult pathologic pelvic lymph nodes.

METHODS AND MATERIALS

The records of patients with clinically staged T1-T4N0 urothelial carcinoma of the bladder undergoing radical cystectomy and pelvic lymphadenectomy at a single institution were reviewed. Logistic regression was used to evaluate associations between preoperative clinical variables and occult pathologic pelvic or common iliac lymph nodes. Percentages of patient with involved lymph node regions entirely encompassed within whole bladder (perivesicular nodal region), small pelvic (perivesicular, obturator, internal iliac, and external iliac nodal regions), and extended pelvic clinical target volume (CTV) (small pelvic CTV plus common iliac regions) were calculated.

RESULTS

Among 315 eligible patients, 81 (26%) were found to have involved pelvic lymph nodes at the time of surgery, with 38 (12%) having involved common iliac lymph nodes. Risk of occult pathologically involved lymph nodes did not vary with clinical T stage. On multivariate analysis, the presence of lymphovascular invasion (LVI) on preoperative biopsy was significantly associated with occult pelvic nodal involvement (odds ratio 3.740, 95% confidence interval 1.865-7.499, P<.001) and marginally associated with occult common iliac nodal involvement (odds ratio 2.307, 95% confidence interval 0.978-5.441, P=.056). The percentages of patients with involved lymph node regions entirely encompassed by whole bladder, small pelvic, and extended pelvic CTVs varied with clinical risk factors, ranging from 85.4%, 95.1%, and 100% in non-muscle-invasive patients to 44.7%, 71.1%, and 94.8% in patients with muscle-invasive disease and biopsy LVI.

CONCLUSIONS

Occult pelvic lymph node rates are substantial for all clinical subgroups, especially patients with LVI on biopsy. Extended coverage of pelvic lymph nodes up to the level of the common iliac nodes may be warranted in subsets of patients.

Abstract PR09: Synergistic activity of CRLX101, a nanopharmaceutical in Phase II clinical trials, with antiangiogenic therapies mediated through HIF-1alpha inhibition: A translational research program

Background: Antiangiogenic drugs reduce blood flow to tumors and thereby inhibit tumor growth by starving tumors of oxygen and nutrients. However, antiangiogenic drugs have achieved limited success as monotherapies, in part because of their induction of hypoxia and the concomitant up-regulation of hypoxia-inducible factor 1α (HIF-1α), now well implicated in the promotion of tumor angiogenesis, invasion, metastasis, and cancer stem cell formation. We describe here a translational research program to investigate whether the efficacy of antiangiogenic drugs can be improved through combination with CRLX101, a camptothecin (CPT) containing nanopharmaceutical that inhibits both topoisomerase-1 and HIF-1α.

Material and methods: We will present preclinical and clinical projects conducted across several major research institutions intended to demonstrate the anti-HIF-1α activity of CRLX101, the capacity of this drug to block the epithelial-mesenchymal transition (EMT) and the formation of cancer stem cells, and the synergistic activity of CRLX101 given in combination with antiangiogenic drugs. We will further describe two ongoing clinical trials evaluating these hypotheses, one at the University of Pennsylvania in advanced renal cell carcinoma (RCC) and one at the Massachusetts General Hospital in relapsed ovarian cancer following progression through prior platinum-containing chemotherapy.

Results: A single dose of CRLX101 durably inhibits HIF-1α protein levels across multiple tumor types. Evaluation of CRLX101 in combination with bevacizumab, aflibercept or pazopanib in the A2780 ovarian xenograft tumor model demonstrates synergistic inhibition of tumor growth inhibition as well as increases in the rate of long-term survivorship. While all three antiangiogenic drugs alone increased HIF-1α protein levels, levels were inhibited in response to combination with CRLX101. In clinical evaluations, a CRLX101-bevacizumab combination appears safe and well tolerated with no dose limiting toxicities observed to date. Notable tumor decreases and long periods of progression free survival have been noted among patients treated with CRLX101-based mono and combination therapy.

Conclusions: Results generated through this translational research program suggest that CRLX101 can overcome HIF-1α-mediated acquired resistance to antiangiogenic drugs, supporting the use of CRLX101 in combination with antiangiogenic drugs as an exciting new paradigm for the treatment of cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):PR09.

Citation Format: Scott Eliasof, Sarah Conley, Stephen M. Keefe, Robert Kerbel, Carolyn N. Krasner, Douglas Lazarus, Christian Peters, Elizabeth Pham, Max S. Wicha, Edward G. Garmey. Synergistic activity of CRLX101, a nanopharmaceutical in Phase II clinical trials, with antiangiogenic therapies mediated through HIF-1alpha inhibition: A translational research program. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr PR09.

Abstract 2419: A phase Ib-IIa study evaluating the nanopharmaceutical CRLX101 in combination with bevacizumab in the treatment of patients (pts.) with advanced renal cell carcinoma

Background:

Topoisomerase-1 (topo-1)-inhibiting agents demonstrate activity across multiple cancer types but use of these agents remains limited by insufficient tumor exposure and toxicity. CRLX101, a novel cyclodextrin-containing polymer conjugate of camptothecin (CPT) that self-assembles into nanoparticles, delivers sustained levels of active CPT into cancer cells while substantially reducing systemic exposure. In vitro and in vivo data suggest superior activity of CRLX101 compared to approved agents in multiple animal tumor models. A monotherapy maximum tolerated dose (MTD)/recommended phase 2 dose (RP2D) of 15 mg/m2 IV every 2 weeks (wks.) was reported previously and over 100 cancer pts. have now been treated with CRLX101 across three ongoing phase 2 clinical trials. To be presented separately at this conference, CRLX101 further appears to inhibit HIF1α, a hypoxia-induced transcription factor implicated in tumor angiogenesis, invasion, and metastasis. We hypothesize that observed synergistic activity between CRLX101 and the VEGF-inhibiting monoclonal antibody bevacizumab occurs as a result of overcoming HIF-mediated resistance to VEGF-inhibition. Clear cell renal cell carcinoma (ccRCC), accounting for approximately 85% of RCC, provides an ideal clinical setting in which to evaluate the potential of this drug-drug combination. The most commonly observed genetic abnormality in ccRCC results in higher intracellular levels of HIF1α. Bevacizumab was chosen as a combination partner here because of its proven activity in the treatment of RCC as well as a history of successful combination with chemotherapy partners including topo-1 inhibitors.

Methods:

This clinical trial examines the combination of bevacizumab and CRLX101 in the treatment of pts. with advanced metastatic RCC. The primary objective is to determine the RP2D of CRLX101 administered in ombination with bevacizumab. In a preliminary stage 1b, a standard 3+3 dose-escalation design is being employed and no fewer than 6 pts. will be evaluated at the MTD. A secondary objective is to evaluate progression-free survival (PFS). Based on a preliminary test for futility, the study will be terminated if ≤ 3 of the initial 12 pts. survive without progression to 16 wks. Otherwise, an additional 10 pts. will be enrolled for a total of 22 pts. and the combination will be viewed as active and worthy of further examination if the PFS rate at 16 wks. is ≥ 50%. Additional exploratory endpoints include a comparison of bone marrow histology and molecular features among pts. treated with 12 mg/m2 vs. 15 mg/m2 of CRLX101. Finally, tumor expression of CAIX, a well-studied surrogate for HIF1α activity, will be measured using 124I-cG250, a CAIX antibody, with real-time PET imaging employed to determine the degree of CRLX101-mediated HIF1α modulation.

Citation Format: Stephen M. Keefe, Roger B. Cohen, Scott Eliasof, Edward G. Garmey, Meliessa Hennessy, Kristine M. Mykulowicz, Daniel A. Pryma, Naomi Haas. A phase Ib-IIa study evaluating the nanopharmaceutical CRLX101 in combination with bevacizumab in the treatment of patients (pts.) with advanced renal cell carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2419. doi:10.1158/1538-7445.AM2013-2419

Targeting vascular endothelial growth factor receptor in thyroid cancer: the intracellular and extracellular implications

Our understanding of the molecular pathophysiology of differentiated thyroid cancer (DTC) has developed considerably over the last 10 years. Aberrant signaling through B-Raf and Akt has been implicated in the tumorigenesis of DTC. Moreover, these highly vascular tumors have proven to be sensitive to the inhibition of vascular endothelial growth factor receptor (VEGFR-2). It is likely that the multikinase inhibitors, sorafenib, sunitinib, axitinib, and motesanib, whose targets include VEGFR-2, exert their effects primarily through inhibition of endothelial cells. However, as VEGFR-2 is expressed on DTC cells, these compounds may have direct antitumor action. This review will discuss the key signaling pathways involved in thyroid cancer and their implications for targeted therapy.