Ofranergene Obadenovec (Ofra-Vec, VB-111) With Weekly Paclitaxel for Platinum-Resistant Ovarian Cancer: Randomized Controlled Phase III Trial (OVAL Study/GOG 3018)

PURPOSE

To evaluate the addition of ofranergene obadenovec (ofra-vec, VB-111), a novel gene-based anticancer targeted therapy, to once a week paclitaxel in patients with recurrent platinum-resistant ovarian cancer (PROC).

METHODS

This placebo-controlled, double-blind, phase III trial (ClinicalTrials.gov identifier: NCT03398655) randomly assigned patients with PROC 1:1 to receive intravenous ofra-vec every 8 weeks with once a week IV paclitaxel or placebo with paclitaxel until disease progression. The dual primary end points were overall survival (OS) and progression-free survival (PFS) as assessed by Blinded Independent Central Review.

RESULTS

Between December 2017 and March 2022, 409 patients were randomly assigned. The median PFS was 5.29 months in the ofra-vec arm and 5.36 months in the control arm, hazard ratio (HR) 1.03 (CI, 0.83 to 1.29; P = .7823). The median OS with ofra-vec was 13.37 months versus 13.14 months, HR 0.97 (CI, 0.75 to 1.27; P = .8440). Objective response rates (ORRs) per RECIST 1.1 were similar in both arms: 28.9% with ofra-vec versus 29.6% with control. In both treatment arms, response to CA-125 was a substantial prognostic factor for both PFS and OS. In the ofra-vec arm, the HR in CA-125 responders compared with that in nonresponders for PFS was 0.2428 (CI, 0.1642 to 0.3588), and for OS, the HR was 0.3343 (CI, 0.2134 to 0.5238). Safety profile was characterized by common transient flu-like symptoms such as fever and chills.

CONCLUSION

The addition of ofra-vec to paclitaxel did not improve PFS or OS. The PFS and ORR in the control arm exceeded the results that were anticipated on the basis of the AURELIA chemotherapy control arm. CA-125 response was a substantial prognostic biomarker for PFS and OS in patients with PROC treated with paclitaxel.

Depth of Radiographic Response and Time to Tumor Regrowth Predicts Overall Survival Following Anti-VEGF Therapy in Recurrent Glioblastoma

PURPOSE

Antiangiogenic therapies are known to cause high radiographic response rates due to reduction in vascular permeability resulting in a lower degree of contrast extravasation. In this study, we investigate the prognostic ability for model-derived parameters describing enhancing tumor volumetric dynamics to predict survival in recurrent glioblastoma treated with antiangiogenic therapy.

EXPERIMENTAL DESIGN

N = 276 patients in two phase II trials were used as training data, including bevacizumab ± irinotecan (NCT00345163) and cabozantinib (NCT00704288), and N = 74 patients in the bevacizumab arm of a phase III trial (NCT02511405) were used for validation. Enhancing volumes were estimated using T1 subtraction maps, and a biexponential model was used to estimate regrowth (g) and regression (d) rates, time to tumor regrowth (TTG), and the depth of response (DpR). Response characteristics were compared to diffusion MR phenotypes previously shown to predict survival.

RESULTS

Optimized thresholds occurred at g = 0.07 months-1 (phase II: HR = 0.2579, P = 5 × 10-20; phase III: HR = 0.2197, P = 5 × 10-5); d = 0.11 months-1 (HR = 0.3365, P < 0.0001; HR = 0.3675, P = 0.0113); TTG = 3.8 months (HR = 0.2702, P = 6 × 10-17; HR = 0.2061, P = 2 × 10-5); and DpR = 11.3% (HR = 0.6326, P = 0.0028; HR = 0.4785, P = 0.0206). Multivariable Cox regression controlling for age and baseline tumor volume confirmed these factors as significant predictors of survival. Patients with a favorable pretreatment diffusion MRI phenotype had a significantly longer TTG and slower regrowth.

CONCLUSIONS

Recurrent glioblastoma patients with a large, durable radiographic response to antiangiogenic agents have significantly longer survival. This information is useful for interpreting activity of antiangiogenic agents in recurrent glioblastoma.

A study of neo-adjuvant and adjuvant ofra-vec (VB-111) for treatment of surgically accessible recurrent GBM

TPS2075

Background: Ofranergene obadenovec (ofra-vec, VB-111) is an anti-cancer gene based immune activator and targeted vascular disruptor. The dual mechanism of action triggers a broad antiangiogenic effect and induces of a tumor directed immune response. A previous study demonstrated a survival benefit for patients with recurrent glioblastoma (rGBM) treated with ofra-vec monotherapy, that was continued after progression in combination with bevacizumab. Glioblastoma is an immunologically “cold” microenvironment which fosters immunosuppression and antagonizes anti-tumor immune responses. The role of T-cell infiltration in combating cancer has been increasingly recognized and associated with improved participant outcomes. Based on these observations, this study will assess the hypothesis that neoadjuvant use of ofra-vec will lead to a statistically significant increase in tumor infiltrating T lymphocyte (TIL) density within the tumor and enhanced systemic tumor-specific T cell responses. Methods: Study NCT04406272 is a multicenter, randomized, blinded, placebo-controlled, phase 2 surgical trial to evaluate early immunologic pharmacodynamic parameters for the viral cancer therapy ofra-vec in rGBM. 45 participants with rGBM indicated for resection will randomized to one of three treatment arms: Neoadjuvant Arm: intravenous ofra-vec prior to resection, and ofra-vec every 6 weeks after resection. Adjuvant Arm: placebo prior to resection, and ofra-vec every 6 weeks afterwards. The control arm will receive placebo prior to resection followed by standard of care. Upon evidence of contrast-enhancing progression, bevacizumab may be initiated as needed for supportive care; however, ofra-vec will continue until progression is supported at two consecutive time points. Tumor samples will be obtained and archived at the time of surgery, and blood samples will be obtained as pharmacodynamic markers throughout the study to allow DNA sequencing of T cells. The primary endpoint is to evaluate the influence of neoadjuvant ofra-vec on TIL density. Other endpoints include safety and tolerability, peripheral T cell response, 6mPFS and OS. Study is open for enrolment. Clinical trial information: NCT04406272.

Pivotal study of ofra-vec (VB-111) combined with paclitaxel versus paclitaxel for treatment of platinum-resistant ovarian cancer (OVAL, VB-111-701/GOG-3018)

TPS5606

Background: Ofranergene obadenovec (Ofra-vec, VB-111) is an anti-cancer gene based immune activator and targeted vascular disruptor. The dual mechanism of action triggers a broad antiangiogenic effect and induces of a tumor directed immune response. A phase II trial in patients with platinum resistant ovarian cancer (PROC) demonstrated that ofra-vec in combination with weekly paclitaxel was well tolerated and associated with a CA-125 Objective Response Rate (ORR) of 58%, a trend for improved survival and induction of an immunotherapeutic effect of tumor infiltration with CD-8 T cells. Based on these observations, a pivotal phase III study was initiated in collaboration with the GOG Foundation, Inc. Methods: Study NCT03398655 is an international, randomized, double-blind, placebo-controlled, phase III study. Eligible patients have recurrent PROC and may have been previously treated with up to 5 prior lines of therapy (but not >2 for PROC). Patient are randomized 1:1 to receive ofra-vec (1x1013 Viral Particles) with weekly paclitaxel (80mg/m2), or weekly paclitaxel with placebo. Randomization is stratified by number of prior treatment lines, prior antiangiogenic therapy and platinum refractory disease status. The dual primary endpoints are OS and PFS. A pre-planned interim analysis of CA-125 response (GCIG) performed by the DSMC met the pre-defined criteria showing that CA-125 ORR in the treatment arm was at least 10% higher than in the control arm. Study is enrolling in the US, EU, Japan and Israel, with 90% enrollment to date. Completion of accrual is anticipated in Q1 2022. Clinical trial information: NCT03398655.

Validation of diffusion MRI as a biomarker for efficacy using randomized phase III trial of bevacizumab with or without VB-111 in recurrent glioblastoma

Background

Evidence from single and multicenter phase II trials have suggested diffusion MRI is a predictive imaging biomarker for survival benefit in recurrent glioblastoma (rGBM) treated with anti-VEGF therapy. The current study confirms these findings in a large, randomized phase III clinical trial.

Methods

Patients with rGBM were enrolled in a phase III randomized (1:1), controlled trial (NCT02511405) to compare the efficacy and safety of bevacizumab (BV) versus BV in combination with ofranergene obadenovec (BV+VB-111), an anti-cancer viral therapy. In 170 patients with diffusion MRI available, pretreatment enhancing tumor volume and ADC histogram analysis were used to phenotype patients as having high (>1.24 µm²/ms) or low (<1.24 µm²/ms) ADC_L, the mean value of the lower peak of the ADC histogram, within the contrast enhancing tumor.

Results

Baseline tumor volume (P = .3460) and ADC_L (P = .2143) did not differ between treatment arms. Univariate analysis showed patients with high ADC_L had a significant survival advantage in all patients (P = .0006), as well as BV (P = .0159) and BV+VB-111 individually (P = .0262). Multivariable Cox regression accounting for treatment arm, age, baseline tumor volume, and ADC_L identified continuous measures of tumor volume (P < .0001; HR = 1.0212) and ADC_L phenotypes (P = .0012; HR = 0.5574) as independent predictors of OS.

Conclusion

Baseline diffusion MRI and tumor volume are independent imaging biomarkers of OS in rGBM treated with BV or BV+VB-111.

Clinical trial in progress: Pivotal study of VB-111 combined with paclitaxel versus paclitaxel for treatment of platinum-resistant ovarian cancer (OVAL, VB-111-701/GOG-3018)

TPS5599

Background: Ofranergene obadenovec (VB-111) is a targeted anti-cancer gene therapy with a dual mechanism of action that includes a broad antiangiogenic effect and induction of a tumor directed immune response. A phase II trial in patients with platinum resistant ovarian cancer showed that VB-111 in combination with weekly paclitaxel was well tolerated and associated with a CA-125 Objective Response Rate (ORR) of 58% with a trend for improved survival. The favorable outcomes were associated with induction of an immunotherapeutic effect of tumor infiltration with CD-8 T cells. Based on these observations, a phase III study was initiated in collaboration with the GOG Foundation, Inc. Methods: Study NCT03398655 is an international, randomized, double-blind, placebo-controlled, phase III study. Eligible patients have recurrent platinum-resistant epithelial ovarian cancer with measurable disease (RECIST 1.1), and may have been previously treated with up to 5 prior lines of therapy. Patient are randomized 1:1 to receive VB-111 (1x1013 VPs) with weekly paclitaxel (80mg/m2), or weekly paclitaxel with placebo. Randomization is stratified by number of prior treatment lines, prior antiangiogenic therapy and platinum refractory disease status. The efficacy endpoints are OS, PFS and ORR by RECIST 1.1 and by CA-125 (GCIG criteria). A pre-planned interim analysis was performed by the DSMC in the first 60 patients evaluable for CA-125 response. The analysis met the pre-defined criteria of a CA-125 ORR (GCIG) in the treatment arm at least 10% higher than in the control arm. Study enrolment is ongoing and over 220 patients were enrolled in the US, EU, and Israel. Enrolment of the full sample size of 400 patients is expected to complete by the end of 2021. Clinical trial information: NCT03398655.

A randomized controlled phase III study of VB-111 combined with bevacizumab vs bevacizumab monotherapy in patients with recurrent glioblastoma (GLOBE)

Background

Ofranergene obadenovec (VB-111) is an anticancer viral therapy that demonstrated in a phase II study a survival benefit for patients with recurrent glioblastoma (rGBM) who were primed with VB-111 monotherapy that was continued after progression with concomitant bevacizumab.

Methods

This pivotal phase III randomized, controlled trial compared the efficacy and safety of upfront combination of VB-111 and bevacizumab versus bevacizumab monotherapy. Patients were randomized 1:1 to receive VB-111 10¹³ viral particles every 8 weeks in combination with bevacizumab 10 mg/kg every 2 weeks (combination arm) or bevacizumab monotherapy (control arm). The primary endpoint was overall survival (OS), and secondary endpoints were objective response rate (ORR) by Response Assessment in Neuro-Oncology (RANO) criteria and progression-free survival (PFS).

Results

Enrolled were 256 patients at 57 sites. Median exposure to VB-111 was 4 months. The study did not meet its primary or secondary goals. Median OS was 6.8 versus 7.9 months in the combination versus control arm (hazard ratio, 1.20; 95% CI: 0.91–1.59; P = 0.19) and ORR was 27.3% versus 21.9% (P = 0.26). A higher rate of grades 3–5 adverse events was reported in the combination arm (67% vs 40%), mainly attributed to a higher rate of CNS and flu-like/fever events. Trends for improved survival with combination treatment were seen in the subgroup of patients with smaller tumors and in patients who had a posttreatment febrile reaction.

Conclusions

In this study, upfront concomitant administration of VB-111 and bevacizumab failed to improve outcomes in rGBM. Change of treatment regimen, with the lack of VB-111 monotherapy priming, may explain the differences from the favorable phase II results.

Clinical trials registration

NCT02511405

Utilizing an interim futility analysis of the OVAL study (VB-111-701/GOG 3018) for potential reduction of risk: A phase III, double blind, randomized controlled trial of ofranergene obadenovec (VB-111) and weekly paclitaxel in patients with platinum resistant ovarian cancer

OBJECTIVE

Report the results from a preplanned interim analysis of a phase III, double blind, randomized controlled study of ofranergene obadenovec (VB-111), a targeted anti-cancer gene therapy, in combination with paclitaxel in patients with platinum resistant ovarian cancer (PROC).

METHODS

The OVAL (NCT03398655) study is an on-going study where patients are randomly assigned in a 1:1 ratio to weekly paclitaxel 80 mg/m² with VB-111 or placebo. The protocol specifies a pre-planned unblinded futility interim analysis of CA-125 response per GCIG criteria in the first 60 evaluable patients. The futility rule determined for this analysis was that the response rate of VB-111 must be greater than the response rate of placebo by at least 10% in order to continue the study. Coincident with the interim analysis, the blinded CA-125 response rate was estimated as a proportion of the first 60 evaluable patients with CA-125 response per GCIG criteria. Post-treatment fever is provided as a possible surrogate marker of VB-111 therapy activity.

RESULTS

The median age of the evaluable patients was 62 years (range 41-82); 97% had high-grade serous cancer; 58% had been treated with 3 or more previous lines of therapy, 70% received prior anti-angiogenic treatment, 43% received prior PARP inhibitors. CA-125 response in the VB-111 and weekly paclitaxel treated arm met the pre-specified interim criterion of an absolute advantage of 10% or higher compared to the control. Blinded results show a 53% CA-125 response rate (32/60) with 15% complete response (n=9). Assuming balanced randomization and an absolute advantage of 10% or higher to the VB-111 arm, it may be deducted that the response in the VB-111 treatment arm is 58% or higher. Among patients with post-treatment fever, the CA-125 response rate was 69%.

CONCLUSIONS

At the time of the interim analysis, response rate findings are comparable to the responses seen in a similar patient population in the phase I/II study. The independent data and safety monitoring committee (iDSMC) recommended continuing the OVAL trial as planned. No new safety signals were identified.

NIMG-17. VALIDATION OF DIFFUSION MRI AS AN IMAGING BIOMARKER FOR BEVACIZUMAB THERAPY IN RECURRENT GLIOBLASTOMA IN A RANDOMIZED PHASE III TRIAL OF BEVACIZUMAB WITH OR WITHOUT VB-111 (GLOBE)

BACKGROUND

Evidence from independent single center as well as multicenter phase II trials have suggested diffusion MRI is a strong predictive imaging biomarker for survival benefit in recurrent glioblastoma (rGBM) treated with anti-VEGF monotherapy, but not systemic chemotherapies or combination therapies with anti-VEGF agents. The current study builds on this body of evidence by evaluating these diffusion MR phenotypes in a large randomized phase III clinical trial.

METHODS

Patients with rGBM were enrolled in a phase III randomized (1:1), controlled trial (NCT02511405) to compare the efficacy and safety of bevacizumab (BV) versus bevacizumab in combination with ofranergene obadenovec (BV+VB-111), an anti-cancer viral therapy. In 170 patients with diffusion MRI available, pre-treatment enhancing tumor volume and ADC histogram analysis were used to phenotype patients as having high (&gt;1.24 um2/ms) or low (&lt; 1.24 um2/ms) ADCL, the mean value of the lower peak in a double Gaussian model of the ADC histogram within the contrast enhancing tumor.

RESULTS

Baseline tumor volume (P=0.3460) and ADCL (P=0.2143) did not differ between treatment arms. Univariate analysis showed that patients with high ADCL had a significant survival advantage when pooling all patients (P=0.0006), as well as when examining the BV (P=0.0159) and BV+VB-111 individually (P=0.0262). Multivariable Cox regression accounting for treatment arm, age, baseline tumor volume and ADCL identified continuous measures of tumor volume (P&lt; 0.0001; HR=1.0212) and ADCL phenotypes (P=0.0012; HR=0.5574) as independent predictors of OS.

CONCLUSION

Baseline diffusion MRI and tumor volume are independent imaging biomarkers of OS in rGBM treated with BV or BV+VB-111. Since ADCL was predictive of OS in combination BV+VB-111, results support the working hypothesis that co-administration of VB-111 with BV may block any VB-111 anti-tumor effect, whereas VB-111 monotherapy or priming may result in higher efficacy of VB-111.

Clinical trial in progress: Pivotal study of VB-111 combined with paclitaxel versus paclitaxel for treatment of platinum-resistant ovarian cancer (OVAL, VB-111-701/GOG-3018)

TPS6097

Background: Ofranergene obadenovec (VB-111) is a targeted anti-cancer gene therapy with a dual mechanism: a broad antiangiogenic effect and induction of a tumor directed viral immune response. In a phase II trial in platinum resistant ovarian cancer VB-111 in combination with weekly paclitaxel showed a CA-125 response rate (RR) of 58% and median overall survival (OS) of 498 days compared to 172.5 days in the sub-therapeutic dose (p = 0.028). The combination treatment was well tolerated. Favorable outcomes were associated with induction of an immunotherapeutic effect of tumor infiltration with CD-8 T cells. Based on these observations, a phase III randomized controlled trial, VB-111-701/GOG-3018 (OVAL) was initiated in collaboration with the GOG Foundation, Inc. Methods: The OVAL study, NCT03398655, is an international, randomized, double-blind, placebo-controlled, phase III study. Patients with recurrent platinum-resistant epithelial ovarian cancer, who have measurable disease (RECIST 1.1) and were previously treated with up to 5 lines are randomized 1:1 to receive VB-111 (1x1013 VPs) with weekly paclitaxel (80mg/m2), or weekly paclitaxel with placebo. Randomization is stratified by number of prior treatment lines, prior antiangiogenic therapy and platinum refractory disease status. Treatment beyond asymptomatic RECIST progression may continue until progression is confirmed by follow up imaging. The primary endpoints are OS, safety and tolerability. Secondary endpoints include progression free survival, and objective RR by CA-125 (per GCIG criteria) and RECIST 1.1. The sample size calculation of 400 patients (event driven) provides 92% power to detect a difference in survival at the two-sided 5% significance level using the logrank test. A pre-planned interim analysis will take place in Q1 2020 to assess whether the CA-125 RR per GCIG criteria in the treatment arm is sufficiently larger than in the control arm and is comparable to the positive results of the phase II study. Study enrolment is ongoing and over 80 patients were enrolled in the US and Israel. Enrollment expansion to Europe is planned in 2020. Clinical trial information: NCT03398655.

Safety and efficacy of VB-111, an anticancer gene therapy, in patients with recurrent glioblastoma: results of a phase I/II study

BACKGROUND

VB-111 is a non-replicating adenovirus carrying a Fas-chimera transgene, leading to targeted apoptosis of tumor vascular endothelium and induction of a tumor-specific immune response. This phase I/II study evaluated the safety, tolerability, and efficacy of VB-111 with and without bevacizumab in recurrent glioblastoma (rGBM).

METHODS

Patients with rGBM (n = 72) received VB-111 in 4 treatment groups: subtherapeutic (VB-111 dose escalation), limited exposure (LE; VB-111 monotherapy until progression), primed combination (VB-111 monotherapy continued upon progression with combination of bevacizumab), and unprimed combination (upfront combination of VB-111 and bevacizumab). The primary endpoint was median overall survival (OS). Secondary endpoints were safety, overall response rate, and progression-free survival (PFS).

RESULTS

VB-111 was well tolerated. The most common adverse event was transient mild-moderate fever. Median OS time was significantly longer in the primed combination group compared with both LE (414 vs 223 days; hazard ratio [HR], 0.48; P = 0.043) and unprimed combination (414 vs 141.5 days; HR, 0.24; P = 0.0056). Patients in the combination phase of the primed combination group had a median PFS time of 90 days compared with 60 in the LE group (HR, 0.36; P = 0.032), and 63 in the unprimed combination group (P = 0.72). Radiographic responders to VB-111 exhibited characteristic, expansive areas of necrosis in the areas of initial enhancing disease.

CONCLUSIONS

Patients with rGBM who were primed with VB-111 monotherapy that continued after progression with the addition of bevacizumab showed significant survival and PFS advantage, as well as specific imaging characteristics related to VB-111 mechanism of action. These results warrant further assessment in a randomized controlled study.

Ofranergene obadenovec (VB-111) in platinum-resistant ovarian cancer; favorable response rates in a phase I/II study are associated with an immunotherapeutic effect

OBJECTIVE

Report final results of a phase I/II study of VB-111, a targeted anti-cancer gene therapy with a dual mechanism: anti angiogenic/vascular disruption and induction of an anti-tumor directed immune response, in combination with paclitaxel in patients with platinum-resistant ovarian cancer.

METHODS

Study NCT01711970 was a prospective, open label, dose escalation study assessing combination treatment of VB-111 and weekly paclitaxel. In the Phase I part of the study, patients were treated with escalating doses of intravenous VB-111 and paclitaxel. In Phase 2, patients were treated with therapeutic doses of VB-111 and paclitaxel 80 mg/m². Assessments included safety, overall survival (OS), progression free survival (PFS), and tumor response (CA-125 and RECIST).

RESULTS

21 patients with recurrent platinum-resistant ovarian cancer were enrolled. 17/21 received the therapeutic dose. Patients had a median of 3 prior lines of therapy. Half of the subjects were platinum refractory, and half were previously treated with antiangiogenics. No DLTs were observed. VB-111 was well tolerated and associated with mild flu-like symptoms. In the therapeutic dose cohort, a 58% CA-125 GCIG response rate was seen in evaluable patients. The median OS was 16.6 months in patients treated with therapeutic dose compared to 5.8 months in sub-therapeutic dose (p = 0.028). Tumor specimens taken after treatment demonstrated tumor infiltrated with cytotoxic CD8 T-cells in regions of apoptotic cancer cells.

CONCLUSIONS

Treatment with VB-111 in combination with paclitaxel was safe and well tolerated. Favorable tumor responses and overall survival outcomes were associated with induction of an immunotherapeutic effect.

NIMG-47. VOLUMETRIC ANALYSIS OF PHASE 2 AND 3 TRIALS IN RECURRENT GLIOBLASTOMA TREATED WITH VB-111 WITH OR WITHOUT BEVACIZUMAB OR BEVACIZUMAB MONOTHERAPY

VB-111 is a non-replicating adenovirus carrying a pro-apoptotic transgene for TNFR1/Fas under the control of a modified murine promoter to pre-proendothelin 1. The transgene is expressed only in angiogenic endothelial cells, and therefore VB-111 results in targeted apoptosis of neovascular vessels. The current study characterizes the quantitative radiographic results and impact on OS in phase 2 and 3 trials of recurrent glioblastoma (GBM) patients treated with VB-111 with or without bevacizumab (BV) or BV monotherapy. MRI data from a phase 2 (NCT01260506) and randomized, double arm, controlled phase 3 (GLOBE; NCT02511405) trial of VB-111 in recurrent GBM were used in current study: Arm A) VB-111 monotherapy until progression followed by combination VB-111 and bevacizumab (BV) (“Primed Combination”; Phase 2; N=24); Arm B) VB-111 in combination with BV (“Unprimed Combination”; Phase 3; N=124); Arm C) BV monotherapy (“Control”; Phase 3; N=120). Contrast enhanced T1-weighted digital subtraction was used to quantify tumor volume at all time points. Baseline tumor volume was prognostic for OS in all treatment groups when controlling for therapy and age (Cox, P< 0.001, HR=1.02). In patients with smaller tumors (< 25mL), the “primed combination” cohort (Arm A) from the phase 2 trial had a significant OS advantage compared to both upfront combination of VB-111 and BV (Arm B; P=0.0094, HR=0.53; median OS = 7 vs. 15mo) as well as BV alone (Arm C; P=0.025, HR=0.58; median OS=8.5 vs. 15mo). Patients with a radiographic response (>65% reduction) had a significant survival difference from non-responders when controlling for age, baseline tumor volume, and treatment arm (P=0.0014, HR=0.58). Responders to VB-111 monotherapy or combination therapy after priming with VB-111 exhibited characteristic, expansive areas of necrosis in areas of initial disease.

ATIM-09. CLINICAL TRIAL IN PROGRESS: A STUDY OF NEOADJUVANT AND ADJUVANT VB-111 FOR TREATMENT OF RECURRENT GBM

BACKGOUND

Ofranergene obadenovec (VB-111) is a targeted anti-cancer viral based gene therapy with a dual mechanism: a broad antiangiogenic effect and induction of a tumor directed immune response. Previous study demonstrated a survival benefit for patients with recurrent glioblastoma (rGBM) treated with VB-111 monotherapy that was continued upon progression with combination treatment of VB-111 and bevacizumab. Glioblastoma is an immunologically “cold” microenvironment which fosters immunosuppression and antagonizes anti-tumor immune responses. The role of T-cell infiltration in combating cancer has been increasingly recognized and associated with improved participant outcomes. Based on these observations, this study will assess the hypothesis that neoadjuvant use of VB-111 will lead to a statistically significant increase in tumor infiltrating T lymphocyte (TIL) density within the tumor and enhanced systemic tumor-specific T cell responses.

METHODS

This is a multicenter, randomized, blinded, placebo-controlled, phase 2 surgical trial to evaluate early immunologic pharmacodynamic parameters for the viral cancer therapy VB-111 in rGBM. 45 participants with rGBM indicated for resection will randomized to one of three treatment arms: Neoadjuvant Arm: intravenous VB-111 prior to resection, and VB-111 every 6 weeks after resection. Adjuvant Arm: placebo prior to resection, and VB-111 every 6 weeks afterwards. The control arm will receive placebo prior to resection followed by standard of care. Upon evidence of contrast-enhancing progression, bevacizumab may be initiated as needed for supportive care and VB-111 will continue until progression is supported at two consecutive time points. Tumor samples will be obtained and archived at the time of surgery, and blood samples will be obtained as pharmacodynamic markers throughout the study to allow DNA sequencing of T cells. The primary endpoint is influence of neoadjuvant VB-111 on TIL density. Other endpoints include safety and tolerability, peripheral T cell response, tumor/microenvironment transcriptomic alteration, and PFS/OS. Study will open for enrolment in 2019.

NIMG-54. DIFFUSION MRI PHENOTYPES PREDICT OVERALL SURVIVAL BENEFIT FROM BEVACIZUMAB IN RECURRENT GLIOBLASTOMA WITH A LARGE TUMOR BURDEN: EVIDENCE FROM CLINICAL PRACTICE AND A MULTICENTER PHASE 3 TRIAL

We have previously shown that diffusion MR characteristics are a predictive imaging biomarker for survival benefit in recurrent glioblastoma treated with anti-VEGF therapy; however, contemporary clinical use of bevacizumab is often limited to patients with very large tumors and/or after multiple recurrences. We hypothesize that diffusion MR characteristics can be used to predict long-term survival benefit in these patients, which may be beneficial for clinical decision-making. The current study identified 83 recurrent glioblastoma patients from our institution who were treated with bevacizumab over the past 5 years with high quality anatomic and diffusion MRI data. Of these 83 patients, 35 had large contrast enhancing tumors (>20cc or >3.4cm diameter, group average). Additionally, we identified 37 recurrent glioblastoma patients from the bevacizumab treated control arm of a recent multicenter phase III trial (NCT02511405) with high quality data and large enhancing tumors for validation. Pre-treatment tumor volume was quantified using T1 subtraction maps and apparent diffusion coefficient (ADC) histogram analysis was used to phenotype patients as having high (> 1.24 um2/ms) or low (< 1.24 um2/ms) ADCL, the mean value of the lower peak using a double Gaussian mixed model. Median overall survival in patients with large volume recurrent glioblastoma was ~5.7 months. High ADCL was associated with significantly longer overall survival (OS) compared with low ADCL in both single center (P=0.0271, HR=0.486, mOS=5.5 vs. 2.8mo) and multicenter phase III data (P=0.0457, HR=0.507, mOS=7.9 vs. 5.7mo). Accounting for absolute tumor volume and age, both cohorts showed that ADCL was an independent prognostic factor for OS (Cox, P< 0.01). In summary, pre-treatment diffusion MR imaging is an independent predictive biomarker for OS in recurrent glioblastoma with a large tumor burden.

Ofranergene obadenovec (VB-111) in platinum resistant ovarian cancer: with an immunotherapeutic effect

5542

Background: VB-111 is a targeted anti-cancer gene therapy with a dual mechanism: anti angiogenic/vascular disruption and induction of an anti-tumor directed immune response. We report final results of a phase I/II study of VB-111 in combination with paclitaxel in patients with platinum-resistant ovarian cancer. Methods: Study NCT01711970 was a prospective, open label, dose escalating study assessing combination treatment of VB-111 Q8W and weekly Paclitaxel. In the phase I part of the study patients were treated with escalating doses of intravenous VB-111 and Paclitaxel. In phase 2 patients were treated with therapeutic doses of VB-111 1x1013 Viral Particles and paclitaxel 80mg/m2. Assessments included safety, overall survival (OS), PFS, tumor response (CA-125 and RECIST) and histopathology. Results: 21 patients with recurrent platinum-resistant ovarian cancer were enrolled and treated in 2 US sites. Patients received a mean of 2.3 ±1.8 repeat doses of VB-111. 17/21 received the therapeutic dose. Median age was 65 (41-79) with a median of 3 (1-4) prior lines of therapy. Half of the subjects were Platinum refractory, and half were previously treated with antiangiogenics. No DLTs were observed. VB-111 was well tolerated and was associated with generally mild flu-like symptoms. In the therapeutic dose cohort, a 58% CA-125 GCIG response rate was seen in evaluable patients including durable responses, and responses in patients with platinum refractory disease and post anti-angiogenic failure . The median OS was 498 days in patients treated with Therapeutic Dose compared to 173 days in Sub-therapueutic dose (p = 0.028). Tumor Specimens taken after treatment demonstrated tumor infiltrated with cytotoxic CD8 T-cells and regions of apoptotic cancer cells. Conclusions: Treatment with VB-111 in combination with weekly Paclitaxel was safe and well tolerated. Favorable tumor responses and overall survival outcomes were associated with induction of an immunotherapeutic effect manifested as tumor infiltration with CD-8 T cells. Encouraging results are the basis for further exploration in the ongoing, placebo controlled, pivotal OVAL study. Clinical trial information: NCT01711970.

Quantitative radiographic analysis of phase II and III trials in recurrent glioblastoma treated with VB-111 with or without bevacizumab or bevacizumab monotherapy

2018

Background: VB-111 is a non-replicating adenovirus carrying a pro-apoptotic transgene for TNFR1/Fas under the control of a modified murine promoter to pre-proendothelin 1. The transgene is expressed only in angiogenic endothelial cells, and therefore VB-111 results in targeted apoptosis of neovascular vessels. The current study characterizes the quantitative radiographic results and impact on OS in phase 2 and 3 trials of recurrent glioblastoma (GBM) patients treated with VB-111 with or without bevacizumab (BV) or BV monotherapy. Methods: MRI data from a phase 2 (NCT01260506) and randomized, double arm, controlled phase 3 (GLOBE; NCT02511405) trial of VB-111 in recurrent GBM were used in current study: Arm A) VB-111 monotherapy until progression followed by combination VB-111 and bevacizumab (BV) (“Primed Combination”; Phase 2; N = 24); Arm B) VB-111 in combination with BV (“Unprimed Combination”; Phase 3; N = 124) and Arm C) BV monotherapy (“Control”; Phase 3; N = 120). Contrast enhanced T1-weighted digital subtraction was used to quantify tumor volume at all time points. Results: Baseline tumor volume was not significantly different between patient cohorts (Kruskal-Wallis; P = 0.1482; median~20mL). Continuous measures of baseline tumor volume were prognostic for OS in all treatment groups when controlling for therapy and age (Cox, P < 0.001, HR = 1.02). In patients with small tumors ( < 25mL), the “primed combination” cohort (Arm A) from the phase 2 trial had a significant OS advantage compared to both upfront combination of VB-111 and BV (Arm B; P = 0.0094, HR = 0.5328; median OS = 7mo vs. 15mo) as well as BV alone (Arm C; P = 0.0248, HR = 0.5776; median OS = 8.5mo vs. 15mo). Patients with a radiographic response ( > 65% reduction) had a significant survival difference from non-responders when controlling for age, baseline tumor volume, and treatment arm ( P = 0.0014, HR = 0.5822). Notably, in responders to VB-111 monotherapy or combination therapy after priming with VB-111 exhibited characteristic, expansive areas of necrosis in areas of initial disease. Conclusions: Small recurrent tumors have a significant OS advantage when “priming” with VB-111 monotherapy prior to combination VB-111 and BV at recurrence. Patients responding to VB-111 exhibit specific imaging characteristics related to the drug mechanism of action. Clinical trial information: NCT02511405; NCT01260506.