The ability of tumors to evade detection by the immune system via inducing immunosuppression prompted the therapeutic development of immune checkpoint inhibitors. In our recent review, we discussed findings from preclinical and clinical investigations of these agents utilized in combination with radiation inducing abscopal (systemic) antitumor effects.

Background

Older adults aged 65 years and above remain underrepresented in cancer clinical trials. We hypothesized that older participation in early phase trials with VEGF/VEGFR (VEGF/R) inhibitors was lower than cancer prevalence in this group and lower than other age groups (middle age, adolescent/young adults [AYA]).

Results

Of 1489 patients, 278 were older adults (18%, median age 68.9y), 220 AYA (15%, median age 32.6 y), 991 middle age (67%, median age 53.8 y). Common malignancies included gastrointestinal (n = 438, 29%), gynecologic (n = 234, 16%), and thoracic/head/neck (n = 216, 15%). Median time to treatment failure did not vary significantly between the 3 age-based cohorts (3m in older adults, 3.5 m middle age, 3.3 m AYA). OR of achieving clinical benefit in older adults vs middle age (OR 1.10, p 0.19 [two-tailed], p 0.09 [one-tailed]) and AYA vs middle age (OR 0.85, p 0.31 [proportions z-test, two tailed], p 0.15 [one-tailed]) showed no significant differences.

Conclusions

Older adults accounted for <20% of participants on phase I clinical trials with VEGF/R inhibitors but those who participated were just as likely to achieve a clinical benefit as AYA and middle age patients. These findings merit further exploration into patient selection for early phase trials.

Methods

We identified and separated patients treated on VEGF/R-inhibitor-based phase I trials from 12/1/2004-07/31/2013 into 3 age-based cohorts, AYA (15-39y), middle age (40-64 y), older adults (65 y+). We analyzed clinical/treatment characteristics and response outcomes, calculating the odds ratios (OR) of clinical benefit (defined as SD ≥ 6months, PR, CR) for older adults and AYAs versus middle age participants.

Purpose

MET alterations including amplifications and nucleotide variations have been associated with resistance to therapy and aggressive clinical behavior.

Experimental design

The medical records of patients presenting to the University of Texas MD Anderson Cancer Center Phase I Clinic with relapsed or metastatic ovarian cancers and known MET nucleotide variation or amplification status were reviewed retrospectively (n=178). Categorical and continuous clinical and molecular characteristics were compared using Fisher's exact and Wilcoxon rank-sum tests, respectively. Univariate and multivariate survival were assessed via Kaplan-Meier and Cox regression analysis, respectively.

Results

MET amplification occurred in 4 (3.5%) of 113 patients, whereas nonsynonomous nucleotide variations were present in 9 (7.4%) of 122 patients. No patients exhibited concomitant amplification and variation. MET variations were observed only in white women with high-grade ovarian tumors, whereas amplifications were observed in both black and white women with high-grade serous ovarian primary tumors. No patients (n=4) exhibiting a MET alteration achieved an objective response when treated on a c-Met inhibitor phase I trial. In addition, ovarian cancer patients treated with a c-Met inhibitor with multikinase activity trended towards a longer time-to-failure compared with those treated with a c-Met-specific inhibitor (median: 1.5 vs. 4.5 months, p=0.07).

Conclusions

MET alterations occur in a minority of patients with ovarian cancer. c-Met inhibitors with multikinase activity may exhibit less activity in ovarian cancer than c-Met specific drugs. These findings warrant further investigation.

With the recent success of checkpoint inhibitors and other immunomodulating agents, there has been renewed interest in the combination of such agents with radiation. The biologic premise behind such a strategy is that the tumor-antigen release achieved by localized radiation will promote specific tumor targeting by the adaptive immune system, which can be augmented further by systemic immune-stimulating agents. In this manner, clinicians hope to induce a phenomenon known as the abscopal effect, whereby localized radiation results in immune-mediated tumor regression in disease sites well outside of the radiation field. Herein, we present a comprehensive overview of the early clinical and preclinical evidence behind this approach.

Background

The purpose of this study was to determine the prevalence of MET amplification and mutation among GU malignancies and its association with clinical factors and responses to c-MET inhibitors.

Patients and methods

Patients with GU malignancies referred to our Phase I Clinical Trials Program were evaluated for MET mutation and amplification and outcomes using protocols with c-MET inhibitors.

Results

MET amplification was found in 7 of 97 (7.2%) patients (4/27 renal [all clear cell], 1/18 urothelial, and 2/12 adrenocortical carcinoma), with MET mutation/variant in 3 of 54 (5.6%) (2/20 renal cell carcinoma [RCC] [1 clear cell and 1 papillary] and 1/16 prostate cancer). No demographic characteristics were associated with specific MET abnormalities, but patients who tested positive for mutation or amplification had more metastatic sites (median, 4 vs. 3 for wild type MET). Median overall survival after phase I consultation was 6.1 and 11.5 months for patients with and without a MET alteration, respectively (hazard ratio, 2.8; 95% confidence interval, 1.1 to 6.9; P = .034). Twenty-nine (25%) patients were treated according to a c-MET inhibitor protocol. Six (21%) had a partial response (prostate and RCC) and 10 (34%) had stable disease as best response. Median time to tumor progression was 2.3 months (range, 0.4-19.7) for all treated patients with no responses in patients with a MET abnormality or single-agent c-MET inhibitor treatment.

Conclusion

MET genetic abnormalities occur in diverse GU malignancies and are associated with a worse prognosis in a phase I setting. Efficacy of c-MET inhibitors was more pronounced in patients without MET abnormalities and when combined with other targets/drugs.

Background

We performed a phase I modified 3 + 3 dose escalation study to evaluate the safety and activity of bevacizumab plus gemcitabine and nab-paclitaxel in patients with advanced solid tumours.

Methods

Patients were given fixed dose gemcitabine plus increasing doses of nab-paclitaxel and bevacizumab. Toxicity, response, and association with VEGF polymorphism was analysed.

Results

The study enrolled 110 patients who had undergone a median of 3 prior lines of therapy. The median age was 60 years (range, 17-85 years), and 55 patients (50%) had gemcitabine-refractory disease. We observed 3 dose-limiting toxicities during dose escalation and 3 DLTs in expansion cohorts. Dose escalation to 150 mg/m² nab-paclitaxel and 15 mg/kg bevacizumab with 1000 mg/m² of gemcitabine was well tolerated with no MTD. One patient with gemcitabine-refractory peritoneal papillary carcinoma had a complete response, 13 patients (13%) had partial responses, and 54 patients (52%) had stable disease ≥12 weeks. Exploratory VEGF single nucleotide polymorphism (SNP) analysis was performed on 13 patients.

Conclusions

The combination of gemcitabine, nab-paclitaxel, and bevacizumab is safe, well-tolerated, and has activity in advanced malignancies, including gemcitabine-refractory tumours. Based on this study, the recommended phase 2 dose is gemcitabine 1000 mg/m², nab-paclitaxel 125 mg/m², and bevacizumab 15 mg/kg. VEGF polymorphism data should be evaluated in future bevacizumab-based trials.

We sought to investigate the demographics and tumor-associated features in patients with gastroesophageal (GE) malignancies referred to our Phase I Program who had formalin-fixed, paraffin-embedded tissue from archival or new biopsies tested for MET mutation and/or amplification. MET amplification was found in 5 of 76 (6.6%) patients (3/34 [8.8%] esophageal, 2/26 [7.7%] gastric and none in 22 gastroesophageal junction cancers). The only MET mutation detected in 3 of 41 (7.3%) patients was N375S. No demographic and histologic characteristics were associated with specific MET abnormalities. Median overall survival was 3 and 5 months for patients with and without a MET alteration, respectively (hazard ratio [HR] = 2.1; 95% CI, 0.8 to 5.5; P=.14). Sixteen of 81 (20%) patients were enrolled in a c-MET inhibitor trial. Best responses were stable disease in 3 patients (19%), including a patient with esophageal adenocarcinoma that remained on the trial for 9.9 months (wild-type for MET abnormality). All tumors with MET abnormality (n=3) progressed on a c-MET inhibitor in fewer than 2 months. In conclusion, MET abnormalities can be found in a small group of patients with GE adenocarcinoma and further studies are necessary to better characterize the prognostic and predictive impact of MET alterations.

Human pluripotent stem cells, including human embryonic stem cells (hESCs) and human induced PSCs (hiPSCs), have great potential as an unlimited donor source for cell-based therapeutics. The risk of teratoma formation from residual undifferentiated cells, however, remains a critical barrier to the clinical application of these cells. Herein, we describe external beam radiation therapy (EBRT) as an attractive option for the treatment of this iatrogenic growth. We present evidence that EBRT is effective in arresting growth of hESC-derived teratomas in vivo at day 28 post-implantation by using a microCT irradiator capable of targeted treatment in small animals. Within several days of irradiation, teratomas derived from injection of undifferentiated hESCs and hiPSCs demonstrated complete growth arrest lasting several months. In addition, EBRT reduced reseeding potential of teratoma cells during serial transplantation experiments, requiring irradiated teratomas to be seeded at 1 × 10³ higher doses to form new teratomas. We demonstrate that irradiation induces teratoma cell apoptosis, senescence, and growth arrest, similar to established radiobiology mechanisms. Taken together, these results provide proof of concept for the use of EBRT in the treatment of existing teratomas and highlight a strategy to increase the safety of stem cell-based therapies. Stem Cells 2017;35:1994-2000.

PURPOSE: Data comparing radical prostatectomy and external beam radiation therapy with low dose rate brachytherapy boost are lacking. To better guide shared decision making regarding treatment, we compared patient reported outcomes through 5 years following radical prostatectomy or external beam radiation therapy with low dose rate brachytherapy boost for localized prostate cancer. MATERIALS AND METHODS: From 2011-2012, men aged <80 years with localized prostate adenocarcinoma were enrolled and followed longitudinally. Patient reported outcomes included the Expanded Prostate Index Composite. Regression models adjusted for baseline scores and covariates were constructed. RESULTS: The study population included 112 men treated with external beam radiation therapy with low dose rate brachytherapy boost and 1,553 treated with radical prostatectomy. Compared to radical prostatectomy, external beam radiation therapy with low dose rate brachytherapy boost was associated with clinically meaningful worse urinary irritative/obstructive (adjusted mean score difference [95% confidence interval]: 5.0 [-8.7, -1.3]; P = .008 at 5 years) and better urinary incontinence function (13.3 [7.7, 18.9]; P < .001 at 5 years) through 5 years. Urinary function bother was similar between groups (P > .4 at all timepoints). Treatment with external beam radiation therapy with low dose rate brachytherapy boost was associated with worse bowel function (-4.0 [-6.9, -1.1]; P = .006 at 5 years) through 5 years compared to radical prostatectomy. Treatment with external beam radiation therapy with low dose rate brachytherapy boost was associated with better sexual function at 1 year (12.0 [6.5, 17.5]; P < .001 at 1 year) compared to radical prostatectomy, but there was insufficient evidence to reject the supposition that no difference was seen at 3 or 5 years. CONCLUSIONS: Compared to radical prostatectomy, external beam radiation therapy with low dose rate brachytherapy boost was associated with clinically meaningful worse urinary irritative/obstructive and bowel functions but better urinary incontinence function through 5 years after treatment. These patient-reported functional outcomes may clarify treatment expectations and help inform treatment choices for localized prostate cancer.