Despite extraordinary advances that have been achieved in the last few decades, cancer continues to represent a leading cause of mortality worldwide. Lethal cancer types ultimately become refractory ...to standard of care approaches; thus, novel effective treatment options are desperately needed. Tumor Treating Fields (TTFields) are an innovative non-invasive regional anti-mitotic treatment modality with minimal systemic toxicity. TTFields are low intensity (1-3 V/cm), intermediate frequency (100-300 kHz) alternating electric fields delivered to cancer cells. In patients, TTFields are applied using FDA-approved transducer arrays, orthogonally positioned on the area surrounding the tumor region, with side effects mostly limited to the skin. The precise molecular mechanism of the anti-tumor effects of TTFields is not well-understood, but preclinical research on TTFields suggests it may act during two phases of mitosis: at metaphase, by disrupting the formation of the mitotic spindle, and at cytokinesis, by dielectrophoretic dislocation of intracellular organelles leading to cell death. This review describes the mechanism of action of TTFields and provides an overview of the most important
studies that investigate the disruptive effects of TTFields in different cancer cells, focusing mainly on anti-mitotic roles. Lastly, we summarize completed and ongoing TTFields clinical trials on a variety of solid tumors.
JCO
The initial STOMP and ORIOLE trial reports suggested that metastasis-directed therapy (MDT) in oligometastatic castration-sensitive prostate cancer (omCSPC) was associated with improved treatment ...outcomes. Here, we present long-term outcomes of MDT in omCSPC by pooling STOMP and ORIOLE and assess the ability of a high-risk mutational signature to risk stratify outcomes after MDT. The primary end point was progression-free survival (PFS) calculated using the Kaplan-Meier method. High-risk mutations were defined as pathogenic somatic mutations within
,
/
,
, or
. The median follow-up for the whole group was 52.5 months. Median PFS was prolonged with MDT compared with observation (pooled hazard ratio HR, 0.44; 95% CI, 0.29 to 0.66;
value < .001), with the largest benefit of MDT in patients with a high-risk mutation (HR high-risk, 0.05; HR no high-risk, 0.42;
value for interaction: .12). Within the MDT cohort, the PFS was 13.4 months in those without a high-risk mutation, compared with 7.5 months in those with a high-risk mutation (HR, 0.53; 95% CI, 0.25 to 1.11;
= .09). Long-term outcomes from the only two randomized trials in omCSPC suggest a sustained clinical benefit to MDT over observation. A high-risk mutational signature may help risk stratify treatment outcomes after MDT.
Lung cancer is the most common malignancy worldwide and is a focus for developing targeted therapies due to its refractory nature to current treatment. We identified a RNA helicase, DDX3, which is ...overexpressed in many cancer types including lung cancer and is associated with lower survival in lung cancer patients. We designed a first‐in‐class small molecule inhibitor, RK‐33, which binds to DDX3 and abrogates its activity. Inhibition of DDX3 by RK‐33 caused G1 cell cycle arrest, induced apoptosis, and promoted radiation sensitization in DDX3‐overexpressing cells. Importantly, RK‐33 in combination with radiation induced tumor regression in multiple mouse models of lung cancer. Mechanistically, loss of DDX3 function either by shRNA or by RK‐33 impaired Wnt signaling through disruption of the DDX3–β‐catenin axis and inhibited non‐homologous end joining—the major DNA repair pathway in mammalian somatic cells. Overall, inhibition of DDX3 by RK‐33 promotes tumor regression, thus providing a compelling argument to develop DDX3 inhibitors for lung cancer therapy.
Synopsis
The RNA helicase DDX3 is a new independent marker of lung cancer and targeted chemotherapy option. The novel inhibitor RK‐33, combined with radiation therapy, induces tumor regression in lung cancer models, with no toxicity at the therapeutic dose.
The RNA helicase DDX3 is overexpressed in lung cancer and is associated with lower survival in lung cancer patients.
Knockdown of DDX3 in highly aggressive lung cancer cell lines (H1299 and A549) curbed their colony‐forming abilities.
A small molecule inhibitor of DDX3, RK‐33, designed to bind to the nucleotide‐binding site within the DDX3 protein was synthesized.
RK‐33 was able to induce cell cycle arrest causing apoptosis in aggressive lung cancer, but not in normal cells, and promoted sensitization to radiation in DDX3‐overexpressing cells. Mechanistically, RK‐33 inhibited non‐homologous end joining and impaired Wnt signaling by disrupting the DDX3–β‐catenin axis.
RK‐33 in combination with radiation, induced tumor regression in multiple mouse models of lung cancer, while showing no toxicity at the therapeutic dose.
The RNA helicase DDX3 is a new independent marker of lung cancer and targeted chemotherapy option. The novel inhibitor RK‐33, combined with radiation therapy, induces tumor regression in lung cancer models, with no toxicity at the therapeutic dose.
TNFerade biologic is a novel means of delivering tumor necrosis factor alpha to tumor cells by gene transfer. We herein report final results of the largest randomized phase III trial performed to ...date among patients with locally advanced pancreatic cancer (LAPC) and the first to test gene transfer against this malignancy.
In all, 304 patients were randomly assigned 2:1 to standard of care plus TNFerade (SOC + TNFerade) versus standard of care alone (SOC). SOC consisted of 50.4 Gy in 28 fractions with concurrent fluorouracil (200 mg/m(2) per day continuous infusion). TNFerade was injected intratumorally before the first fraction of radiotherapy each week at a dose of 4 × 10(11) particle units by using either a percutaneous transabdominal or an endoscopic ultrasound approach. Four weeks after chemoradiotherapy, patients began gemcitabine (1,000 mg/m(2) intravenously) with or without erlotinib (100 to 150 mg per day orally) until progression or toxicity.
The analysis included 187 patients randomly assigned to SOC + TNFerade and 90 to SOC by using a modified intention-to-treat approach. Median follow-up was 9.1 months (range, 0.1 to 50.5 months). Median survival was 10.0 months for patients in both the SOC + TNFerade and SOC arms (hazard ratio HR, 0.90; 95% CI, 0.66 to 1.22; P = .26). Median progression-free survival (PFS) was 6.8 months for SOC + TNFerade versus 7.0 months for SOC (HR, 0.96; 95% CI, 0.69 to 1.32; P = .51). Among patients treated on the SOC + TNFerade arm, multivariate analysis showed that TNFerade injection by an endoscopic ultrasound-guided transgastric/transduodenal approach rather than a percutaneous transabdominal approach was a risk factor for inferior PFS (HR, 2.08; 95% CI, 1.06 to 4.06; P = .032). The patients in the SOC + TNFerade arm experienced more grade 1 to 2 fever and chills than those in the SOC arm (P < .001) but both arms had similar rates of grade 3 to 4 toxicities (all P > .05).
SOC + TNFerade is safe but not effective for prolonging survival in patients with LAPC.
To generate a map of local recurrences after pancreaticoduodenectomy (PD) for patients with resectable pancreatic ductal adenocarcinoma (PDA) and to model an adjuvant radiation therapy planning ...treatment volume (PTV) that encompasses a majority of local recurrences.
Consecutive patients with resectable PDA undergoing PD and 1 or more computed tomography (CT) scans more than 60 days after PD at our institution were reviewed. Patients were divided into 3 groups: no adjuvant treatment (NA), chemotherapy alone (CTA), or chemoradiation (CRT). Cross-sectional scans were centrally reviewed, and local recurrences were plotted to scale with respect to the celiac axis (CA), superior mesenteric artery (SMA), and renal veins on 1 CT scan of a template post-PD patient. An adjuvant clinical treatment volume comprising 90% of local failures based on standard expansions of the CA and SMA was created and simulated on 3 post-PD CT scans to assess the feasibility of this planning approach.
Of the 202 patients in the study, 40 (20%), 34 (17%), and 128 (63%) received NA, CTA, and CRT adjuvant therapy, respectively. The rate of margin-positive resections was greater in CRT patients than in CTA patients (28% vs 9%, P=.023). Local recurrence occurred in 90 of the 202 patients overall (45%) and in 19 (48%), 22 (65%), and 49 (38%) in the NA, CTA, and CRT groups, respectively. Ninety percent of recurrences were within a 3.0-cm right-lateral, 2.0-cm left-lateral, 1.5-cm anterior, 1.0-cm posterior, 1.0-cm superior, and 2.0-cm inferior expansion of the combined CA and SMA contours. Three simulated radiation treatment plans using these expansions with adjustments to avoid nearby structures were created to demonstrate the use of this treatment volume.
Modified PTVs targeting high-risk areas may improve local control while minimizing toxicities, allowing dose escalation with intensity-modulated or stereotactic body radiation therapy.
We describe a randomized, non-blinded Phase II interventional study to assess the safety and efficacy of stereotactic ablative radiotherapy (SABR) for hormone-sensitive oligometastatic prostate ...adenocarcinoma, and to describe the biology of the oligometastatic state using immunologic, cellular, molecular, and functional imaging correlates. 54 men with oligometastatic prostate adenocarcinoma will be accrued. The primary clinical endpoint will be progression at 6 months from randomization with the hypothesis that SABR to all metastases will forestall progression by disrupting the metastatic process. Secondary clinical endpoints will include local control at 6 months post-SABR, toxicity and quality of life, and androgen deprivation therapy (ADT)-free survival (ADT-FS). Further fundamental analysis of the oligometastatic state with be achieved through correlation with investigational
F-DCFPyL PET/CT imaging and measurement of circulating tumor cells, circulating tumor DNA, and circulating T-cell receptor repertoires, facilitating an unprecedented opportunity to characterize, in isolation, the effects of SABR on the dynamics of and immunologic response to oligometastatic disease.
Patients will be randomized 2:1 to SABR or observation with minimization to balance assignment by primary intervention, prior hormonal therapy, and PSA doubling time. Progression after 6 months will be compared using Fisher's exact test. Hazard ratios and Kaplan-Meier estimates of progression free survival (PFS), ADT free survival (ADT-FS), time to locoregional progression (TTLP) and time to distant progression (TTDP) will be calculated based on an intention-to-treat. Local control will be assessed using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. Withdrawal from the study prior to 6 months will be counted as progression. Adverse events will be summarized by type and grade. Quality of life pre- and post- SABR will be measured by Brief Pain Inventory.
The ORIOLE trial is the first randomized, non-blinded Phase II interventional study in the North America evaluating the safety and efficacy of SABR in oligometastatic hormone-sensitive prostate cancer. Leading-edge laboratory and imaging correlates will provide unique insight into the effects of SABR on the oligometastatic state.
ClinicalTrials.gov Identifier: NCT02680587. URL of Registry: https://clinicaltrials.gov/show/NCT02680587 Date of Registration: 02/08/2016. Date of First Participant Enrollment: 05/23/2016.
Pathogenic mutations in genes mediating homologous recombination (HR) DNA repair are present in 20–30% of men with metastatic castrate-resistant prostate cancer (mCRPC). Radium-223 is a bone-seeking ...α-emitter that induces double-strand DNA breaks, thereby killing cancer cells in the bone microenvironment.
To evaluate the potential impact of germline or somatic HR-deficiency (HRD) mutations on radium-223 efficacy in mCRPC with bone metastasis.
This is a retrospective single-institution study. Medical records of 190 mCRPC patients for whom germline and/or somatic DNA sequencing data were available were reviewed. Of these patients, 28 had received standard-of-care radium-223 at Johns Hopkins between February 2013 and February 2018.
Alkaline phosphatase (ALP) responses and time-to-ALP-progression were the coprimary endpoints. Prostate-specific antigen (PSA) responses, overall survival (OS), and time to next systemic therapy were also evaluated.
Of the 28 patients included, 10 men (35.7%) had a germline/somatic HRD mutation (three in BRCA2, and one each in ATM, ATR, CHEK2, FANCG, FANCI, FANCL, and PALB2) and 18 (64.3%) did not. Men with HRD mutations (HRD+) had numerically lower ages (66 vs 73yr, p=0.25), more soft-tissue metastases (50% vs 38%, p=0.43), and higher baseline ALP levels (130 vs 108 U/l, p=0.84). Compared with HRD(–) men, HRD(+) patients showed greater ALP responses (80% vs 39%, p=0.04), longer time to ALP progression (median10.4 vs 5.8mo, hazard ratio HR 6.4, p=0.005), and a trend toward longer OS (median 36.9 vs 19.0mo, HR 3.3, p=0.11). PSA responses (0% vs 0%, p>0.99) and time to next systemic therapy (HR 1.5, p=0.39) were similar between the two groups. Results are limited by the retrospective nature of the analysis and the small sample size.
In this exploratory study, bone-metastatic CRPC patients with inactivating HRD mutations demonstrated significantly improved ALP responses and time to ALP progression. These results should motivate prospective validation of the “synthetic lethality” hypothesis between HRD mutations and radium-223 activity.
In this report, we retrospectively examined outcomes to metastatic prostate cancer in patients with and without DNA repair mutations who received radium-223, a therapy that kills cancer cells by causing direct DNA damage. Our study suggested that patients who have inherited or acquired DNA repair gene mutations derived greater benefit from radium-223 when compared with patients without these mutations. We concluded that radium-223 might have an important role in this setting; however, prospective studies are needed to confirm whether DNA repair mutations truly make radium-223 work better or not.
Our study showed that metastatic castrate-resistant prostate cancer patients with bone metastasis and inactivating homologous recombination deficiency (HRD) mutations have a significantly improved alkaline phosphatase (ALP) response and time to ALP progression. These results should motivate prospective validation of the “synthetic lethality” hypothesis between HRD mutations and greater radium-223 activity.
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