BETA prime: a first-in-man phase 1 study of AdAPT-001, an armed oncolytic adenovirus for solid tumors

AdAPT-001 is an oncolytic adenovirus (OAV) with a transforming growth factor beta (TGF-ß) trap, which neutralizes the immunosuppressive and profibrotic cytokine, TGF-ß. The aim or purpose of this phase 1 study was to assess the safety and tolerability and, secondarily, the efficacy of AdAPT-001 after single intratumoral injection (IT) (Part 1) and multidose IT injection (Part 2) in patients with superficially accessible, advanced refractory solid tumors. Part 1 enrolled 9 patients with a 3 + 3 single dose-escalation safety run-in involving 2.5 × 1011, 5.0 × 1011, 1.0 × 1012 viral particles (vps). No dose-limiting toxicities or treatment-related serious adverse events (SAEs) were seen. In Part 2, a dose-expansion phase, 19 patients received AdAPT-001 at 1.0 × 1012 vps until disease progression according to Response Evaluation Criteria in Solid Tumors or RECIST 1.1. The overall responses to treatment included confirmed partial responses (3), durable stable disease ≥ 6 months (5), and progressive disease (13). AdAPT-001 is well tolerated. Evidence of an anti-tumor effect was seen in both injected and uninjected lesions. The recommended Phase 2 dose was 1.0 × 1012 vp administered by intratumoral injection once every 2 weeks. Combination of AdAPT-001 with a checkpoint inhibition is enrolling.

Commentary on oncolytic viruses: past, present, and future

Whither oncolytic viruses? From the peak of their popularity in the early 2000s, when the ONYX-015 adenovirus had just entered the clinic, and then again in 2015 when the Food and Drug Administration-approved talimogene laherparepvec (also known as OncoVEXGM-CSF), which briefly revived interest, oncolytic viruses (OVs) have mostly fallen out of favor despite the many pharmaceutical companies with OVs in development.This commentary enumerates and addresses the core conceptions, perceptions, and misconceptions that characterize the current 'trough of disillusionment' in which the field of anticancer virotherapy finds itself and suggests reasons for optimism.

Data Management 101 for drug developers: A peek behind the curtain

In drug development a frequently used phrase is "data-driven". Just as high-test gas fuels a car, so drug development "runs on" high-quality data; hence, good data management practices, which involve case report form design, data entry, data capture, data validation, medical coding, database closure, and database locking, are critically important. This review covers the essentials of clinical data management (CDM) for the United States. It is intended to demystify CDM, which means nothing more esoteric than the collection, organization, maintenance, and analysis of data for clinical trials. The review is written with those who are new to drug development in mind and assumes only a passing familiarity with the terms and concepts that are introduced. However, its relevance may also extend to experienced professionals that feel the need to brush up on the basics. For added color and context, the review includes real-world examples with RRx-001, a new molecular entity in phase III and with fast-track status in head and neck cancer, and AdAPT-001, an oncolytic adenovirus armed with a transforming growth factor-beta (TGF-β) trap in a phase I/II clinical trial with which the authors, as employees of the biopharmaceutical company, EpicentRx, are closely involved. An alphabetized glossary of key terms and acronyms used throughout this review is also included for easy reference.

ROCKET: Phase II Randomized, Active-controlled, Multicenter Trial to Assess the Safety and Efficacy of RRx-001 + Irinotecan vs. Single-agent Regorafenib in Third/Fourth Line Colorectal Cancer

INTRODUCTION

RRx-001 is a novel cysteine-targeted alkylating agent that releases nitric oxide (NO). The primary biological activities of this hybrid molecule include macrophage repolarizing and vascular normalization. The purpose of this clinical trial (ROCKET) (NCT02096354) was to compare the safety and efficacy of the combination therapy RRx-001 + irinotecan vs. regorafenib in third/fourth line colorectal cancer that previously received treatment with irinotecan.

PATIENTS AND METHODS

A total of 34 patients were randomized (24 to RRx-001 + irinotecan (RxI) and 10 to single-agent regorafenib (RegI)) and were the basis for the intention-to-treat analysis (ITT, comprising all 34 patients). RRx-001 treatment was administered as an up-to-2-month "primer" followed by irinotecan for patients randomized to the RRx-001 arm (24). The efficacy and safety data are presented for the 34 patients in the (ITT) efficacy analysis. Therapy consisted of intravenous administration of RRx-001 at 4 mg once weekly for up to 2 months, at which point RRx-001 was discontinued, followed by intravenous infusion of irinotecan at 180 mg/m² on day 1 in a 21-day cycle vs. 160 mg oral regorafenib daily for 3/4 weeks followed at progression, if applicable, by irinotecan 180 mg/m² on day 1 in a 21-day cycle. There were 3 patients (3/24 = 12.5%) with prior single agent irinotecan on the RRx-001 randomized arm and 2 (2/10 = 20%) on the regorafenib randomized arm. Numerous patients had irinotecan combination therapies prior to randomized treatment. There were 15 patients on RRx-001 arm that received irinotecan post-RRx-001 in the randomized trial. There were 5 PRs on RRx-001 plus irinotecan leading to an overall response of 20.8% (5/24). There were 37.5% (9/24) of RRx-001 randomized patients with KRAS mutant type while 60% (6/10) regorafenib randomized patients were of KRAS type mutant. There were only 4 patients with available QOL and Edmonton Symptom Assessment System, an insufficient sample size to allow for any meaningful analysis.

RESULTS

Median patient follow-up was approximately 14.5 months (SD 4.5 months). Median overall survival was 8.6 months for RxI and 4.7 months for RegI. Median progression free survival was 6.1 months for RxI vs. 1.7 months for RegI (a statistically significant result, 2-sided log-rank test, P = .0030). The toxicity profile of RxI was substantially improved compared with RegI.

CONCLUSION

The results of this trial demonstrate improved efficacy of RxI compared with RegI in patients with metastatic colorectal cancer after previous treatment with irinotecan, and late-stage clinical development in this indication is planned on the strength of the observed "signal" accompanied by a sufficient safety profile.

Effect of RRx-001 on nephrotoxicity of cisplatin/etoposide in patients with solid tumors

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Background: RRx-001 is a small molecule anticancer agent that preclinically protects non-malignant tissues, but not tumors, against the cytotoxicities of chemotherapy and radiation. In a completed, multicenter Phase 2 trial, QUADRUPLE THREAT, patients with previously platinum-treated extrapulmonary small cell cancer (SCC), high-grade neuroendocrine carcinoma (HGNEC), non-small cell lung cancer (NSCLC), and genitourinary cancer (GUC) received 4 mg IV RRx-001 followed by etoposide plus cisplatin or carboplatin (EP). In addition to overall survival (OS), and progression-free survival (PFS), this study also evaluated the possible prevention of nephrotoxicity by RRx-001. Methods: 90 patients with SCC, HGNEC, NSCLC, and GUC that previously received ≥2 lines of therapy including a platinum doublet were treated with 4 mg RRx-001 IV once per week. At progression, RRx-001 was discontinued and 40 patients were re-challenged with IV etoposide 80-100 mg/m2 (Days 1, 2, and 3) and cisplatin 60-80 mg/m2 on Day 1 for 4-6 cycles. The co-primary endpoints were PFS and OS. For all patients, serum creatinine (Cr), blood urea nitrogen (BUN), and electrolytes were determined prior to, during and after each treatment cycle. Results: After 2 cycles of chemotherapy, no patients experienced BUN elevations above 20 mg/dL and creatinine beyond 1.5 mg/dL. After four cycles of chemotherapy, 36/40 (90%) patients experienced no elevations of BUN above 20 mg/dL and creatinine above 1.5 mg/dL and none of the patients experienced > Grade 2 elevations of creatinine. 1/40 (2.5%) patients experienced Grade 3 hypomagnesemia (0 Grade 4). 3/40 (7.5%) patients were dose reduced or withdrawn from the trial due to platinum-related adverse events. No patients experienced renal-related serious adverse events (SAEs). One patient experienced a renal failure SAE, which was not drug related. The cumulative OS and PFS median of all the tumor types were 8.6 and 6.4 months, respectively. Conclusions: 20%-35% of patients develop acute kidney injury after cisplatin administration. Based on published clinical literature, approximately 33% of patients experience kidney injury just days following initial treatment (p = 0.0034, two-sided chi-square test comparing our study nephrotoxicity of 10% (4/40) in the first four cycles against 33% historical rate), and 20% of patients taking high-dose cisplatin experience severe renal dysfunction. The nephrotoxic effect of cisplatin is cumulative. In this heavily platinum-treated population, none of the patients were ineligible to receive cisplatin as scheduled because their serum creatinine levels had failed to return to < or = 1.5 mg/dL. RRx-001 pretreatment did not affect the antitumor effects of EP as assessed by PFS and OS. This dose of RRx-001 warrants further evaluation as a nephroprotectant that reduces the cumulative renotoxic effects of cisplatin but not its antitumor efficacy. Clinical trial information: NCT02489903 .

Phase 2 randomized, active-controlled, multicenter trial to assess the safety and efficacy of RRx-001 + irinotecan vs. regorafenib + irinotecan in third/fourth-line colorectal cancer

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Background: RRx-001 is a novel cysteine-targeted alkylating agent that, upon binding, under severe hypoxia, which is primarily present in tumors, releases nitric oxide (NO) and other cytotoxic metabolites. The primary biological activities of this hybrid molecule include macrophage repolarization, CD47 downregulation, and vascular normalization. The purpose of this clinical trial (ROCKET) (NCT02096354) was to compare the safety and efficacy of the combination therapy RRx-001 + irinotecan vs. regorafenib + irinotecan in 3rd/4th line colorectal cancer that previously received treatment with irinotecan. Methods: A total of 34 patients were randomized (24 to RRx-001 + irinotecan (RxI) and 10 to regorafenib + irinotecan (RegI)) and were the basis for the intention-to-treat analysis (ITT, comprising all 34 patients). RRx-001 treatment was administered as an up-to-2-month induction therapy or “primer” followed by irinotecan for patients randomized to the RRx-001 arm (24). The efficacy and safety data are presented for the 34 patients in the ITT efficacy analysis. Therapy consisted of intravenous administration of RRx-001 at 4 mg once weekly for up to 2 months followed by intravenous infusion of irinotecan at 180 mg/m2 on day 1 in a 21-day cycle vs. 160 mg oral regorafenib daily for 3/4 weeks followed at progression, if applicable, by irinotecan 180 mg/m2 on day 1 in a 21-day cycle. Results: Median patient follow-up was approximately 14.5 months (SD 4.5 months). Median overall survival was 8.6 months for RxI and 4.7 months for RegI. Median progression free survival was 6.1 months for RxI vs. 1.7 months for RegI (a statistically significant result, two-sided log-rank test, p = 0.0030). Overall response rate was 20.8% for RxI vs. 0% for RegI. Moreover, the toxicity profile of RxI was substantially improved compared with RegI. Conclusions: The results of this trial demonstrate improved efficacy of RxI compared with RegI in patients with metastatic colorectal cancer after previous treatment with irinotecan, and late-stage clinical development in this indication is planned on the strength of the observed “signal” accompanied by a sufficient safety profile. Clinical trial information: NCT02096354 .

A Review of Persistent Post-COVID Syndrome (PPCS)

Persistent post-COVID syndrome, also referred to as long COVID, is a pathologic entity, which involves persistent physical, medical, and cognitive sequelae following COVID-19, including persistent immunosuppression as well as pulmonary, cardiac, and vascular fibrosis. Pathologic fibrosis of organs and vasculature leads to increased mortality and severely worsened quality of life. Inhibiting transforming growth factor beta (TGF-β), an immuno- and a fibrosis modulator, may attenuate these post-COVID sequelae. Current preclinical and clinical efforts are centered on the mechanisms and manifestations of COVID-19 and its presymptomatic and prodromal periods; by comparison, the postdrome, which occurs in the aftermath of COVID-19, which we refer to as persistent post-COVID-syndrome, has received little attention. Potential long-term effects from post-COVID syndrome will assume increasing importance as a surge of treated patients are discharged from the hospital, placing a burden on healthcare systems, patients' families, and society in general to care for these medically devastated COVID-19 survivors. This review explores underlying mechanisms and possible manifestations of persistent post-COVID syndrome, and presents a framework of strategies for the diagnosis and management of patients with suspected or confirmed persistent post-COVID syndrome.

Clinical Course of Two Patients with COVID-19 Respiratory Failure After Administration of the Anticancer Small Molecule, RRx-001

Two critically ill COVID-19 infected patients, who had exhausted all available treatment options, were treated with the small-molecule RRx-001 with subsequent improvement. RRx-001, a first-in-class small molecule with anti-inflammatory, vascular normalizing and macrophage-repolarizing properties, has been safely administered 300+ patients in clinical trials. This is the first report of RRx-001 treatment of COVID-19.

RRx-001 and the "Right stuff": Protection and treatment in outer space

From antibiotics to aspirin to antimalarials and to anticancer agents, about half of the world's best-selling drugs are derived from nature. However, accelerating climatic disruption, habitat destruction, pollution, and biodiversity loss all negatively impact the potential of natural sources to continue to serve as repositories of novel pharmaceuticals. On that basis, the final frontier for drug development is perhaps not the rainforests, coral reefs, and other natural habitats but rather the aerospace industry with its virtually unlimited and inexhaustible man-made 'library' of potentially bioactive compounds. The first aerospace-sourced therapeutic to reach the clinic is RRx-001, an inhibitor of the NOD-like receptor - Nucleotide-binding oligomerization domain with Leucine rich Repeat and Pyrin domain (NLRP3) inflammasome in a Phase 3 trial for the treatment of small cell lung cancer (SCLC) and in a soon-to-start Phase 3 trial for protection against chemoradiotherapy-induced severe oral mucositis in first line head and neck cancer. As manned missions to the Moon, Mars, and asteroids as well as space tourism beckon, it is perhaps fitting that a compound like RRx-001, which is derived from 1,3,3-Trinitroazetidine (TNAZ), an explosive propellant for rockets, is a potential "all purpose" option to mitigate the major biomedical effects of space radiation exposures including cancer development and other tissue degenerations both within mission and after mission. This article highlights the promise of RRx-001 to attenuate the acute and late effects of radiation exposure on astronauts including the development of cancer.

Subset analysis of safety and efficacy in asian patients treated with RRx-001 across three clinical trials

RRx-001, a CD47 antagonist via its inhibition of MYC and the γ-subtype of the peroxisome proliferator-activated receptor (PPAR) has been associated to date with minimal toxicity. The aim of this post-hoc analysis was to evaluate the toxicity and efficacy of RRx-001 in Asian patients since RRx-001, in the context of multiple Phase 3 studies, will be administered in China and Chinese territories as well as potentially throughout the rest of Asia. Patients received 4 mg of RRx-001 in three different antitumor clinical trials with chemotherapy and/or radiation and a retrospective subset efficacy and toxicity analysis was conducted for patients with Asian ancestry in comparison to patients with other ethnic backgrounds. The toxicity and efficacy data from these studies were similar between Asians and the rest of the treated patients. While the sample sizes are too small to draw definitive conclusions, at a dose of 4 mg, when RRx-001 is combined with chemotherapy, no apparent differences in terms of safety and efficacy are observed in cancer patients with Asian ancestry.

Phase 2 pilot trial of RRx-001 as an anti-mucositis agent in patients with head and neck cancer treated with chemoradiation (PREVLAR)

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Background: Severe oral mucositis (SOM) is a dose limiting toxicity during radiotherapy and cisplatin for head and neck cancers. The aim of this 4-arm randomized controlled pilot trial was to evaluate the efficacy of different schedules of a novel radioprotectant, RRx-001 versus standard-of-care (SOC), to reduce duration, time to onset and incidence of SOM in patients received cisplatin-based chemoradiotherapy (CRT) for oral cavity or oropharyngeal cancer (OCC). Methods: Patients with locally advanced OCC treated with definitive or postoperative CRT were randomized to receive RRx-001 by 15-minute intravenous infusion in one of three different schedules versus none. The days and severity of mucositis were prospectively evaluated. Oral mucositis was assessed weekly during and after CRT as well as 28 days after completion. The pre-specified efficacy endpoints were duration of grade 3-4 SOM, resolution of SOM, time to onset of SOM and incidence of SOM. Results: A total of 53 patients were enrolled between June 2018 and July 2019 across 11 institutions. Forty-five (out of 53) patients received study drug and were efficacy evaluable. RRx-001 were well tolerated with no associated serious adverse events. All RRx-001 arms numerically outperformed SOC on the pre-specified efficacy measures, and the greatest effect estimate was observed on Arm 1 (RRx-001 pretreatment only + CRT). The following endpoints favored treatment with RRx-001. Median SOM duration by treatment was 22 and 40 days for Arm 1 and SOC respectively. Time to onset of SOM was by 38 days (Arm 1) vs. 26 days (SOC). On Arm 1, 83% of patients had SOM resolution vs 60% on SOC). Gastrostomy requirement was reduced by 45%. No patients on Arm 1 developed grade 4 mucositis vs 30% developed grade 4 mucositis on the SOC arm. Furthermore, the incidence of oropharyngeal dysphagia, which can substantially impair nutrition, was reduced by treatment with RRx-001, occurring at 50% vs 70% for Arm 1 vs SOC respectively. Treatment with RRx-001 resulted in highly significant decrease in the duration of SOM through 60 Gy with a median SOM of 1 day vs 17 days for Arm 1 vs SOC respectively (Wilcoxon rank-sum test p < 0.001). Median cumulative cisplatin dose was significantly greater for RRx-001 Arm 1 than SOC (557.4 mg vs. 438 mg, Wilcoxon p = 0.025). Conclusions: Compared with SOC, SOM among RRx-001-treated patients given 3 different treatment schedules was less severe, of shorter duration, demonstrated delayed time to onset and resolved earlier. Overall, the incidence, duration and severity of SOM and dysphagia was reduced. The safety profile of RRx-001 was similar to SOC. These results will inform the design of a Phase 3 pivotal study of RRx-001 in the prevention of SOM in at-risk cancer patients. Clinical trial information: NCT03515538.

Toxicology and biodistribution of AdAPT-001, a replication-competent type 5 adenovirus with a trap for the immunosuppressive cytokine, TGF-beta

Transgene-enhanced oncolytic adenoviruses represent a promising novel therapeutic option for the treatment of cancer. A Phase 1 clinical trial featuring AdAPT-001 is ongoing (NCT04673942). AdAPT-001, a type 5 adenovirus, which carries a TGF-β trap transgene that neutralizes the immunosuppressive cytokine, TGF-β, has been shown in an immunocompetent mouse model to eradicate both locally injected and non-injected tumors. Single dose biodistribution of the TGF-β trap transgene was also evaluated in tumor bearing mice, providing an explanation for systemic activity. The biodistribution and toxicity of a single administration of mouse AdAPT-001 (mAdAPT-001) in 129S1 immunocompetent mice bearing ADS-12 tumors (mouse lung carcinoma) were assessed. mAdAPT-001 was injected intratumorally and intravenously in groups of 25 mice each at varying dose levels. Soluble TGF-β trap was detected in the serum using ELISA. A single AdAPT-001 injection resulted in non-negligible long-term TGF-β trap persistence in the serum over the 14-day study after intravenous and intratumoral administration. No TGF-β-related toxicity was observed. At clinically relevant doses, AdAPT-001 was safe and well tolerated. Systemic levels of the TGF-β trap transgene were observed from both local and intravenous dosing.

A Patient-Derived Orthotopic Xenograft Model of Gastroesophageal-Junction Adenocarcinoma Translated to the Clinic by Tumor-Targeting Fluorescent Antibodies to Carcinoembryonic-Antigen-Related Cell-Adhesion Molecules

BACKGROUND/AIM

During surgical resection of gastroesophageal-junction (GEJ) adenocarcinoma, the margin status is often difficult to visualize resulting in high recurrence rates. The aim of the present study was to develop a labelling technique that would allow improved visualization of GEJ tumor margins for surgeons to reduce recurrence rates in a patient-like model.

MATERIALS AND METHODS

A patient GEJ tumor was obtained from an endoscopic biopsy and implanted subcutaneously in a nude mouse. A patient-derived orthotopic xenograft (PDOX) model was established by implanting tumor fragments grown from a subcutaneous model to the cardia of the stomach of nude mice. CC1/3/5-SAB, an antibody to carcinoembryonic-antigen-related cell-adhesion molecules, was conjugated with infrared dye IRDye800 to create SAB-IR800. Forty-eight hours after i.v. injection of SAB-IR800, GEJ-PDOX mice were imaged.

RESULTS

Fluorescence imaging with SAB-IR800 brightly visualized the GEJ adenocarcinoma demonstrating specific targeting. In the PDOX model, injection of SAB-IR800 (50 μg) resulted in a tumor to background ratio of 1.78 at 48 hours and 1.86 at 72 hours.

CONCLUSION

PDOX models of GEJ tumors can be established from patients by endoscopic biopsy without undergoing surgical resection. GEJ PDOX models should be useful for developing novel diagnostics and therapeutics for this recalcitrant disease.

Discovery of RRx-001, a Myc and CD47 Downregulating Small Molecule with Tumor Targeted Cytotoxicity and Healthy Tissue Cytoprotective Properties in Clinical Development

After extensive screening of aerospace compounds in an effort to source a novel anticancer agent, RRx-001, a first-in-class dinitroazetidine small molecule, was selected for advancement into preclinical and clinical development. RRx-001 is a minimally toxic small molecule with a distinct chemical structure and mechanism of action. The paradox of RRx-001 is that it mediates both antitumor cytotoxicity and normal tissue protection. The question of exactly how RRx-001 does this, and by means of what mechanism(s), depending on the route of delivery, intravenous or intratumoral, are explored. RRx-001 is currently in phase 2 and 3 clinical trials for the treatment of multiple solid tumor malignancies and as a supportive care drug.

An explorary analysis of a COVID-truncated REPLATINUM phase 3 trial in SCLC

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Background: RRx-001 is a small molecule immunotherapeutic in Phase 3 for the treatment of SCLC that is associated with M2-M1 tumor associated macrophage (TAM) repolarization with CD47 downregulation, vascular normalization and reversal of chemoresistance. In a controlled, multicenter clinical trial called REPLATINUM that was prematurely halted due to COVID-19, data from 17 patients with third line or beyond SCLC was analyzed. Moving forward, REPLATINUM(restarted) has added SARS-CoV-2 exclusion criteria. Our aim was to explore the efficacy of RRx-001 in REPLATINUM and to assess the statistical assumptions of the REPLATINUM(restarted) trial in order to inform future clinical development in SCLC. Methods: Patients in REPLATINUM were randomized to receive 1 of 2 arms: 1) carboplatin AUC 5 IV on day 1 or cisplatin 60 mg/m2 IV on day 1 plus etoposide 100 mg/m2 IV on days 1 through 3 every 21 days for up to 4 cycles or 2) 4 mg of RRx-001 administered sequentially with 4 cycles of a platinum doublet (cisplatin or carboplatin plus etoposide as outlined above). Progression Free Survival (PFS) was the primary efficacy endpoint based on a blinded independent central review (BICR). Results: The trial was suspended prematurely after 17 patients had been enrolled due to widespread COVID-19 exposure with the plan to restart the trial. The decision to restart the trial has provided an opportunity to examine the data for preliminary evidence of treatment efficacy. At the time that the REPLATINUM trial was halted, there were 11 patients enrolled on the control arm and 6 on the investigational arm. The BICR assessed median PFS was approximately 7.1 months for RRx-001 + platinum doublet and 3.5 months for the platinum doublet alone based on the truncated database. The BICR assessed PFS hazard ratio was approximately 0.5. OS medians were approximately 8.2 and 6.3 months for RRx-001 + platinum doublet and platinum doublet alone, respectively. Additionally, patients on the RRx-001 + platinum doublet-treated experimental arm experienced less toxicity than patients on the platinum doublet-treated control arm. Conclusions: Despite the small sample size, preliminary results from REPLATINUM suggest a trend toward a favorable primary outcome and improved safety in RRx-001-treated patients and support the validity of the statistical assumptions that underlie the REPLATINUM(restarted) trial. Pivotal evidence will emerge from REPLATINUM(restarted), which is imminently recommencing. Clinical trial information: NCT03699956.

A Review of Newly Diagnosed Glioblastoma

Glioblastoma is an aggressive and inevitably recurrent primary intra-axial brain tumor with a dismal prognosis. The current mainstay of treatment involves maximally safe surgical resection followed by radiotherapy over a 6-week period with concomitant temozolomide chemotherapy followed by temozolomide maintenance. This review provides a summary of the epidemiological, clinical, histologic and genetic characteristics of newly diagnosed disease as well as the current standard of care and potential future therapeutic prospects.

A short discussion about the SARS-CoV-2 mRNA-1273 vaccine

The COVID-19 global pandemic has prompted accelerated vaccine development efforts. This perspective discusses the importance of SARS-CoV-2 vaccine candidates’ recruitment of cellular T-cell immunity and encourages industry to increasingly investigate and publish parameters related to cellular immunity in their research reports.

RRx-001, a downregulator of the CD47- SIRPα checkpoint pathway, does not cause anemia or thrombocytopenia

Introduction: The CD47 and SIRPα checkpoint pathway has garnered much interest within the anti-cancer research community, with multiple experimental checkpoint inhibitors targeting CD47 and SIRPα in development. The use of such checkpoint inhibitors may however be limited by hematologic toxicity.Areas covered: We report on RRx-001, the first known small molecule downregulator of CD47 and SIRPα, which has shown a lack of hematologic toxicity in clinical trials.Expert opinion: RRx-001 is the first reported small molecule downregulator of CD47 and SIRPα and lacks any notable hematologic or systemic toxicity as demonstrated in clinical trials to date. Small molecule RRx-001 could be used in combination with or in place of CD47 targeting antibodies for anti-cancer treatment.

In small cell lung cancer patients treated with RRx-001, a downregulator of CD47, decreased expression of PD-L1 on circulating tumor cells significantly correlates with clinical benefit

Background

Small cell lung cancer (SCLC) is the most aggressive lung tumor, characterized by a rapid doubling time and the development of widespread metastases, for which immune checkpoint inhibitors have been approved to overcome T cell anergy. In light of its dismal prognosis, and lack of curative options, new therapies for extensive-disease SCLC are desperately needed.

Methods

RRx-001 is a small molecule Myc inhibitor and down-regulates CD47 expression on tumor cells. We evaluated the programmed death-ligand 1 (PD-L1) status of circulating tumor cells (CTCs) pre and post RRx-001 treatment in a phase 2 clinical trial, called QUADRUPLE THREAT, where patients with previously treated SCLC received RRx-001 in combination with a platinum doublet. The trial was registered with ClinicalTrials.gov, number NCT02489903. Fourteen patients with SCLC were analyzed to investigate the association between clinical outcome and PD-L1 expression on CTCs pre and post RRx-001. The correlation between the binary clinical outcome (clinical benefit vs. progressive disease) and the change of PD-L1 expression on CTCs after RRx-001 was analyzed using a logistic regression adjusting for baseline PD-L1 expression.

Results

The logistic model McFadden goodness of fit score was 0.477. The logistic model analyzing the association between decreased PD-L1 expression on CTCs after RRx-001 and response to reintroduced platinum doublet had an approximate 92.8% accuracy in its prediction of clinical benefit. The estimated receiver operating characteristic (ROC) displayed a ROC area under the curve (AUC) of 0.93 (95% confidence interval, 0.78–0.99).

Conclusions

These results suggest that PD-L1 expression on CTCs decreased after RRx-001 was significantly correlated with response to reintroduced platinum-based doublet therapy. Monitoring PD-L1 expression on CTCs during RRx-001 treatment may serve as a biomarker to predict response to RRx-001-based cancer therapy.

Desperate Times, Desperate Measures: The Case for RRx-001 in the Treatment of COVID-19

This article summarizes the likely attenuation properties of RRx-001 in COVID-19 based on its mechanism of action and the putative pathogenesis of the disease, which appears to activate inflammatory, oxidative, and immune cascades with the potential to culminate in acute respiratory distress syndrome, cytokine storm and death. An ongoing pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19 appears to present with 3 major patterns of clinical symptomatology: (1) mild upper respiratory tract infection, (2) non–life-threatening pneumonia, and (3) severe pneumonia and acute respiratory distress syndrome that initially manifest as a mild prodrome lasting for 7–8 days before rapid clinical and radiological deterioration requiring ICU transfer.

RRx-001 is a targeted nitric oxide donor. This small molecule, which has been evaluated in multiple Phase 1–2 clinical trials for cancer as well as a Phase 3 clinical trial for the treatment of small cell lung cancer called REPLATINUM (NCT03699956), is minimally toxic and demonstrates clear evidence of antitumor activity. During the course of these clinical trials it was noted that the rate of chronic obstructive pulmonary disease exacerbation and pneumonia in actively smoking small cell lung cancer patients treated with RRx-001 is less than 1%. Due to extensive history of tobacco use, 40%–70% of patients with lung cancer have chronic obstructive pulmonary disease and the expected rate of pulmonary infection in this population is 50%–70%, which was not observed in RRx-001 clinical trials. Moreover, in preclinical studies of pulmonary hypertension, RRx-001 was found to be comparable with or more effective than the FDA approved agent, Bosentan. The potential pulmonary protective effects of RRx-001 in patients with recurrent lung infections coupled with preclinical models demonstrating RRx-001-mediated reversal of pulmonary hypertension suggests RRx-001 may have therapeutic activity in patients with acute respiratory symptoms due to COVID 19. Clinical trials have been initiated to confirm the hypothesis that RRx-001 may be repurposed to treat SARS-CoV-2 infection.

Phase II expansion cohort in colorectal cancer to evaluate the safety and tolerability of RRx-001 blood mix

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Background: In a 34 patient randomized Phase 2 trial in 3rd/4th line colorectal cancer called ROCKET (NCT02096354) of RRx-001 + irinotecan versus regorafenib + irinotecan, RRx-001 + irinotecan demonstrated improved overall survival (OS) (8.6 vs 4.7 months) and progression free survival 2 (PFS2) (7.5 vs. 1.7 months) compared to the regorafenib control arm. The main adverse event attributed to RRx-001 treatment, which involved once weekly peripheral or central infusion, was a painful infusion-related superficial phlebitis in 80% of patients. Following the randomized portion of the ROCKET trial, another 18 colorectal patients were enrolled in an expansion cohort to evaluate the safety and tolerability of an RRx-001 “blood mix”, the objective of which was mitigation of the phlebitic complications of direct RRx-001 infusion. Methods: Therapy consisted of intravenous administration of RRx-001 at 4 mg once weekly via blood mix until progression followed by intravenous infusion of irinotecan at 180 mg/m2 on day 1 in a 21-day cycle. Results: The median OS and PFS2 were 6.3 and 5.2 months, respectively, which was similar to that of RRx-001 administered by direct infusion in the randomized part of the trial. No patients experienced phlebitis. The adverse event profile was otherwise unchanged compared with direct IV infusion of RRx-001. Conclusions: The results of this expansion cohort demonstrate similar activity of RRx-001 given by blood mix followed by irinotecan to RRx-001 given by direct IV infusion followed by irinotecan.RRx-001 alleviated the pain that had been observed in the direct IV infusion and therefore allowed for a shorter infusion time without any apparent compromise in activity (based on OS/PFS2 comparability to earlier results). Finally, since phlebitis in theory may progress to deep venous thrombosis or suppurative thrombophlebitis in hypercoagulable and immunosuppressed cancer patients, blood mix RRx-001 is the preferred method of infusion. Clinical trial information: NCT02096354 .

Correlation of decreased expression of PD-L1 on circulating tumor cells and clinical benefit in SCLC Patients treated with RRx-001, a CD47 downregulator, in a phase II trial

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Background: In a Phase 2 trial called QUADRUPLE THREAT (QT) (NCT02489903), where 2nd line+ small cell lung cancer (SCLC) patients were treated with RRx-001 and a platinum doublet, the programmed death-ligand 1 (PD-L1) status of circulating tumor cells (CTCs) in 14 patient samples was evaluated. Methods: 26 consented patients received weekly RRx-001 4 mg followed by a reintroduced platinum doublet; epithelial cell adhesion molecule (EPCAM+) CTCs from 10 ml of blood on two consecutive timepoints cycle 1 day 1 and cycle 3 day 8 (cycle duration = 1 week) were detected by EpCAM-based immunomagnetic capture and flow cytometric analysis. CTCs were further characterized for protein expression of PD-L1. Tumor response was classified as partial or complete response based on the response evaluation criteria in solid tumors (RECISTv1.1) measured every 6 weeks. Results: The analyzed clinical data set comprised 14 RECIST-evaluable patients. 50% were females (7/14) and the median age (years) at baseline was 64.5 (Min = 48.5, Max = 84.2, SD = 10.3). The logistic model McFadden goodness of fit score (0 to 100) is 0.477, which is a strong correlation value. The logistic model analyzing the association of CTC PD-L1 expression at two timepoints and response had an approximate 92.8% accuracy in its prediction of clinical benefit (SD/PR/CR). Accuracy is defined in the standard way as 1- (False positive rate + False negative rate). The estimated ROC displayed in Figure 1 suggests a ROC AUC of 0.93 (95% CI: 0.78, 0.99), an excellent measure of performance. Conclusions: Reduction of PD-L1 expression was correlated with good clinical outcome after RRx-001 + platinum doublet treatment. PD-L1 expression reduction in favor of RRx-001 RECIST clinical benefit was clinically significant as compared to non-responders with progressive disease (PD). In the ongoing SCLC Phase 3 study called REPLATINUM (NCT03699956), analyses are planned to correlate response and survival with expression of CD47 and PD-L1 on CTCs. Clinical trial information: NCT02489903.

Phase I study (PAYLOAD) of RRx-001 + irinotecan in patients with advanced solid malignancies

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Background: RRx-001 is a downregulator of CD-47 and SIRP-alpha, which demonstrated a clinically meaningful improvement in OS and PFS vs. regorafenib when dosed sequentially with irinotecan in a 3rd/4th line colorectal cancer randomized trial called ROCKET (NCT02096354). Recently, RRx-001 has been shown to downregulate PD-L1 on circulating tumor cells. This phase 1 trial named PAYLOAD (NCT02801097) was performed to assess the safety and tolerability of the combination of RRx-001 and irinotecan and to determine a recommended phase II dose (RP2D). Methods: Eligible patients (pts) had adequate organ and bone marrow functions and an ECOG of 0-2 and evaluable refractory advanced solid tumors. RRx-001 was administered once per week for 3 weeks and thereafter once every two weeks. RRx-001 was administered as a 10-15 min IV infusion with irinotecan, which began on Week 4 and which was also given every other week, staggered with RRx-001 . Dose escalation followed a standard 3 + 3 design with co-escalation of RRx-001 and irinotecan as follows: 1: Irinotecan 120 mg/m2 + RRx-001, 0.5 mg 2: Irinotecan 120 mg/m2 + RRx-001, 2 mg 3: Irinotecan 120 mg/m2 + RRx-001, 4 mg 4: Irinotecan 150 mg/m2 + RRx-001, 4 mg Radiological imaging was performed every 8 weeks. Results: 12 pts; 1 gallbladder, 1 ampullary carcinoma, 1 cholangiocarcinoma, 5 colon, 1 GE junction, 2 pancreatic and 2 rectal cancers were enrolled from January 2018 to November 2018. 1 and 18 doses (median: 6 doses) of the combination of RRx-001 and irinotecan were received. The median number of prior treatments was 4 (range 1-5). There were 2 Grade 3 events, leukopenia and anemia, judged not related to RRx-001 but related to irinotecan, 1 Grade 4 event, leukopenia, judged not related to RRx-001 but related to irinotecan and 1 Grade 5 event, neutropenic enterocolitis, also judged not related to RRx-001 but related to irinotecan. No dose-limiting toxicities were identified. The median overall survival was ~ 6.5 months. Conclusions: Alternating weekly infusions of 150 mg/m2 of irinotecan and 4 mg of RRx-001 were well tolerated. No Grade 2 or above diarrhea was observed with irinotecan treatment, which suggests that RRx-001 may protect against gastrointestinal (GI) toxicities, since RRx-001 has also demonstrated anti- oral mucositis and anti-diarrheal properties in other studies.This dose level is the recommended phase 2 dose for future trials. Clinical trial information: NCT02801097 .

TGF-beta: a master immune regulator

Introduction: Transforming Growth Factor-Beta (TGF-β) is a master regulator of numerous cellular functions including cellular immunity. In cancer, TGF-β can function as a tumor promoter via several mechanisms including immunosuppression. Since the immune checkpoint pathways are co-opted in cancer to induce T cell tolerance, this review posits that TGF-β is a master checkpoint in cancer, whose negative regulatory influence overrides and controls that of other immune checkpoints.Areas Covered: This review examines therapeutic agents that target TGF-β and its signaling pathways for the treatment of cancer which may be classifiable as checkpoint inhibitors in the broadest sense. This concept is supported by the observations that 1) only a subset of patients benefit from current checkpoint inhibitor therapies, 2) the presence of TGF-β in the tumor microenvironment is associated with excluded or cold tumors, and resistance to checkpoint inhibitors, and 3) existing biomarkers such as PD-1, PD-L1, microsatellite instability and tumor mutational burden are inadequate to reliably and adequately identify immuno-responsive patients. By contrast, TGF-β overexpression is a widespread and profoundly negative molecular hallmark in multiple tumor types.Expert Opinion: TGF-β status may serve as a biomarker to predict responsiveness and as a therapeutic target to increase the activity of immunotherapies.

RRx-001, a first-in-class small molecule inhibitor of MYC and a downregulator of CD47, is an "erythrophagoimmunotherapeutic"

The main mechanism of action of RRx-001, a pharmaceutically unprecedented sui generis Phase 3 small molecule that is derived from the aerospace industry, is clarified. RRx-001 has demonstrated anticancer activity through antiangiogenic, immune, epigenetic, antioxidant, apoptotic and nitric oxide (NO) pathways, resulting in its pleiomorphic description as an antiangiogenic/vascular normalizer.

Extended treatment with MY-NEOVAX, personalized neoantigen-enhanced oncolytic viruses, for two end-stage cancer patients

Neoantigen vaccines involving multi-peptides and poly-epitope-encoding RNA or DNA have undergone early phase clinical testing with modest reported antitumor effects [ 1]. The less-than-expected activity of these neoantigenic vaccines may correspond with the development of immune escape mechanisms. One permutation on neoantigen vaccines, which may counter or prevent these adaptive immune escape mechanisms, are 'personalized' oncolytic viruses that encode one or more tumor-specific transgenes. Herein, positive therapeutic effects for MY-NEOVAX™, personalized neoantigen-enhanced oncolytic adenoviruses, are described for two heavily pretreated end-stage patients, one with high-grade metastatic neuroendocrine carcinoma of the pancreas and the other with colorectal cancer metastatic to the brain, liver and lungs. To date, treatment benefit has exceeded 12 months without dose-limiting toxicities or related serious adverse events and with documented radiologic stabilization and improved performance status.

REPLATINUM Phase III randomized study: RRx-001 + platinum doublet versus platinum doublet in third-line small cell lung cancer

RRx-001 is a cysteine-directed anticancer alkylating agent with activity in a Phase II study in platinum refractory small cell lung cancer. Here, we describe the design of REPLATINUM, an open-label, Phase III trial. 120 patients with previously platinum-treated small cell lung cancer in third line will be randomized 1:1 to receive RRx-001 followed by four cycles of a platinum doublet, and then alternating cycles of RRx-001 and single agent platinum until progression versus four cycles of a platinum doublet. At radiologic progression on the platinum doublet, patients may cross over to the RRx-001 arm. Primary objective: to demonstrate superior progression-free survival in the RRx-001 population. Secondary objectives: to demonstrate superiority for overall survival and objective response rate. Clinical Trial registration: NCT03699956.

ROCKET: A randomized, multicenter phase 2 study of RRx-001 + irinotecan versus regorafenib in 3rd/4th line colorectal cancer

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Background: The purpose of this study was to assess the efficacy of combination therapy with RRx-001, an aerospace-derived macrophage repolarizing agent with epigenetic and vascular normalization properties, plus irinotecan vs. regorafenib plus irinotecan in 3rd/4th line metastatic colorectal cancer that previously received treatment with irinotecan. Methods: Between June 2014 and August 2015, 34 patients were enrolled. Therapy consisted of intravenous administration of RRx-001 at 4 mg once weekly until progression followed by intravenous infusion of irinotecan at 180 mg/m2 on day 1 in a 21-day cycle vs. 160 mg oral regorafenib daily for 3/4 weeks followed at progression, if applicable, by irinotecan 180 mg/m2 on day 1 in a 21-day cycle. Results: The survival follow up for RRx-001 + irinotecan range was approximately 14.5 months (mean 6.0 months, median 5.0 months, standard deviation 4.5 months). The survival follow up for regorafenib range was approximately 10.8 months (mean 4.5 months, median 4.0 months, standard deviation 3.9 months). The median survival time was 8.6 months for RRx-001 + irinotecan and 4.7 months for regorafenib. The median progression free survival was 7.5 months for RRx-001 + irinotecan vs. 1.7 months for regorafenib. In addition, the toxicity profile of RRx-001 + irinotecan was dramatically improved compared with regorafenib. The regorafenib arm was terminated for futility at interim analysis, after which any enrolled patients only received RRx-001 co-infused with an aliquot of autologous blood to evaluate the safety of that method of administration. Conclusions: The results of this trial demonstrate improved efficacy and efficacy of RRx-001 + irinotecan compared with regorafenib in patients with metastatic colorectal cancer. Clinical trial information: NCT02096354.

Pulsed high-dose erlotinib with gemcitabine as second-line therapy for pancreatic adenocarcinoma

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Background: The options for treatment of pancreatic cancer follow progression on first line therapy are limited and associated with significant toxicity. Erlotinib has been approved for treatment of pancreatic cancer in first-line therapy. We conducted a phase I dose-escalation trial of erlotinib in combination with gemcitabine for patients that had failed first-line therapy. Erlotinib was administered by a novel pulse-dose schedule where the drug was given orally for 3 days every two weeks. Purpose: Assess the safety and determine a recommended phase II dose for pulsed high dose erlotinib in combination with gemcitabine for pancreatic cancer, and obtain preliminary data on activity. Methods: Patients with pancreatic cancer that progressed on or after first-line therapy were treated in a dose escalation study with erlotinib at 750 to 2,000 mg daily for three days every two weeks in combination with weekly gemcitabine at 1,000 mg/m2 for three weeks on and one week off. Results: No dose limiting toxicities were encountered and erlotinib-induced rash was mild and transient. Median overall survival was 6.7 months and 12-month overall survival was 27%. Progression free survival but not overall survival was longer in patients who did not previously receive gemcitabine. Rash was not associated with longer survival. Conclusions: The recommended phase II dose is erlotinib 2,000 mg daily for three consecutive days every two weeks in combination with gemcitabine. Tolerability was excellent, and outcomes were better than expected for second-line therapy in pancreatic cancer. Further studies are warranted, both as therapy after first-line and as first-line therapy for patients unable to tolerate more aggressive regimens. Clinical trial information: NCT02154737.

A practical guide to the handling and administration of personalized transcriptionally attenuated oncolytic adenoviruses (PTAVs)

The aim of this review is to provide practical information on the handling, storage, and administration procedures for personalized oncolytic adenoviruses (PTAVs), which have recently entered clinical trials. As described herein, personalized oncolytic viruses refer to transcriptionally attenuated (TA) type 5 adenoviruses that are engineered to carry one or more neoantigenic transgenes derived from patient tumors. Vials of personalized viruses should be stored at -60°C without refreezing after thawing to maintain infectivity. To prevent accidental exposure and transmission, full implementation of universal precautions for preparation, administration, and handling is required. Contaminated materials that come into contact with personalized viruses should be properly disposed of in accordance with local institutional procedures. Severely immunocompromised or pregnant healthcare workers should not prepare or administer personalized viruses or directly contact injection sites. Personalized viruses are administered subcutaneously and intratumorally; however, only subcutaneous injection will be considered in this review. The specific storage, handling, administration, and safety requirements for personalized viruses are easily managed in the context of a clinical trial following the directives from the study protocol.

Case Series: Abscopal Benefit of Surgery in 3 Immunotherapy-Treated Patients With Unresectable Cancer

For all of the optimism that immunotherapy has engendered, the flip side is that 7/10 patients with susceptible tumor types do not respond, while in nonsusceptible tumor types the response rates are significantly lower. In contradiction of the current orthodoxy against surgery in the setting of unresectable disease, we present 3 examples of immunotherapy-treated patients with widespread recurrence who experienced dramatic clinical improvement following debulking/metastasectomy. Taken together with examples from the literature that correlate longer survival with surgical intervention during treatment with immunotherapy, these 3 cases suggest that a new paradigm involving a wider role for surgery in the management of these patients should be explored. Possible mechanisms by which surgery may synergize with immunotherapy and improve outcomes are also discussed.

Brief report: RRx-001 is a c-Myc inhibitor that targets cancer stem cells

The goal of anticancer therapy is to selectively eradicate all malignant cells. Unfortunately for the majority of patients with metastatic disease, this goal is consistently thwarted by the nearly inevitable development of therapeutic resistance; the main driver of therapeutic resistance is a minority subpopulation of cancer cells called cancer stem cells (CSCs) whose mitotic quiescence essentially renders them non-eradicable. The Wnt signaling pathway has been widely implicated as a regulator of CSCs and, therefore, its inhibition is thought to result in a reversal of therapeutic resistance via loss of stem cell properties.

RRx-001 is a minimally toxic redox-active epi-immunotherapeutic anticancer agent in Phase III clinical trials that sensitizes tumors to radiation and cytotoxic chemotherapies. In this article, as a potential mechanism for its radio- and chemosensitizing activity, we report that RRx-001 targets CD133⁺/CD44⁺ cancer stem cells from three colon cancer cell-lines, HT-29, Caco-2, and HCT116, and inhibits Wnt pathway signalling with downregulation of c-Myc.

What's New in SCLC? A Review

A few years ago the answer to the question in the title of this review would have been, "unfortunately not much" or even "nothing", likely eliciting knowing nods of agreement from oncologists. For the last 3 decades, SCLC has been notorious for its lack of progress, as drug after drug, over 60 of them, in fact, including inhibitors of VEGF, IGFR, mTOR, EGFR and HGF has failed and fallen by the wayside due to little or no impact on PFS or OS, while SCLC's cousin, NSCLC, has notched success after success with a spate of targeted treatment and immunotherapy regulatory approvals. However, a paradigm shift or, more appropriately, a 'paradigm nudge' is quietly underway in extensive stage SCLC with a series of agents that in early clinical trials have shown the potential to 'lift the curse' in SCLC, heretofore referred to as "a graveyard for drug development". These agents, constituting the "best of what's new" in SCLC, and discussed in this review following a brief overview of the classification, epidemiology, prognosis and current treatment of SCLC, include checkpoint inhibitors, antibody-drug conjugates, PARP inhibitors, epigenetic inhibitor/innate immune activator, and an inhibitor of RNA polymerase II. Compared to NSCLC, the therapeutic options are still limited but with one or more successes to build momentum and drive long-overdue R&D and clinical investment the hope is that the approval floodgates may finally open.

No patient left behind: The promise of immune priming with epigenetic agents

Checkpoint inhibitors, monoclonal antibodies that inhibit PD-1 or CTLA-4, have revolutionized the treatment of multiple cancers. Despite the enthusiasm for the clinical successes of checkpoint inhibitors, and immunotherapy, in general, only a minority of patients with specific tumor types actually benefit from treatment. Emerging evidence implicates epigenetic alterations as a mechanism of clinical resistance to immunotherapy. This review presents evidence for that association, summarizes the epi-based mechanisms by which tumors evade immunogenic cell death, discusses epigenetic modulation as a component of an integrated strategy to boost anticancer T cell effector function in relation to a tumor immunosuppression cycle and, finally, makes the case that the success of this no-patient-left-behind strategy critically depends on the toxicity profile of the epigenetic agent(s).

Electrolyte disorders with platinum-based chemotherapy: mechanisms, manifestations and management

Platinum chemotherapy, particularly cisplatin, is commonly associated with electrolyte imbalances, including hypomagnesemia, hypokalemia, hypophosphatemia, hypocalcemia and hyponatremia. The corpus of literature on these dyselectrolytemias is large; the objective of this review is to synthesize the literature and summarize the mechanisms responsible for these particular electrolyte disturbances in the context of platinum-based treatment as well as to present the clinical manifestations and current management strategies for oncologists and primary care physicians, since the latter are increasingly called on to provide care for cancer patients with medical comorbidities. Correct diagnosis and effective treatment are essential to improved patient outcomes.

RRx-001 Priming of PD-1 Inhibition in the Treatment of Small Cell Carcinoma of the Vagina: A Rare Gynecological Tumor

Small cell carcinoma of the vagina is rare, so rare in fact that the total number reported in English-language journals is less than 30. Due to this extremely low incidence, no specific treatment guidelines have been established, and most of what is clinically known is derived from a handful of single case reports. However, as befitting its highly aggressive histologic features, which are reminiscent of small cell lung cancer (SCLC), first-line treatment is modeled after SCLC. Herein is reported the case of a 51-year-old African-American patient with metastatic biopsy-proven small cell carcinoma of the vagina that progressed through multiple therapies: first-line cisplatin and etoposide (making it platinum-resistant) and radiotherapy, followed by the tumor macrophage-stimulating agent RRx-001 in a clinical trial called QUADRUPLE THREAT, which per protocol preceded a mandated rechallenge with cisplatin and etoposide. RECIST v.1.1 tumor progression on both RRx-001 and cisplatin/etoposide was accompanied by central necrosis in several of the enlarged lymph nodes and hepatic metastases, which may have been evidence of pseudoprogression, accounting for her ongoing longer-than-expected survival, since the necrotic tissue may have primed the activity of the PD-1 inhibitor. The lack of response to RRx-001 is hypothesized to have correlated with sparse tumor macrophage infiltration, seen on pre- and post-treatment biopsies, since the mechanism of action of RRx-001 relates to stimulation of tumor-associated macrophages.

RRx-001: a systemically non-toxic M2-to-M1 macrophage stimulating and prosensitizing agent in Phase II clinical trials

INTRODUCTION

According to Hanahan and Weinberg, cancer manifests as six essential physiologic hallmarks: (1) self-sufficiency in growth signals, (2) insensitivity to growth-inhibitory signals, (3) evasion of programmed cell death, (4) limitless replicative potential, (5) sustained angiogenesis, and (6) invasion and metastasis. As a facilitator of these traits as well as immunosuppression and chemoresistance, the presence of tumor-associated macrophages (TAMs) may serve as the seventh hallmark of cancer. Anticancer agents that successfully reprogram TAMs to target rather than support tumor cells may hold the key to better therapeutic outcomes. Areas covered: This article summarizes the characteristics of the macrophage-stimulating agent RRx-001, a molecular iconoclast, sourced from the aerospace industry, with a particular emphasis on the cell-to-cell transfer mechanism of action (RBCs to TAMs) underlying its antitumor activity as well as its chemo and radioprotective properties, consolidated from various preclinical and clinical studies. Expert opinion: RRx-001 is macrophage-stimulating agent with the potential to synergize with chemotherapy, radiotherapy and immunotherapy while simultaneously protecting normal tissues from their cytotoxic effects. Given the promising indications of activity in multiple tumor types and these normal tissue protective properties, RRx-001 may be used to treat a broad spectrum of malignancies, if it is approved in the future.

Results from a phase 2b, randomized, multicenter study of GVAX pancreas and CRS-207 compared to chemotherapy in adults with previously-treated metastatic pancreatic adenocarcinoma (ECLIPSE Study)

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Background: GVAX is composed of irradiated, allogeneic pancreatic cancer cells modified to express GM-CSF and induce broad tumor antigen responses. Low-dose cyclophosphamide (CY) is administered with GVAX to inhibit regulatory T cells. CRS-207 is live, attenuated, double-deleted Listeria monocytogenes(LADD) engineered to express mesothelin. CRS-207 boosts T cell responses against mesothelin and stimulates innate and adaptive immunity. In an earlier Phase 2 study in patients with mPDA, CY/GVAX + CRS-207 resulted in a significant improvement in overall survival (OS) compared to CY/GVAX alone. Methods: Patients with previously-treated mPDA were randomized 1:1:1 to receive 2 doses of CY/GVAX + 4 doses of CRS-207 (Arm A), 6 doses of CRS-207 alone (Arm B), or physician’s choice of single-agent chemotherapy (Arm C). Two cohorts were included based on number of prior lines of therapy; the primary cohort (PC) represented those with ≥ 2 prior lines. The primary objective was to compare OS between Arms A and C in the PC. Additional objectives include OS analyses between all treatment arms, safety, tumor responses and immune analyses. Results: 303 patients were enrolled: 213 in the PC and 90 in an exploratory 2nd-line cohort (SC). Common AEs associated with CRS-207 treatment included transient fevers, chills, and nausea. High dropout rates were observed in Arm C prior to treatment (40% in PC, 63% in SC). Clinical trial information: NCT02004262 . Subset and immune analyses, as well as OS data from SC, will be presented at the meeting. Conclusions: The combination of CY/GVAX + CRS-207 did not show a survival benefit over chemotherapy in patients with previously-treated mPDA, although survival of patients receiving CRS-207 alone appeared similar to chemotherapy. The regimens were well tolerated with no new significant safety findings. The high dropout rate in the chemotherapy arm demonstrates a potential challenge for conventional controls in immunotherapy trials. [Table: see text]

A Partial Response to Reintroduced Chemotherapy in a Resistant Small Cell Lung Cancer Patient After Priming with RRx-001

As an exceedingly recalcitrant and highly aggressive tumor type without Food and Drug Administration-approved treatment or a known cure, the prognosis of recurrent extensive stage platinum-resistant/refractory small cell lung cancer (SCLC) is worse than other types of lung cancer, and many other tumor types, given a response rate of less than 10% and an overall survival of less than six months. It was broadly classified into three groups based on the initial response to cisplatin/etoposide therapy, platinum-refractory, platinum-resistant, and platinum-sensitive, extensive stage SCLC inevitably relapses, at which point the only standard options are to rechallenge with the first-line chemotherapeutic regimen in the case of sensitive disease or to start the topoisomerase I inhibitor, topotecan. Sensitive disease is defined by a response to the first-line therapy and a treatment-free interval of at least 90 days, while the definitions of refractory and resistant disease, respectively, are nonresponse to the first-line treatment or relapse within 90 days. As an important predictor of response to the second-line treatment, the clinical cutoff of three months (or two months in some cases) for resistant and sensitive disease, which along with performance status prognostically separates patients into high- and low-risk categories, dictates subsequent management. This case report presents a resistant SCLC patient enrolled on a Phase II clinical trial called QUADRUPLE THREAT (formerly TRIPLE THREAT; NCT02489903) who responded to reintroduced platinum doublets after sequential priming with the resistance-reversing epi-immunotherapeutic agent, RRx-001. In the QUADRUPLE THREAT clinical trial, both during priming with RRx-001 and during sequential treatment with platinum doublets, the patient maintained a good quality of life and performance status.

Confirmatory Trials in the Evaluation of Anticancer Medicinal Products in Man--PFS2: A Measure of Therapeutic Action-At-A-Distance

Overall survival (OS) has emerged as the definitive regulatory "be-all, end-all" for the demonstration of benefit in cancer clinical trials. The reason and the rationale for why this is so are easily appreciated: literally a "test of time," OS is a seemingly unambiguous, agenda-free end point, independent of bias-prone variables such as the frequency and methods of assessment, clinical evaluation, and the definition of progression. However, by general consensus, OS is an imperfect end point for several reasons: First, it may often be impractical because of the length, cost, and the size of clinical trials. Second, OS captures the impact of subsequent therapies, both beneficial (i.e., active) and detrimental, on survival but it does not take into account the contribution of subsequent therapies by treatment arm; the postprogression period is treated as an unknown black box (no information about the potential influence of next-line therapies on the outcome) under the implicit assumption that the clinical trial treatment is the only clinical variable that matters: what OS explicitly measures is the destination, that is, the elapsed time between the date of randomization (or intention to treat) and the date of death, not the journey, that is, what transpires in-between. In long-term maintenance strategies, patients receive treatment in temporally separated but mutually interdependent and causally linked sequences that exert a "field of influence" akin to action-at-a-distance forces like gravity, electricity, and magnetism on both the tumor and each other. Hence, in this setting, a new end point, PFS2, is required to measure this field of influence. This article reviews the definition and use in clinical trials of PFS2 and makes the case for its potential applicability as a preferred end point to measure the mutual influence of individual regimens in long-term maintenance strategies with resensitizing agents in particular.

Partial Response in an RRx-001-Primed Patient with Refractory Small-Cell Lung Cancer after a Third Introduction of Platinum Doublets

Small-cell lung cancer (SCLC), initially exquisitely sensitive to first-line cisplatin/etoposide, invariably relapses and acquires a multidrug chemoresistant phenotype that generally renders retreatment with first-line therapy both futile and counterproductive. This report presents the case of a 77-year-old Caucasian male with extensive-stage refractory SCLC who was restarted on platinum doublets as part of a clinical trial called TRIPLE THREAT (NCT02489903) involving pretreatment with the epi-immunotherapeutic agent RRx-001, and who achieved a partial response after only 4 cycles. The patient had received a platinum drug twice before, in 2009 for a diagnosis of non-small-cell lung cancer (squamous cell carcinoma) and in 2015 for SCLC, suggesting that RRx-001 pretreatment may sensitize or resensitize refractory SCLC patients to first-line chemotherapy.

Immune Reactivity and Pseudoprogression or Tumor Flare in a Serially Biopsied Neuroendocrine Patient Treated with the Epigenetic Agent RRx-001

Neuroendocrine tumors (NETs) are grouped together as a single class on the basis of histologic appearance, immunoreactivity for the neuroendocrine markers chromogranin A and synaptophysin, and potential secretion of hormones, neurotransmitters, neuromodulators and neuropeptides. Nevertheless, despite these common characteristics, NETs differ widely in terms of their natural histories: high-grade NETs are clinically aggressive and, like small cell lung cancer, which they most closely resemble, tend to respond to cisplatin and etoposide. In contrast, low-grade NETs, which as a rule progress and behave indolently, do not. In either case, the treatment strategy, apart from potentially curative surgical resection, is very poorly defined. This report describes the case of a 28-year-old white male with a diagnosis of high-grade NET of undetermined primary site metastatic to the lymph nodes, skin and paraspinal soft tissues, treated with the experimental anticancer agent RRx-001, in the context of a phase II clinical trial called TRIPLE THREAT (NCT02489903); serial sampling of tumor material through repeat biopsies demonstrated an intratumoral inflammatory response, including the amplification of infiltrating T cells, which correlated with clinical and symptomatic benefit. This case suggests that pseudoprogression or RRx-001-induced enlargement of tumor lesions, which has been previously described for several RRx-001-treated patients, is the result of tumoral lymphocyte infiltration.

Statistical analysis of episensitization using transition probability functions and PFS2 for “ROCKET”, a two stage phase II study of RRx-001, a multi-epigenetic agent, investigating resensitization to irinotecan in colorectal cancer

TPS775

Background: The development of resistance to chemotherapies in cancer leads to disease progression resulting in impaired survival. RRx-001, a ROS-mediated DNMT and HDAC inhibitor, may resensitize patients to previously effective, now refractory therapies, improving survival. A randomized two-stage Phase 2 trial of RRx-001 vs regorafenib (ROCKET) is underway to assess the impact of resensitization to irinotecan on overall survival in irinotecan refractory tumors. Transition Probability Functions (TPF) using Markov Chains have previously been used in clinical trials and provide a powerful tool for resensitization analysis. Methods: Patients with metastatic colorectal cancer who previously responded, then progressed on irinotecan-based therapies, with or without bevacizumab, cetuximab or panitumumab and an ECOG PS 0-1 are randomized to receive RRx-001 1x/week or regorafenib until progression or unacceptable toxicity in Stage 1. Patients then advance to Stage 2 to receive irinotecan-based therapies. This trial is designed to detect an increase in median OS of 3 mo., corresponding to a 33% reduction in risk of death. The primary endpoint, overall survival (OS), employs a two-sided log-rank test to compare treatment groups. The hazard ratio and its 95% CI are derived from the Cox proportional hazards model. Kaplan-Meier survival curve estimates are graphically depicted by treatment group. Secondary endpoints include PFS, PFS2 and Transition Probability Functions to address the resensitization hypothesis, KRAS or p53 status dependence. The analysis of PFS2, defined as time to progression (or death) from randomization to progression in Stage 2 (post Irinotecan therapy) is a key secondary endpoint and its analysis uses the standard two-sided log-rank test. TPF estimates will be derived from the Markov Chain transition probability matrix. The study should provide compelling evidence in support of the ability to return to previously beneficial chemotherapy treatment. Recruitment is ongoing. Clinical trial information: NCT02096354.

Ibrutinib + durvalumab (MEDI4736) in patients (pts) with relapsed or refractory (R/R) pancreatic adenocarcinoma (PAC): A phase Ib/II multicenter study

TPS484

Background: PAC is an aggressive disease characterized by poor prognosis and is inadequately treated with available therapies. Ibrutinib is a first-in-class, oral inhibitor of Bruton’s tyrosine kinase (BTK) that was shown to inhibit mast cell degranulation in the PAC tumor microenvironment with subsequent inhibition of tumor cell proliferation, angiogenesis, and collagen deposition (Chang, 2011; Masso-Valles, 2015). Durvalumab, a human IgG1 monoclonal antibody (mAb), binds PD-L1 with high affinity and prevents interaction with PD-1 and CD80 (IC50values of 0.1 nM and 0.04 nM, respectively), facilitating antitumor T-cell responses (Stewart, 2015). Ibrutinib + anti-PD-L1 mAbs inhibited tumor cell growth and led to enhanced anti-tumor immune responses in mouse models (Sagiv-Barfi, 2015). This trial (PCYC-1135; NCT02403271) evaluates the safety and efficacy of ibrutinib + durvalumab in pts with PAC, breast cancer, and non-small cell lung cancer. Study details presented here focus on the cohort of pts with PAC. Methods: Key inclusion criteria include pathologically confirmed PAC, R/R disease (failed ≥ 1 prior systemic therapy), stage III-IV disease, ≥ 1 measurable lesion by RECIST 1.1 criteria, and adequate hematologic, renal, hepatic function. Key exclusion criteria include any history of central nervous system involvement; prior treatment with ibrutinib/BTK inhibitor or treatment with antibodies targeting PD-1, PD-L1, PD-L2, CD137, or CTLA-4; history of allogeneic organ transplant; or treatment with a strong cytochrome P450 3A inhibitor. Primary objectives are safety, tolerability, and efficacy of the combination; secondary objectives include pharmacokinetics and pharmacodynamic assessments of the combination. The phase 1b portion will assess the dose-limiting toxicities (DLTs) and determine the recommended phase 2 dose (RP2D). Ibrutinib will be administered at the standard dose with the potential for dose level reductions if DLTs occur in combination with durvalumab. After RP2D determination, enrollment in phase 2 will occur until a total of 130-160 pts (across all 3 disease cohorts) are treated. Enrollment for phase 1b began in March 2015. Clinical trial information: NCT02403271.

Episensitization: Defying Time's Arrow

The development of cancer is driven by complex genetic and epigenetic changes that result in aberrant and uncontrolled cellular growth. Epigenetic changes, in particular, are implicated in the silencing or activation of key genes that control cellular growth and apoptosis and contribute to transformative potential. The purpose of this review is to define and assess the treatment strategy of “episensitization,” or the ability to sensitize cancer cells to subsequent therapy by resetting the epigenetic infrastructure of the tumor. One important facet is resensitization by epigenetic mechanisms, which goes against the norm, i.e., challenges the long-held doctrine in oncology that the reuse of previously tried and failed therapies is a clinically pointless endeavor. Thus, episensitization is a hybrid term, which covers recent clinically relevant observations and refers to the epigenomic mechanism of resensitization. Among the many formidable challenges in the treatment of cancer, the most inevitable is the development of acquired therapeutic resistance. Here, we present the basic principles behind episensitization and highlight the evidence suggesting that epigenetically mediated histone hypoacetylation and DNA hypermethylation events may reverse clinical drug resistance. The potential reversibility of epigenetic changes and the microenvironmental impact of epigenetic control on gene expression may mediate a return to a baseline state of treatment susceptibility. Episensitization is a novel and highly practical management strategy both to prevent the practice of permanent treatment discontinuation with the occurrence of resistance, which rapidly exhausts remaining options in the pharmaceutical armamentarium and to significantly extend patient survival. Accordingly, this review highlights several epigenetic agents including decitabine, vorinostat, entinostat, 5-azacitidine, oncolytic viruses, and RRx-001.

Phase I study of everolimus, cetuximab and irinotecan as second-line therapy in metastatic colorectal cancer

AIM

To evaluate feasible doses of weekly everolimus and irinotecan given with cetuximab for previously treated metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

Adults with mCRC that progressed after 5-fluorouracil or capecitabine-plus-oxaliplatin were treated using a sequential dose escalation scheme. Dosing decisions were based on the probability of experiencing a dose-limiting toxicity (DLT) during the first two 21-day treatment cycles.

RESULTS

Patients received everolimus 30 mg/week plus irinotecan 350 mg/m2 q3w (n=5; dose A1) or everolimus 30 mg/week plus irinotecan 250 mg/m2 q3w (n=14; dose B1). Among patients evaluable for the maximum tolerated dose, two out of four in A1 and one out of eight in B1 experienced four DLTs. The trial was terminated early based on changes in clinical practice and emerging data on everolimus dosing.

CONCLUSION

The feasible doses of everolimus and irinotecan administered with cetuximab as second-line therapy in mCRC were 30 mg/week and 250 mg/m2, respectively.