Scott Caroen

The war on cancer: a military perspective

Actually it has not quite happened yet, but almost imperceptibly, by degrees, we are learning to live with cancer. The “War on Cancer,” although generally successful in the pediatric population, has gradually been replaced with a kinder, gentler treatment paradigm that strives to contain and maintain with stalemate over checkmate, a strategy that may literally constitute the path to least resistance. The purpose of this review is (1) to critically examine the War on Cancer as a powerfully evocative metaphor that is directly responsible for a counterproductive and even potentially dangerous war-like cell-kill treatment paradigm, (2) to suggest that a reframing of this metaphor in less retaliatory and aggressive terms along with a shift in clinical practice from a maximalist to a minimalist strategy is more appropriate to the treatment of cancer, and (3) to draw on examples from the military sector as points of reference and comparison that closely parallel the three therapeutic “control and containment” strategies discussed in this review: (1) “Optimox-like” trial designs, (2) epigenetic modulation, and (3) metronomic dosing.

Flushing Out Carcinoid Syndrome: Beneficial Effect of the Anticancer Epigenetic Agent RRx-001 in a Patient with a Treatment-Refractory Neuroendocrine Tumor

Neuroendocrine tumors (NET) are a heterogeneous group of neoplasms defined by the presence of cells with secretory granules and the potential to produce and release high levels of vasoactive peptides into the circulation, leading to severe flushing and diarrhea, which may adversely affect quality of life. This report presents the case of a 64-year-old man with chronic refractory diarrhea due to pulmonary NET treated with the experimental anticancer agent RRx-001 in a phase II trial called TRIPLE THREAT with subsequent resolution of his diarrhea.

Whole brain radiotherapy and RRx-001: Two partial responses in radioresistant melanoma brain metastases from a phase I/II clinical trial: A tite-crm phase I/II clinical trial

BACKGROUND: Kim et al. report two patients with melanoma metastases to the brain that responded to treatment with RRx-001 and whole brain radiotherapy (WBRT) without neurologic or systemic toxicity in the context of a phase I/II clinical trial. RRx-001 is an reactive oxygen and reactive nitrogen species (ROS/RNS)-dependent systemically nontoxic hypoxic cell radiosensitizer with vascular normalizing properties under investigation in patients with various solid tumors including those with brain metastases. SIGNIFICANCE: Metastatic melanoma to the brain is historically associated with poor outcomes and a median survival of 4 to 5 months. WBRT is a mainstay of treatment for patients with multiple brain metastases, but no significant therapeutic advances for these patients have been described in the literature. To date, candidate radiosensitizing agents have failed to demonstrate a survival benefit in patients with brain metastases, and in particular, no agent has demonstrated improved outcome in patients with metastatic melanoma. Kim et al. report two patients with melanoma metastases to the brain that responded to treatment with novel radiosensitizing agent RRx-001 and WBRT without neurologic or systemic toxicity in the context of a phase I/II clinical trial.

RRx-001-Induced Tumor Necrosis and Immune Cell Infiltration in an EGFR Mutation-Positive NSCLC with Resistance to EGFR Tyrosine Kinase Inhibitors: A Case Report

We present the case of a 49-year-old male with metastatic epidermal growth factor receptor (EGFR) mutation-positive adenocarcinoma of the lung that continues to outlive stage IV diagnosis of non-small cell lung cancer after treatment with RRx-001, an experimental anticancer agent with epigenetic and immunologic activity, in the context of a phase II clinical trial called TRIPLE THREAT. Currently, no adequate treatment options exist for patients with EGFR mutation-positive tumors who have failed a 1st-generation tyrosine kinase inhibitor (erlotinib or gefitinib) treatment and do not develop a resistant mutation. Biopsy of a large pancreatic metastasis after RRx-001 demonstrated extensive necrosis with CD3+ and CD8+ immune cell infiltration that appears to correlate with prolonged survival despite end-stage disease. These results suggest that the mode of action of RRx-001 is related to immune stimulation in addition to epigenetic inhibition.

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.

RRx-001 in Refractory Small-Cell Lung Carcinoma: A Case Report of a Partial Response after a Third Reintroduction of Platinum Doublets

RRx-001 is a pan-active, systemically nontoxic epigenetic inhibitor under investigation in advanced non-small cell lung cancer, small-cell lung cancer and high-grade neuroendocrine tumors in a Phase II clinical trial entitled TRIPLE THREAT (NCT02489903), which reexposes patients to previously effective but refractory platinum doublets after treatment with RRx-001. The purpose of this case study is first to report a partial response to carboplatin and etoposide in a patient with small-cell lung cancer pretreated with RRx-001, indicating episensitization or resensitization by epigenetic mechanisms, and second to discuss the literature related to small-cell lung cancer and episensitization.

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 to carboplatin in an RRx-001 pretreated patient with EGFR-inhibitor-resistance and T790M-negative NSCLC.

Few therapeutic options are available for T790M-negative non-small cell lung cancer (NSCLC) after failure of primary epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and chemotherapy. This report presents the case of a 71-year-old Asian female never smoker with EGFR mutated T790M negative non squamous cell lung cancer (NSCLC) pre-treated with the experimental epi-immunotherapeutic agent, RRx-001, that re-responded to single agent carboplatin after failure of platinum doublets, TKIs, pemetrexed and nivolumab. The management of advanced EGFR mutation-positive NSCLC is briefly reviewed herein and the emerging paradigm of episensitization, which contradicts the long-standing and widely accepted tenet about the immutability of resistance and the futility of therapeutic rechallenge, is introduced as a strategy to avert treatment failure and thereby stave off deterioration and death.

A Review of Two Promising Radiosensitizers in Brain Metastases: Rrx-001 and 2-Deoxyglucose

The origin of the common phrase “your name is mud” may derive from the ordeal of 19th century physician, Dr. Samuel Mudd, who was perhaps wrongly convicted of conspiracy in the assassination of President Abraham Lincoln. Mudd’s crime may have only been bad luck: Lincoln’s assassin, John Wilkes Booth, allegedly previously unknown to the doctor, had broken his leg and happened across Mudd who, unwisely, as it turned out, set the fracture, and his own subsequent fate, which included life imprisonment with hard labor, making him a potential victim of circumstance rather than the perpetrator of a crime. Mudd’s grandson, also a physician, tried unsuccessfully to clear his grandfather’s widely reviled name, which as a result has remained, both literally and figuratively, Mudd. This historical analogy highlights the important point that radiosensitizers as a class have been ignored rather than adored due to their failed reputation. Hence, in the field of radiation oncology, the “your name is mud” expression applies to radiation sensitizers, which from hyperbaric oxygen and the nitroimidazoles, to motexafin gadolinium, tirapazamine and efaproxiral have generally overpromised and under delivered with respect to survival treatment benefits in multiple different indications. However, newer non-toxic radiosensitizers on the horizon such as the antienergetic epigenetic redox modulator, RRx-001, that will start a Phase 2 clinical trial with concurrent whole brain radiotherapy (WBRT) in subjects with brain metastases, may finally validate the underlying promise and unrealized potential of these agents. The successful treatment of brain metastases is at least a four-hurdle process involving penetration, retention, selectivity and toxicity. This article will review the mechanism of the radiosensitizers, RRx- 001, and 2-deoxyglucose, as examples or “role models” for therapies that theoretically are able to overcome these substantial in vivo obstacles to successfully treat brain metastases. It is the thesis of this review that new radiosensitizers are urgently needed and their poor reputation should be overcome.