Magnetic resonance imaging of RRx-001 pharmacodynamics in preclinical tumors.

RRx-001 is an anticancer agent that subjects cancer cells to reactive oxygen/nitrogen species (ROS/RNS) and acts as an epigenetic modifier. We have used a thiol-bearing MRI contrast agent, Gd-LC7-SH, to investigate the pharmacodynamics of RRx-001 in CHP-100 Ewing's Sarcoma, HT-29 colorectal carcinoma, and PANC-1 pancreatic carcinoma xenografts in SCID mice. Binding of Gd-LC7-SH to the Cys residue on plasma albumin prolongs retention in the tumor microenvironment and increases tumor enhancement on MRI.

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.

The immunomodulatory anticancer agent, RRx-001, induces an interferon response through epigenetic induction of viral mimicry.

Background: RRx-001, a dinitroazetidine derivative, is a novel anticancer agent currently in phase II clinical trials. It mediates immunomodulatory effects either directly through polarization of tumor associated macrophages or indirectly through vascular normalization and increased T-lymphocyte infiltration. With multiple additional mechanisms of action including upregulation of oxidative stress, depletion of GSH and NADPH, anti-angiogenesis and epigenetic modulation, RRx-001 is being studied as a radio- and chemo-sensitizer to resensitize tumors to prior therapy and to prime tumors to respond to radiation, chemotherapy and immunotherapy in combination therapy studies.

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

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.

Conversion of Platinum-Etoposide-Resistant to Sensitive SCLC after Treatment with the Epi-Immunotherapeutic RRx-001: A Case Report.

Background: The response to first-line platinum doublets (cisplatin/etoposide) in small-cell lung cancer (SCLC) predicts the probability of subsequent response to second-line therapy. In general, the longer-lived the responses in first line, the better the outcome in second line, with the opposite prognosis for shorter-lived responses. Resistant SCLC is defined as relapse within 90 days of platinum-doublet treatment, and predictably correlates with shortened survival compared with sensitive disease, defined as relapse after 90 days.