August 22, 2014


1. DAMPs. Following up on my Damage-Associated Molecular Patterns, and Immunogenic Cell Death (August 21, 2014) news item, I'm curious (fascinated) by PV-10's potential role in immunogenic cell death, and thus the release and surface expression of damage-associated molecular patterns ("DAMPs"). DAMPs " the dying tumor cell with innate immunity, culminating in adaptive anticancer memory responses."

The recent paper by Panzarini et al. (2014), Rose Bengal Acetate PhotoDynamic Therapy (RBAc-PDT) Induces Exposure and Release of Damage-Associated Molecular Patterns (DAMPs) in Human HeLa Cells, observed that key DAMPs -- ATP, HSP70, HSP90, HMGB1 and CRT -- were exposed and/or released after treatment of cell lines with Rose Bengal acetate and photodynamic therapy. I understand this work involved using PDT and a functional RB derivative, and was carried out on cell lines; however, what interests me about it is the study's goal, which was to determine if RB could trigger apoptosis and autophagy -- cell death -- and thus expose and/or release pivotal DAMPs.

Very interestingly, in my view, the researchers also noted their data represented the fourth demonstration of the exposure of the HSP90 DAMP by indication and third demonstration by drug compound: "In fact, exposure of HSP90 was shown only in lung cancer [36] and myeloma [37] treated with Bortezomib and in bladder cancer cells treated with capsaicin [38]." Bortezomib is a proteasome inhibitor (Millennium Pharmaceuticals [Velcade]/Venus Remedies [Cytomib]). Capsaicin is a neurotoxin and active component of chili peppers.

Moffitt previously showed PV-10 (Rose Bengal) in their murine model work released HMGB1.

2. Innate and Adaptive Immunity. As I wrote above, DAMPs, or their impact once exposed and/or released, form a bridge between the body's innate and adaptive immune systems (or non-specific and specific, respectively). See my blog post PV-10 is not bigger than Mother Nature for a discussion of the immune system; "The immune system protects organisms from infection with layered defenses of increasing specificity."

In 1994, "[t]wo papers appearing in the same year presaged the deeper understanding of innate immune reactivity, dictating the subsequent nature of the adaptive immune response. The radical-mediated reperfusion injury-was seen to contribute to the process of innate and subsequent adaptive immune responses. The second...suggested the possibility that the immune system detected "danger", through a series of what we would now call damage associated molecular pattern molecules (DAMPs), working in concert with both positive and negative signals derived from other tissues." {Underlined emphasis is mine}
  • Land W, Schneeberger H, Schleibner S, et al. (January 1994). "The beneficial effect of human recombinant superoxide dismutase on acute and chronic rejection events in recipients of cadaveric renal transplants." Transplantation 57 (2): 211–7.
  • Matzinger P (1994). "Tolerance, danger, and the extended family." Annu. Rev. Immunol. 12: 991–1045.
I've written that PV-10 harnesses the immune system, rather than restraining, blocking, manipulating, etc. parts of it. Note that Chen & Mellman (2013) title step 3 of their cancer immunity cycle illustration "Priming and activation." {Underlined emphasis is mine}

3. It's A Small World. The authors of the RBa-PDT paper come from Italy's University of Salento, and do not appear to have any disclosures related to Provectus. While the company has engaged certain principal investigators and their respective hospitals in Australia and the United States, as well as Moffitt Cancer Center, there is a body of work from researchers espousing Rose Bengal's potential as a cancer therapeutic who are currently or not at all unaffiliated (or appear to be unaffiliated) with the company. They are, among others (representative papers below):
4. Amgen's talimogene laherparepvec ("T-Vec"). Related to Amgen's T-Vec, the FDA announced a November 6th advisory committee ("AdComm") meeting (Cellular, Tissue and Gene Therapies Advisory Committee) to discuss the draft guidance for industry entitled "Design and Analysis of Shedding Studies for Virus or Bacteria-Based Gene Therapy and Oncolytic Products." Does this bode well or poorly for T-Vec in regards to its ease of administration and use, or lack thereof?

5. Info. An interview with Peter formed the basis for today's Seeking Alpha article Provectus' Latest Developments Spark Investor Interest -- CFO/COO Culpepper Explains Why. Of note to me was his answer to the interviewer's question "What is the anticipated market trajectory for PV-10?"
Peter: "We anticipate PV-10 phase 3 for melanoma to be one path for PV-10 approval. We anticipate also combining PV-10 to treat patients with disease inaccessible to direct injections. We also anticipate treating primary liver cancer patients in an upcoming randomized phase 2 study and seeking an expedited approval path in that important indication as well."
Taking this response at face value would suggest the upcoming (anticipated) liver Phase 2 trial would be for primary liver cancer (hepatocellular carcinoma), and not include cancers metastatic to the liver. A subsequent or concurrent study might examine this aspect of liver cancer, but the contemplated Phase 2 trial would not, or so it seems to me. Liver cancer of course is a very large unmet need in Asia. One would hope Eric garnered the feedback he required [from his recent Asia trip] to finalize and file the liver Phase 2 trial protocol.

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