Replies to post #17823 on NorthWest Biotherapeutics Inc (NWBO)

[flipper44]

The data indicates Direct works.

Since the DCVax-Direct phase I trial started, some posters here voiced legitimate concerns regarding Direct's mechanism of action.

After the following phase 2 DCVax-Direct abstract release by UCLA, I suggest many questions are now being addressed. I expect this DCVax-Direct phase 2 trial will be confirmed by data that will come (sooner or later) from the MDAnderson DCVax-Direct phase 1 trial.

Let's go over some of the points below and how they address prior concerns. The abstract and Link are included below this analysis.

A.

The injection consists of autlogous DCs activated with bacillus Calmette Guerin (BCG) and interferon (IFN)-gamma. Culture with BCG and IFN-gamma activates DCs, upregulating cell surface proteins involved in antigen presentation and T cell stimulation.

Discussion: A persons own Dendritic Cells are partially matured, activated and their cell surface proteins are unregulated by:
i. BCG, which is a vaccine against tuberculosis that is prepared from a strain of the attenuated (virulence-reduced) live bovine tuberculosis bacillus, Mycobacterium bovis, that has lost its virulence in humans by being specially subcultured in a culture medium, and
ii. Interferon, FNy, or type II interferon, is a cytokine that is critical for innate and adaptive immunity against viral, some bacterial and protozoal infections. IFNy is an important activator of macrophages, and in this case, dendritic cells.
The keys here are that 1. the attenuated bacteria and interferon are used ex-vivo (outside the body) to partially mature the Dendritic cells. Instead of directly injecting both of these immune inducing factors directly into the body, DCVax-Direct uses a "smart-bomb" delivery system to enhance efficacy while decreasing side effects these treatments can sometimes otherwise have if BCG and/or Interferon were injected directly. 2. This process facilitates up-regulation of cell surface proteins to enhance Dendritic Cell presentation to the t-cells of not only tumor antigens (which will be introduced to the DCs after tumor injection), but indeed, BCG antigens as well. This double expression of BCG and tumor antigens strengthened by Interferon up-regulation creates a very powerful immune response (side-effect is often fever (t-cell proliferation) and beneficial inflammation within the tumor (t-cell infiltration)). 3. The partially matured DC state prior to injection will greatly enhance both tumor antigen/biomarker uptake and even facilitate expression to the t-cells after full maturation.

B.

We hypothesize that the vaccine creates an inflammatory response, and exposure of PBMCs to BCG will cause T cell activation and proliferation. Luminex technology was used to evaluate cytokine levels in patient serum.

UCLA took the initial hypothesis that the vaccine works by causing an inflammation response within the tumor, and additionally lymphocytes in the lymph system, when exposed to BCG expressing Dendritic Cells, will start their T-cell metamorphosis and proliferation, these T-cells would then respond to the inflammatory site at the tumor caused by the initial vaccine inoculation. Note, as of yet the hypothesis does not include the suggestion that the t-cell activation and proliferation is simultaneously facilitated by the DC expression of tumor antigens that are also on the DC surface along with BCG.

C.

The data suggest that treatment with DCVax Direct promotes an inflammatory response that can decrease tumor burden through upregulation of proinflammatory cytokines. Activation and proliferation of lymphocytes exposed to BCG suggest that DCs are presenting BCG and likely tumor antigens to patient T cells allowing for a targeted immune response.

Here is the tentative home run. The data suggest that not only is the t-cell responding to the BCG fragments During DC presentation to the T-cells, but the data also suggest the "targeted immune response" is also brought on by DC-presentation of the tumor antigens to the T-cells.

The breakthrough in any immune therapy is to get the bodies immune defense system to recognize tumor cells. A Dendritic Cell trumps all other immune cells in effectively activating, proliferating and targeting t-cells.

There is much this abstract leaves out. The size of the trial is not known. The enhancement and cyclical nature of the inflammation and targeting process over time, etc.

However, here is what I think we can also safely assume. The patient results in this UCLA trial were collected after 16 weeks. In the phase 1 trial at MDAnderson, all patients who received 16 weeks of therapy, 9 of 9, responded.

One of the best posters (there are a few others) to grace this board was MolBio. One of his main (very legitimate) concerns, if not his primary concern, was tumor DC-escape after injection. This abstract must alleviate his concerns somewhat. Other very intelligent posters on this board voiced several things to watch as results came in.

As more Direct data gets released, I hope to hear from these far more knowledgeable posters.

UCLA: DCVax-Direct Abstract

sttp.healthsciences.ucla.edu/abstract/sttp-abstract-current?abstract_id=2455

Short Term Training Program Student Abstracts


T Lymphocyte Activation and Proliferation with BCG Stimulation of Patients Receiving Dendritic Cell Immunotherapy: A Phase II DCVax-Direct Trial
Jeffrey Lin, Joseph Antonios, Sylvia Odesa, Horacio Soto, Robert M Prins, Linda M Liau
695 Charles E. Young Drive South Gonda 1554 Los Angeles, CA 90095

DCVax-Direct is an autologous cellular immunotherapy involving intratumoral injection to solid tumors as an adjuvant traditional therapies. The injection consists of autlogous DCs activated with bacillus Calmette Guerin (BCG) and interferon (IFN)-gamma. Culture with BCG and IFN-gamma activates DCs, upregulating cell surface proteins involved in antigen presentation and T cell stimulation. Patient peripheral blood monocytes (PBMC) and serum were collected at day 0, week 8, and week 16 before each vaccination. We hypothesize that the vaccine creates an inflammatory response, and exposure of PBMCs to BCG will cause T cell activation and proliferation. Luminex technology was used to evaluate cytokine levels in patient serum. PBMCs were labeled with Cell Proliferation Dye (CPD) and cultured with inactivated BCG, and T cell proliferation was assessed using fluorescent target array technology. Levels of proinflammatory cytokines were higher and anti-inflammatory cytokines were lower in serum collected at later time points. CD4+ and CD8+ T cells exposed to BCG showed increased proliferation in patient PBMCs collected at later time points. The data suggest that treatment with DCVax Direct promotes an inflammatory response that can decrease tumor burden through upregulation of proinflammatory cytokines. Activation and proliferation of lymphocytes exposed to BCG suggest that DCs are presenting BCG and likely tumor antigens to patient T cells allowing for a targeted immune response.

Submitted by [e-mail], under the supervision of Linda, Liau M.D. Ph.D., submited on July 24, 2014