Matt Gethers/20.380 HIV Project/Design Pitch

Design Pitch

Outline

Design (Rob and Matt)

• One problem with HIV treatment is the need to take expensive drugs all your life. Even if we couldn't eliminate the virus from the body completely, controlling viremia at the current benchmark but with less effort on the part of the patient and provider would be a huge improvement.
• Plan is to introduce a permanent viral sink to patients.
  • Rather than trying to inhibit a part of the viral lifecycle through a drug, allow HIV to infect cells, but we choose the target.
  • Functionalize the membranes of RBCs with CD4 and cytokine co-recpetors to mediate infection by HIV.
  • Upon fusion with the RBC, there is no genome in which to integrate or transcriptional/translational machinery.
  • RBC acts as "dead end" from which virus cannot emerge.
• We want this treatment to remain in the body permanently, so we will collect hematopoetic progenitors from the blood stream, transfect CD4 and chemokine receptors under the control of promoters active during differentiation using a lentiviral vector. These cells will then be re-introduced to the patient where they will expand and act as a permanent source of viral sinks.

Benchmarks (Yi)

• How low would the viral titer have to be in order to match current treatments (AZT)?

Modeling (Steph)

• What processes might we want to model to determine if this project is worth taking forward?
  • Will want to test Yi's benchmark for efficacy (can we get viral titer this low).
  • Differentiation rate, Death/clearance rate, probability of infection of RBC as opposed to T-cell,selection.

In Vitro (Courtney-face)

• In vitro tests for efficacy?

In Vivo (Jessie)

• Animal models?

IP (David)

• Previous work:
  • Europoean Patent No. EP0298280: Animal derived cell with antigenic protein introduced therein (1994), assignee is "HAPGOOD, C.V., a Netherlands Antilles Limited Partnership"
    • http://www.freepatentsonline.com/EP0298280.html
    • Basically same as US patent below
  • US Patent No. 5677176: Animal derived cell with antigenic protein introduced therein (1997)
    • http://www.google.com/patents?id=PAwpAAAAEBAJ&output=html
    • US version of Sheffield Medical Technologies from article (same title as claimed European patent) although Sheffield isn't mentioned anywhere
    • Claims an engineered RBC with CD4 on its surface, however claimed use is to encourage fusion of engineered RBC with HIV infected cells via syncytium formation
    • Engineered RBCs or liposomes contain a cytotoxic agent
    • Mechanism: infected cells will have gp120 on surface, which binds CD4 and allows for cell fusion with anything CD4+, which then kills both cells either via its cytotoxic load or splenic filtering of RBCs
    • Important: patent does not discuss any form of genetic engineering - they plan to incorporate CD4 into target RBCs basically by manually mixing concentrated CD4 and RBCs
    • Patent briefly mentions our "viral sink" idea (page 7, under "Clinical Use"), but this isn't in the claims and the authors say the syncytia formation is "more important"
  • US Patent No. 7462485: Modified erythrocytes and uses thereof (December 2008)
    • http://www.freepatentsonline.com/7462485.html
    • Inventor is Lawrence F. Glaser, who may be associated with ViraLogic Technology (as of 2002) but no record of this company exists anywhere
    • This patent basically covers our idea to the tee, almost
    • Focuses on a final treatment involving injection of RBCs, not progenitors
    • Mentions using hematopoietic cells, but unclear whether that would cover our application
    • Claim of interest: "20. A human hematopoietic progenitor cell comprising a recombinantly-produced sequence encoding CD4 or an HIV coreceptor." (Note: this claim was only on the application, and disappeared from the approved version)

• How would we go about securing a patent/starting a company?
  • License the Glaser patent if we think it's needed?

Script

Yi

• [Slide 1 – Intro]

Good morning. My name is Yi Wang, my group members are Matt Gethers, Rob Warden, Stephanie Nix, Courtney Lane, Jessie Wang, and David Ying.

We are here today to present to you a novel treatment for HIV infection. Using engineered hematopoietic stem cells, we will inject into HIV patients a self-replicating pool of red blood cells engineered to act as viral sinks, depleting viral load.

• [Slide 2 – Current Treatments]

Current techniques for treating HIV, such as nucleoside analogues and reverse transcriptase inhibitors, decrease the viral load of HIV to less than 50 virions/mL, delaying the onsets of AIDS for potentially many years.

• [Slide 3 – maybe a graph of developed vs. developing?]

In developed countries, like the United States, where approximately 1% of the population is affected, HIV treatment involves tens of thousands of dollars per year spent on these pills, which must be taken several times a day.

In developing countries, most notably those in sub-Saharan Africa (where up to 30% of the population is affected), treatment is rare due to cultural stigma against HIV, inability to pay for drugs, and noncompliance with drug regimens.

A new therapy for HIV is necessary which costs less and requires fewer treatments – ideally, only one.

Matt

-put the final diagram in the slide show here somewhere

Rob

-make upregulation/down regulation more interesting (maybe a diagram of a cell?)

Steph

Hi, I'm Stephanie, and I'll be talking about how we plan to model the dynamics of the system. The two things we would most like to know at any time in the body are the erythrocyte concentration and the concentration of HIV virions. We would also like to know the concentration of T-cells and other cells that HIV infects, but only as it relates to the previous two.

The number of engineered RBCs depends on the birth rate and the death rate. The birth rate is dependent on the number of progenitors that we add to the body and the net differentiation rate into the final product. The net differentiation rate depends on the number that we expect to differentiate, were they normal RBCs, minus the fail rate due to mutations that we've made to the stem cells. The death rate is dependent on the rate at which the spleen filters the engineered RBCs out of the bloodstream. Once we have the number of RBC sinks, we can calculate the concentration in the bloodstream and the concentration relative to the number of normal RBCs in the system.

The number of HIV also has a number of variables factoring into the birth and death rates. The birth rate depends on the rate of infection of T-cells, which depends on the T-cell population, and the rate at which HIV becomes latent in the host cell. The death rate depends on the rate at which HIV becomes inviable due to an accumulation of mutations that are not beneficial to the virus and the ratio of the infection of RBCs relative to T-cells.

Courtney

• [Slide – In Vitro Tests]

Before we inject our treatment into an animal or person, we are going to want to perform in vitro tests.

To confirm that our engineered cells are expressing what we want to express, we will do genomic testing on the hemopoetic stem cells and proteomic testing on the differentiated erythrocytes. Next, we will make sure the red blood cells effectively fight off infection. Finally, we’ll find the ideal ratio of engineered erythrocyte to T cell by performing co-culture experiments.

Jessie

• [Slide - In Vivo Tests]

Following the various in vitro assays, we will need to conduct in vivo experiments in animal models before we can proceed onto clinical trials.

The key points we'll be looking at are:

1. Is the treatment safe in vivo? Are there any off target effects?
2. Does the treatment lower viral titer? By how much?
3. What is the optimal number of Hemapoietic Stem Cells we need to inject?

One animal model that could potentially work very well is the pig-tailed macaque. Not only do these macaques have HSCs that are similar to those of humans, the animals can also be infected by a human-simian hybrid virus that has a 95% similarity with HIV-1.

David

-The ‘holy shit someone already patented it’ needs a better spin (emphasize how we’re doing it differently by injecting the stem cells)

• [Slide - IP]

Hi, I’m here to talk about the intellectual property issues surrounding our idea of a red blood cell HIV trap. There are basically two patents that may be relevant to our design, and here is the first one.

The 1997 patent dealt with red blood cells engineered to have CD4 on their surface. While this may seem similar to our idea, their idea revolved around manually inserting CD4 into the membrane, and that differs from our idea which uses genetic engineering to introduce CD4 into erythrocytes. Their patent also differs in its proposed mechanism. They wanted their red blood cells to fuse with HIV-infected cells to form what are called syncytia. The red blood cell cytotoxic load is then released into the infected cells, killing both cells.

• [Slide - Glaser patent]

The second patent, which I’ll call the Glaser patent, is much closer to our idea. It was issued just a few months ago, to a sole inventor who we do not believe is linked to any company. His patent covers the use of erythrocytes genetically modified with CD4 and coreceptors to entrap HIV virions. One difference between our idea and this patent is that in our design, we plan to inject hematopoietic stem cells into patients, which will then differentiate into red blood cells, whereas the Glaser patent addresses directly injecting red blood cells. As far as we know, Mr. Glaser has not licensed his patent to anyone, so if we were to go forward and create a company with this idea, we would probably have to license this patent from him.

• [Slide - Summary]- unless someone wants me to write it out, I don't think I'm gonna write out what to say for the summary slide...yea