CENTER OF EXCELLENCE IN IMMUNOLOGY

STEERING COMMITTEE MEETING

SUMMARY MINUTES

April 30, 2007

# CENTER OF EXCELLENCE IN IMMUNOLOGY

**STEERING COMMITTEE MEETING**

April 30, 2007\
3:00--5:00 p.m.

**Bldg. 31, Room 3C11**

**Videoconference to Frederick, Bldg. 549, Café Room**

> **Members present:** Dr. Robert Wiltrout *(Chair)*
>
> Dr. Jonathan Ashwell
>
> Dr. Jay Berzofsky
>
> Dr. Stephen Creekmore *(Adjunct)*
>
> Dr. Ronald Gress
>
> Dr. Crystal Mackall
>
> Ms. Karen Maurey *(Adjunct)*
>
> Dr. Joost Oppenheim
>
> Dr. Marjorie Robert-Guroff
>
> Dr. Steven Rosenberg
>
> Dr. Jeffrey Schlom
>
> Dr. Robert Yarchoan
>
> Dr. Thomas Waldmann
>
> **Members absent:** Dr. Allan Hildesheim
>
> Dr. Diana Linnekin
>
> Dr. Jeffrey Lifson
>
> Dr. Douglas Lowy
>
> Dr. Ira Pastan
>
> Dr. Dale Shoemaker
>
> Dr. Alfred Singer
>
> Dr. Dinah Singer
>
> Dr. Giorgio Trinchieri
>
> Dr. Howard Young
>
> **Guests:** Dr. Petra Delgado
>
> Dr. Laura Hooper
>
> Mr. Victor Lin

######### Handouts

1.  Agenda.

2.  Presentation *"Development of Recombinant Human Interleukin-15 Into
    a cGMP Product."*

overview

The Center of Excellence in Immunology Steering Committee (CEI SC)
convened its monthly meeting on April 30, 2007, at 3:00 p.m. Drs. Steve
Creekmore and Tom Waldmann provided an update on the manufacturing and
developing plans for IL-15. Dr. Robert Wiltrout invited members to
propose CEI-sponsored initiatives similar to the IL-15 project that
could benefit the Immunology community at CCR.

update on the IL-15 project

Dr. Creekmore provided an update on the manufacturing of human IL-15 in
the *E. coli* expression system. The 100-mg production scale has been
achieved, purity issues (aggregation, misfolding) are being resolved,
and stability following multiple freeze/thaw cycles has been
demonstrated. An engineering production run is planned for the
toxicology lot. The intermediate production goal is to produce
100-500 mg per run of purified IL-15 for assay and process development,
formulation/stability studies, and pharmacology/toxicology studies, as
well as the first clinical study.

Dr. Creekmore noted that upstream processing of the material affects
downstream purification strategy, and mentioned the challenges for
scale-up production: Fermentation strategies to increase yield may also
increase impurities and inclusion bodies concentrate significant amounts
of misfolded product but also contain host cell impurities. A sizing
step before refold increases purity of denatured IL-15; however,
misfolded, oxidized, or reduced IL-15 coming out of the refold is
difficult to remove and, therefore, redox conditions must be optimized
during the refold step. Dr. Creekmore added that technology transfer
from Drs. Waldmann and Perera laboratories is complete and the
characterization assays are proceeding as development progresses.
Importantly, an MTS-dye based proliferation assay is available for
measuring bioactivity of recombinant human IL-15. He cautioned that
immunogenicity is a significant concern in the clinical setting, due to
autoimmunization against self IL-15 or to amplified response to
contaminants (e.g., host cell proteins) in the product.

With respect to the timeline, Dr. Creekmore explained that the
engineering production run at scale is projected for Q2 2007; production
of the toxicology lot for non-human primate studies for Q3 2007; and GMP
production (100-200 mg lot) for Q4 2007, in preparation for the IND
filing for Dr. Waldmann's studies. Additional GMP lots at same or larger
scale for NIAID studies are projected for 2008.

Dr. Waldmann added that his group is designing the preclinical and
clinical studies, so that they can be conducted as soon as the material
is available. The toxicology study in *Rhesus* monkeys has already been
approved by the Animal Care and Use Committee. Dr. Waldmann distributed
a draft of the clinical trial proposal for review by CEI SC members. He
is scheduling a "pre- pre-IND" meeting with the FDA to discuss the
clinical development strategy for human IL-15. Although IL-15 will
initially be tested as single agent, Dr. Waldmann envisions that it may
be useful in combination with other interleukins and immunomodulatory
drugs.

Dr. Waldmann added that NIAID is interested in producing IL-15 in
mammalian cells to avoid immunogenicity. However, previous attempts by
academia to produce IL-15 in a mammalian expression system were
unsuccessful and resulted in very low yield. Dr. Waldmann clarified that
he has seen no toxicities thus far in animal studies with IL-15. The CEI
SC discussed whether the toxicology study with human IL-15 in monkeys
would be relevant, as one would expect that monkeys are more likely to
develop immunogenicity against human IL-15 than human subjects. This
issue will be discussed with the FDA.

The meeting adjourned at 4:35 p.m.

**Next Meeting: June 18, 2007**

**Location: Not yet confirmed**