Manuscript summary Chronic Lymphoid Leukemia (CLL) Background Genetically engineering T cells Patient treatment history Engineered T cell therapy and results Future applications

Investigators designed a lentiviral vector to express a chimeric antigen receptor to the B Cell CD19 antigen This vector was transformed into the T Cells of a patient with chronic lymphocytic leukemia (CLL). These genetically engineered T Cells were propagated and injected into the patient Despite some severe toxicity due to the amount of cells destroyed by treatment, the patient showed no signs of cancerous cells 10 months after treatment. Porter D, Levine B, Kalos M, Bagg A, June C. Chimeric Antigen Receptor–Modified T Cells in Chronic Lymphoid Leukemia. N Engl J Med 2011; 365:

CLL is a common form of leukemia and is caused when B cells grow out of control CLL is generally considered incurable, however life expectancy after diagnosis is 8 to 25 years Common mutations Deletion of a portion of chromosome 17p. This mutation generally indicates significantly shorter intervals between treatments Deletion of a portion of chromosome 11 Trisomy 12 Deletion of a portion of chromosome 13

A lentivirus vector was used to express a chimeric antigen receptor (CAR) composed of three components: – Antigen recognition domain of an anti-CD19 antibody – Intracellular domain of the CD3-zeta chain – CD137 (4-1BB) signaling domain T cells were collected from the patient by leukapheresis, cryopreserved, and subsequently tranformed with the CAR vector

1996 – patient diagnosed with stage I CLL 2002 – first treatments with two cycles of rituximab plus fludarabine resulting in normalized blood counts 2006 – Patient received four cycles of the same treatment with similar results 2009 (February) – Bone marrow showed persistent infiltration with CLL. Cytogenetic analysis showed that 170 of 200 cells had p53 deletions on chromosome 17p. Treatment with one round of rituximab and bendamustine followed by three rounds of bendamustine alone showed only marginal effectiveness

In December of 2009, T cells from the patient were removed by leukaphoresis and cryopreserved T cells were transduced with lentiviral vector Four days before infusion the patient received chemotherapy to deplete lymphocytes. Three days later the patient showed that 40% of the bone marrow was involved in CLL Treatment with engineered T cells was conducted over 3 consecutive days, with an increasing amount of cells infused each day.

Fourteen days after the initial infusion the patient began to exhibit a fever On day 22 the patient was diagnosed with tumor lysis syndrome and hospitalized for 4 days By day 23 there was no evidence of CLL in the bone marrow CLL Remission remained sustained for the 10 months between treatment and the publication of the manuscript

Comparison of bone marrow biopsy specimens from Day 1 and Day 23 show transition from hypercellular to normal. Analysis of the bone marrow at 6 months shows continued remission

Increased levels of creatinine, LDH, and uric acid correspond to the onset of tumor lysis syndrome

Replacing the anti-CD19 portion of the chimeric antigen receptor with any number of proteins can create genetically engineered T cells capable with any number of applications – Pre-programmed for specific viruses such as HIV, HSV, Hepatitis – Cancer cells expressing specific receptors

Porter D, Levine B, Kalos M, Bagg A, June C. Chimeric Antigen Receptor– Modified T Cells in Chronic Lymphoid Leukemia. N Engl J Med 2011; 365: Kalos M, Levine BL, Porter DL, et al. T cells with chimeric antigen receptors have potent antitumor effects and can establish memory in patients with advanced leukemia. Sci Transl Med 2011;3:95ra73-95ra73 Gross G, Waks T, Eshhar Z. Expression of immunoglobulin-T-cell receptor chimeric molecules as functional receptors with antibody-type specificity. Proc Natl Acad Sci U S A 1989;86: Milone MC, Fish JD, Carpenito C, et al. Chimeric receptors containing CD137 signal transduction domains mediate enhanced survival of T cells and increased antileukemic efficacy in vivo. Mol Ther 2009;17: Irving BA, Weiss A. The cytoplasmic domain of the T cell receptor zeta chain is sufficient to couple to receptor-associated signal transduction pathways. Cell 1991;64: