TNT/NHS76+IL2 Immunocytokines: Merck/Ger, Medipharm etc
At the very least, these entities involved:
1. Merck KGaA of Darmstadt, Germany
2. EMD-Lexigen Research Center, Billerica, MA (Stephen Gillies)
3. Cancer Therapeutics, Inc. (Los Angeles, CA)
4. MediBiotech, Inc. (Los Angeles, CA)
Evidence:
AACR Sun. Mar28, 2004 8-12:00pm
“Engineering of an IL-2 immunocytokine with very low toxicity that retains potent anti-tumor activity in immune competent and immune deficient mouse tumor models”
aacr04.agora.com
Stephen D. Gillies, Yan Lan, Scott Lauder, Beatrice Brunkhorst, Yaping Sun, Kin-Ming Lo. EMD-Lexigen Research Center, Billerica, MA
Poster Session: Lymphokines, Cytokines, and Growth Factors in Tumor Immunity I
Abstract #654:
The use of IL-2 for cancer therapy has been limited by its side effect profile that primarily includes effects in the vascular compartment such as vascular leak syndrome and hypotension. Many theories have been proposed to explain the mechanism of IL-2 toxicity including direct binding to endothelial cells as well as over-stimulation of intermediate affinity IL-2 receptor (IL-2R) bearing cells (e.g. NK cells) in the bloodstream. In our studies of IL-2 toxicity we have identified a specific IL-2 mutant, D20T, which has little selectivity for high over intermediate affinity IL-2 receptors as a free IL-2 molecule but which has profound selectivity when it is fused to the carboxyl terminus of an antibody to form an immunocytokine. Measurements in vitro show it to have near normal biological activity using T cell lines expressing the high affinity IL-2R but little or no activity using lines expressing only the intermediate IL-2R. This mutation also removes a sequence motif proposed earlier to resemble a binding site for endothelial cells found in many bacterial exotoxins. Surprisingly, this mutation within IL-2 had a detrimental effect on the circulating half-life of the immunocytokine that could only be reversed by removing the N-linked glycosylation site within the IgG constant region (CH2 domain). The final molecule was engineered using the V regions from a human antibody, NHS76, with high affinity for the necrotic core of solid tumors, thus allowing for selective targeting of this modified IL-2 to virtually any tumor with necrosis. Our in vitro studies with this molecule show that the binding to necrotic tissue is mediated through its high affinity for single or double-stranded DNA, despite original reports that the NHS76 antibody recognized DNA-histone complexes. Studies in several mouse tumor models demonstrate that this immunocytokine, NHS-IL2(D20T), is extremely well tolerated in immune competent mice and retains most of its anti-tumor activity against established metastases. It also retains significant anti-tumor activity in immune deficient SCID mice lacking functional T cells, although somewhat higher doses are required to achieve equivalent effects. These results suggest additional effector cells expressing high-affinity IL-2R, besides T cells, are functioning in these tumor models. They also show that small metastatic tumors can be targeted using an immunocytokine with specificity for a necrotic marker such as DNA.
Presenter: Stephen D. Gillies
Affiliation: EMD-Lexigen Research Center, Billerica, MA; sgillies@emdlexigen.com
AACR TNT/IL2 PRESENTATION FROM PPHM’S 3-30-04 PR:
“The presented research describes the expression and testing of Peregrine’s Human TNT monoclonal antibody (NHS76) linked to the human cytokine Interleukin-2 (IL-2). The expressed fusion protein retained functional activity of IL-2 and had a very low toxicity profile in animal studies. TNT directed cytokines are currently under development by Merck KGaA of Darmstadt, Germany under a licensing agreement with Peregrine.
The presentation titled, “Engineering of an IL-2 immunocytokine with very low toxicity that retains potent anti-tumor activity in immune competent and immune deficient mouse tumor models", detailed a new TNT-based immunocytokine under evaluation at Merck KGaA. The immunocytokine consisted of the NHS76 targeting antibody linked to a mutant version of the cytokine IL-2 known as D2OT, which has an improved safety profile compared with native IL-2. Presented were studies in several mouse tumor models demonstrating that NHS-IL2(D20T) is extremely well tolerated and retains most of its anti-tumor activity against established metastases. The immunocytokine also retains significant anti-tumor activity although somewhat higher doses are required to achieve equivalent effects. The studies also showed that “small metastatic tumors can be targeted using an immunocytokine with specificity for a necrotic marker such as DNA.”
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PR 3-10-2004: Epstein's "TNT3/IL-12" in H.Hybridomics
No question, this TNT3/IL12 thrust has CHINA and MERCK/Germany written all over it:
Message 19902275
1. "This work was supported in part by Cancer Therapeutics, Inc. (Los Angeles, CA) and MediBiotech, Inc. (Los Angeles, CA)." ... Abstract authors: Li J, Hu P, Khawli LA, Yun A, Epstein AL.
2. "The TNT technology platform for the delivery of cytokines is currently under development by Merck KGaA of Darmstadt, Germany under a licensing agreement with Peregrine (http://www.peregrineinc.com/prelease.asp?id=140130628).
3. Recall EL in the 12-20-2001 CC: "What I do know is Medipharm is really focused on our TNT, variations of the Vasopermeation Enhancement, and TNT delivery of Cytokines".
4. From the 8-13-2003 China Approval PR: "Medipharm plans to start clinical testing in China of two new antibody based drugs in 2004. ...To date, the TNT technology platform has been used to deliver various killing agents such as radioactive isotopes, cytokines, chemokines and liposomes to solid tumors."
Reminder: Terry has uploaded THE FULL Adobe-Reader PDF of EPSTEIN's Feb2004 Hybrid Hybridomics "chTNT-3/huIL-12" article to the Peregrine Palace. Go to groups.yahoo.com and select GALLEY-PROOF.
PR 3-10-04:
"Peregrine Announces Publication of Data Related to its Tumor Necrosis Therapy Technology Platform"
peregrineinc.com
Tustin, CA – Mar. 10, 2004 - Peregrine Pharmaceuticals (NASDAQ:PPHM) announced today the publication of an article in Hybridoma and Hybridomics related to its Tumor Necrosis Therapy (TNT) technology platform. The research article describes the expression and testing of a TNT monoclonal antibody linked to the human cytokine Interleukin 12 (IL-12). The expressed fusion protein retained functional activity and induced a 44% reduction in prostate tumor growth in therapy experiments. The TNT technology platform for the delivery of cytokines is currently under development by Merck KGaA of Darmstadt, Germany under a licensing agreement with Peregrine.
Cytokines are immune system stimulators that help the human body fight infection and disease. Monoclonal antibodies are targeting agents that recognize specific structures and can be used to deliver therapeutic agents. The combination of a targeting antibody linked to a cytokine is known as an immunocytokine. In the newly published article, an immunocytokine was constructed using a TNT antibody linked to the cytokine IL-12. The TNT antibody guides IL-12 to the tumor where the cytokine can help boost the body’s ability to fight the cancer. Immunocytokines are expected to have lower side effects than conventional chemotherapy and thus represent an attractive alternative to standard tumor therapy. |
