“We are pleased to present data at this year’s AACR that highlight three platform technologies upon which multiple molecules are being developed at
AACR II Presentations
MGC018, a duocarmycin-based antibody-drug conjugate targeting B7-H3, exhibits immunomodulatory activity and enhanced antitumor activity in combination with checkpoint inhibitors
Poster Session: PO.ET07.01 - Cell Surface Antigens and Receptors as Drug Targets
MGC018 is an investigational antibody-drug conjugate targeting B7-H3 that has shown preliminary anti-tumor activity in an ongoing Phase 1 dose escalation study in patients with advanced solid tumors. The poster presented at AACR describes preclinical data suggesting that MGC018 can promote immune surveillance or stimulate immune responses to dying cancer cells that led to immunological memory, and when combined with checkpoint blockade may enhance anti-tumor activity.
These studies used a mouse model system designed to evaluate anti-tumor activity in an intact and functioning immune system. In this in vivo model, MGC018 demonstrated targeted activity against tumors expressing human B7-H3. Mechanistically, in vitro data suggested that MGC018 induced immunogenic cell death of target cells with the translocation of calreticulin to the cell surface during apoptosis. In addition, treatment with MGC018 in this model system led to an increased infiltration of T cells into the tumor microenvironment. Depleting these T cells attenuated the anti-tumor activity by MGC018, demonstrating their role in mediating response. Furthermore, MGC018 combined with an anti-PD-1 antibody enhanced anti-tumor activity observed in this study. Finally, mice that had achieved a complete response to initial treatment with MGC018 with or without checkpoint blockade survived longer when re-challenged with tumor without subsequent treatment compared to mice that had not received treatment with MGC018, suggesting immunological memory.
Investigational CD25 x CTLA-4 bispecific DART® molecule for depletion of tumor infiltrating Tregs via an enhanced Fc-dependent effector mechanism
Poster Session: PO.IM02.23 - Therapeutic Antibodies 1
The poster presented at AACR described a preclinical bispecific CD25 x CTLA-4 DART molecule containing an Fc region engineered to enhance clearance of target cells by antibody-dependent cellular cytotoxicity. This molecule was designed to deplete tumor-associated regulatory T cells co-expressing CD25 and CTLA-4 to reduce immune suppression mediated by these cells but preserve effector T cell function. CD25 is the alpha subunit of IL-2 receptor and CTLA-4 is a molecule involved in regulatory T cell function.
In vitro studies showed that the Fc-engineered bispecific CD25 x CTLA-4 DART molecule depleted regulatory T cells, with minimal effect on effector T cells. This depletion of regulatory T cells was shown to occur through an Fc-dependent mechanism, as a control CD25 x CTLA-4 DART molecule with an inactivated Fc domain had no effect in this assay. In addition, the bispecific CD25 x CTLA-4 DART molecule preserved cytotoxic T cell effector function in vitro compared to a combination of Fc-engineered monoclonal antibodies independently targeting CD25 and CTLA-4.
Immune escape after bone marrow transplantation: Hiding in plain sight
Educational Session: ED52 - Immunotherapy, Immune Evasion in Myeloid Malignancies, and Therapeutic Implications
Location: AACR Virtual Annual Meeting II at www.aacr.org
The posters will be available on the Events & Presentations page on MacroGenics’ website at http://ir.macrogenics.com/events.cfm.
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Any statements in this press release about future expectations, plans and prospects for the Company, including statements about the Company's strategy, future operations, clinical development of the Company's therapeutic candidates, milestone or opt-in payments from the Company's collaborators, the Company's anticipated milestones and future expectations and plans and prospects for the Company and other statements containing the words "subject to", "believe", "anticipate", "plan", "expect", "intend", "estimate", "project", "may", "will", "should", "would", "could", "can", the negatives thereof, variations thereon and similar expressions, or by discussions of strategy constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including: the uncertainties inherent in the initiation and enrollment of future clinical trials, expectations of expanding ongoing clinical trials, availability and timing of data from ongoing clinical trials, expectations for the timing and steps required in the regulatory review process, expectations for regulatory approvals, the impact of competitive products, our ability to enter into agreements with strategic partners and other matters that could affect the availability or commercial potential of the Company's product candidates, business or economic disruptions due to catastrophes or other events, including natural disasters or public health crises such as the novel coronavirus (referred to as COVID-19), and other risks described in the Company's filings with the
Anna Krassowska, Ph.D., Vice President, Investor Relations & Corporate Communications Jim Karrels, Senior Vice President, CFO 1-301-251-5172, firstname.lastname@example.org
Source: MacroGenics, Inc.