Five Prime to Present Preclinical Data at 2016 SITC Annual Meeting Demonstrating Potent Anti-Tumor Activity with Novel Tetravalent Anti-GITR Antibody

On November 11, 2016 Five Prime Therapeutics, Inc. (Nasdaq:FPRX), a clinical-stage biotechnology company focused on discovering and developing innovative immuno-oncology protein therapeutics, reported that a poster featuring preclinical data related to its tetravalent anti-GITR agonist antibody, FPA154, was presented today at the Society for Immunotherapy of Cancer (SITC) (Free SITC Whitepaper) Annual Meeting in National Harbor, Maryland (Press release, Five Prime Therapeutics, NOV 11, 2016, View Source [SID1234516495]). Poster #175 titled, "Novel tetravalent anti-GITR antibody is a potent anti-tumor agent in vivo," is available at View Source

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"With our lead anti-GITR candidate, FPA154, now in pre-IND enabling studies, we are pleased to highlight our first preclinical data supporting the development and differentiation of this novel, tetravalent antibody," said Luis Borges, Ph.D., Senior Vice President of Research, at Five Prime. "In vitro data demonstrates that our tetravalent antibody has agonistic activity in the absence of Fc-mediated crosslinking. In vivo, the antibody has potent anti-tumor activity in various murine tumor models and it confers long-term anti-tumor immunity. It alters the ratio of Tregs to effector T cells, creating a favorable environment for an effective anti-tumor immune response. These findings suggest the potential for FPA154 to activate T cell immunity against various tumors and we are working to move this program rapidly toward clinical development."

FPA154 has been designed using single-domain antibodies in a tetravalent format, inducing effector T cell stimulation in vitro that is superior to a conventional bivalent antibody format and conferring agonistic activity even in the absence of Fc-mediated crosslinking. The poster features preclinical data provided by a mouse-reactive surrogate molecule that demonstrate potent inhibition of tumor growth in mouse tumor models:

Potent anti-tumor activity following a single dose: A single dose of tetravalent anti-GITR significantly inhibited tumor growth in multiple models including CT26 and MC38. Treatment was capable of inducing complete tumor rejection, and activity was observed at doses as low as 0.08 mg/kg in both models.

Fc-independent activity: Tetravalent anti-GITR antibody retained partial tumor growth inhibition activity even in the absence of Fc-mediated crosslinking or effector function, whereas a conventional bivalent antibody (DTA-1) required Fc function.
Pharmacodynamic responses: Tetravalent anti-GITR antibody treatment reduced the number of T cells in the peripheral blood 3 days post-treatment. In the tumor, Treg and conventional CD4 T cells decreased, but CD8 T cell numbers were maintained. This resulted in a ratio of CD4 and CD8 effector T cells to Treg that created a favorable environment for an effective anti-tumor immune response.

Induction of long-term immunity: Mice that eliminated CT26 tumors in response to tetravalent anti-GITR were resistant to tumor regrowth upon re-challenge with the same tumor, but not to an antigenically-unrelated tumor.

Atreca Presents Promising Findings from Lead Antibody Program at Society for Immunotherapy of Cancer (SITC) Annual Meeting

On November 11, 2016 Atreca, Inc., a biotechnology company focused on developing novel therapeutics based on a deep understanding of the human immune response, reported positive preclinical findings generated using the Company’s Immune Repertoire Capture (IRC) technology, presented at the SITC (Free SITC Whitepaper) 2016 Annual Meeting, which is taking place in National Harbor, Maryland, November 9-13, 2016 (Press release, Atreca, NOV 11, 2016, View Source [SID1234522962]). In a poster titled, "Immune Profiling of an Elite Responder Following Checkpoint Inhibitor Therapy Reveals Functional Anti Tumor Antibodies Within Expanded IgG Lineages," a research team including scientists at Atreca and collaborators at a leading institution reported key research findings, including:

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Atreca’s IRC technology generated diverse antibodies from the active immune response of an individual with Stage 4 melanoma who had experienced long-term non-progression of disease following cancer regimens including anti-CTLA4 immunotherapy. These antibodies were sequenced from the patient’s blood plasmablasts, activated B cells that play a critical role in immune responses.
In in vitro assays, antibodies were shown to selectively bind tumor tissue but not normal tissue and to bind tumor types beyond the cancer type of the original patient.
Select antibodies demonstrated in vitro tumor killing through antibody-dependent cellular cytotoxicity (ADCC).
"Atreca is pioneering next-generation approaches to cancer immunotherapy based on our ability to elucidate the repertoire of cancer patient antibodies and T cell receptors (TCRs) contributing to positive outcomes," stated Daniel Emerling, Ph.D., Atreca’s Senior Vice President, Research. "In our presentation at SITC (Free SITC Whitepaper), we reported sequencing of over 2500 plasmablasts and identification of clonal antibody families from one exceptional cancer responder. By generating natively paired antibody heavy and light chain sequences, we were able to confirm the ability of a patient’s antibodies to target tumor cells and destroy them, including tumor types unrelated to that of the patient."

"Atreca is advancing a pipeline of therapeutic candidates that can drive and focus the activity of immune responses in cancer immunotherapy, particularly those unleashed by checkpoint inhibitors and immune activators," said Tito A. Serafini, Ph.D., Atreca’s President, Chief Executive Officer, and Co-Founder. "We are thrilled to present data highlighting the power and productivity of our platform at one of the leading cancer immunotherapy conferences. Our lead program is rapidly advancing in preclinical in vivo studies, and we look forward to further progress of our additional programs across multiple indications."

For more information on Atreca’s product portfolio, please visit View Source

Adaptimmune Presents Preclinical Data from a New, Wholly-owned SPEAR™ T-cell and a Second Generation SPEAR T-cell at the 31st Annual Meeting of the Society for Immunotherapy for Cancer (SITC)

On November 11, 2016 Adaptimmune Therapeutics plc (Nasdaq:ADAP), a leader in T-cell therapy to treat cancer, reported the presentation of data at the 2016 Society for Immunotherapy for Cancer (SITC) (Free SITC Whitepaper) annual meeting (Press release, Adaptimmune, NOV 11, 2016, View Source;p=RssLanding&cat=news&id=2221778 [SID1234516497]). The posters summarize: (1) preclinical data from Adaptimmune’s wholly-owned MAGE-A4 SPEAR (Specific Peptide Enhanced Affinity Receptor) T‑cells; (2) preclinical data from the Company’s second generation SPEAR T-cell, which is engineered to overcome immunosuppression in the tumor microenvironment by blocking the effects of transforming growth factor Beta (TGF-Beta); and (3) a single-patient case study from the Company’s ongoing synovial sarcoma study. The 2016 SITC (Free SITC Whitepaper) annual meeting is being held at the Gaylord National Hotel & Convention Center in National Harbor, Maryland on November 9 through 13, 2016.

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"We are pleased to present the preclinical data that underpins the decision to progress our next SPEAR T‑cell candidate, MAGE-A4, into clinical trials and we plan to file an IND in early 2017," said Gwendolyn Binder-Scholl, PhD Adaptimmune’s Chief Technology Officer. "MAGE–A4 is an attractive target which is broadly expressed in multiple solid tumors. Our MAGE-A4 SPEAR T-cell candidate has shown promising activity without any major safety concerns identified by our extensive preclinical testing. In addition, we are presenting initial data from a second generation NY-ESO SPEAR T-cell to overcome TGF‑Beta immunosuppression in the tumor microenvironment, as well as translational results from a case study of a patient with synovial sarcoma treated with NY-ESO SPEAR T‑cells. We believe that this type of data underscores our leadership in the field, and helps us to improve the function of SPEAR T-cells and inform future clinical study design."

Preclinical Testing of Wholly-owned MAGE-A4 SPEAR T-cells
In a poster presentation entitled, "Preclinical evaluation of an optimal-affinity MAGE-A4 T-cell receptor for adoptive T-cell therapy," Daniel Williams, Ph.D. of Adaptimmune, presented data examining MAGE-A4 expression in tumor and non-tumor tissues, and generation of an optimal affinity-enhanced MAGE-A4 SPEAR T‑cell.

MAGE-A4 is a cancer‑testis antigen, one of a number of genes with expression in adult tissues restricted to the testes, but also known to be expressed in several tumor types;
Target validation data indicates that MAGE-A4 is a very attractive target due to widespread and frequent expression in multiple tumor types including non‑small cell lung cancer, bladder, melanoma, head and neck, ovarian, esophageal, and gastric cancers with no detectable expression in non-tumor, non-germline tissues;
No major safety concerns were identified for MAGE-A4 SPEAR T-cells using Adaptimmune’s extensive in vitro preclinical testing platform;
MAGE-A4 SPEAR T-cells displayed strong cytotoxicity towards MAGE-A4+ melanoma and NSCLC cell lines, and;
These data will support filing of an IND, with submission planned for early 2017.
Second Generation SPEAR T-cell Engineered to Overcome TGF-Beta Tumor-mediated Immunosuppression
In a poster presentation entitled, "Engineering 2nd generation SPEAR T-cells to overcome TGF-Beta-mediated immunosuppression for adoptive cell therapy," Andrew Gerry, Ph.D. of Adaptimmune presented preclinical data regarding the development of this second generation SPEAR T-cell.

NY-ESO SPEAR T-cells have shown promising activity in clinical trials for both solid and liquid tumors. However, the depth and durability of response may potentially be affected by inhibitory factors in the tumor microenvironment;
One such factor is an inhibitory cytokine known as TGF-Beta that inhibits many T‑cell functions including proliferation, cytotoxicity, and cytokine production. Truncation of the intracellular signaling domain of the TGF-Beta receptor produces a dominant negative form of this receptor (dnTGFBetaRII), and data from the literature indicate that expression of this dominant negative receptor negates the inhibitory effects of TGF-Beta;
Adaptimmune engineered a second generation NY-ESO SPEAR T-cell co-expressing dnTGFBetaRII to produce resistance to TGF-Beta immunosuppression, and;
Data indicate that these second generation NY-ESO SPEAR T-cells co-expressing dnTGFBetaRII are resistant to inhibition by TGF-Beta in vitro.
Case Study Demonstrating Long-term SPEAR T-cell Persistence and Maintenance of Tumoricidal Activity
In a poster presentation entitled, "Case Report: Specific Peptide Enhanced Affinity Receptor T-Cells (SPEAR T-cells) demonstrate long-term persistence and both in vivo and ex vivo tumoricidal activity," Samik Basu M.D. and Gareth Betts Ph.D., both of Adaptimmune, presented translational data from a single patient who was treated in October 2013 in Cohort 1 of the ongoing study of NY-ESO SPEAR T-cell in synovial sarcoma. This patient was included in analyses that have been previously presented.

Data indicate that NY-ESO SPEAR T-cells have long-term persistence as they were readily detectable in the patient’s peripheral blood at 28 months post-infusion;
These cells exhibited markers of long‑term, self-renewing memory T-cells with minimal expression of phenotypic markers of exhaustion;
NY-ESO SPEAR T-cells retained tumoricidal activity when they were evaluated ex vivo against tumor targets exhibiting substantial killing of NY-ESO-1+ cells without additional re-stimulation, and;
Mechanisms underlying tumor progression remain under investigation and broadly appear to be related to T-cell exclusion by tumor, supporting consideration of rational combination study designs.

Adaptimmune Announces Update on Clinical Data from NY-ESO SPEAR™ T-cell Synovial Sarcoma Study at the 2016 Annual Meeting of the Connective Tissue Oncology Society (CTOS)

On November 11, 2016 Adaptimmune Therapeutics plc (Nasdaq:ADAP), a leader in T-cell therapy to treat cancer, reported an oral presentation with updated data on its study of NY‑ESO SPEAR (Specific Peptide Enhanced Affinity Receptor) T‑cells in the ongoing synovial sarcoma trial at the 2016 Connective Tissue Oncology Society (CTOS) annual meeting presented by Dr. Sandra P. D’Angelo of the Memorial Sloan Kettering Cancer Center (Press release, Adaptimmune, NOV 11, 2016, View Source;p=RssLanding&cat=news&id=2221814 [SID1234516498]). This presentation included an update to Cohort 1 median survival data. The meeting is being held at the Corinthia Hotel in Lisbon, Portugal from November 9 through 12, 2016.

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In an oral presentation entitled, "Open Label Non-Randomized Multi-Cohort Pilot Study of Genetically Engineered NY-ESO-1 Specific NY-ESO SPEAR T-cells in HLA-A*02+ Patients with Synovial Sarcoma," Dr. Sandra P. D’Angelo of the Memorial Sloan Kettering Cancer Center described that median survival for Cohort 1 is now calculated to be ~18 months (80 weeks), compared to ~13 months (56 weeks) as previously reported. The updated median survival calculation is based on analyses of additional patient follow-up data (cutoff of September 30, 2016). Other updates indicate that there continue to be additional partial responses among low NY-ESO expressors in Cohort 2, which is ongoing.

Idera Pharmaceuticals Reports Translational Data Supporting the Mechanism of Action of Intratumoral IMO-2125 from Ongoing Phase 1 Dose Escalation in Clinical Trial in Combination with Ipilimumab in Metastatic Melanoma Patients Refractory to Anti-PD-1 Treatment

On November 11, 2016 Idera Pharmaceuticals, Inc. (NASDAQ:IDRA), a clinical-stage biopharmaceutical company developing toll-like receptor and RNA therapeutics for patients with cancer and rare diseases, is reporting translational data supporting the mechanism of action of intratumoral IMO-2125, a Toll-like receptor (TLR) 9 agonist from the ongoing Phase 1 dose escalating clinical trial (Press release, Idera Pharmaceuticals, NOV 11, 2016, View Source;p=RssLanding&cat=news&id=2221857 [SID1234516527]). In this trial, IMO-2125 is being evaluated in combination with ipilimumab for treatment of patients with metastatic melanoma with disease that is refractory to anti-PD-1 inhibitors, and have minimal options and low expectation of clinical response with ipilimumab treatment alone. Taken together, the previously reported early clinical responses and the supporting mechanism of action translational data being presented today, indicate that intratumoral IMO-2125 is a potent agent for the stimulation of the tumor microenvironment.

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In the oral presentation at the 2016 Society for Immunotherapy of Cancer (SITC) (Free SITC Whitepaper) Annual Meeting (SITC) (Free SITC Whitepaper), entitled "Reactivating the anti-tumor immune response by targeting innate and adaptive immunity in a phase I/II study of intratumoral IMO-2125 in combination with systemic ipilimumab in patients with anti-PD-1 refractory metastatic melanoma," Cara Haymaker, Ph.D., from the University of Texas, MD Anderson Cancer Center, presented an overview of the modulation of the tumor microenvironment through the unique mechanism of action of intratumoral IMO-2125 and provided an update on the initial findings of the translational data through the first cohorts of the trial. Immunological analysis of the biopsy taken from the lesion injected with IMO-2125 showed rapid dendritic cell maturation which is a critical first step in the induction of the immune cascade within the tumor microenvironment. During the treatment period, T-cell expansion and activation and importantly, immune infiltration was observed in the biopsied distant lesions of the responding patients, demonstrating the abscopal effect.

From a clinical perspective, through all dosing cohorts tested to date, no dose-limiting toxicity has been seen. Preliminary clinical activity is also encouraging in this population with disease that is refractory to PD-1 inhibitors as 3 responses (including one CR) have already been recorded. The trial continues to dose escalate and enrollment into the planned anti-PD-1 inhibitor combination arm has also commenced.

"We hypothesized that the intratumoral injection of IMO-2125 into a single tumor lesion would stimulate dendritic cells to produce interferon and the downstream immune cascade in the tumor microenvironment, resulting in the recruitment and activation of tumor-killing T-cells in both the injected and non-injected tumors," said Joanna Horobin, M.B., Ch.B., Idera’s Chief Medical Officer. "When combined with a systemic checkpoint inhibitor, this change in the tumor microenvironment was expected to affect tumor responses in both injected and distant tumors. Today Dr. Haymaker presented analyses of serial biopsies from the tumors of patients with anti-PD-1 refractory melanoma in our ongoing phase 1 dose escalation trial of intratumoral IMO-2125 which clearly demonstrated these beneficial changes in the tumor microenvironment, essentially turning "cold" tumors "hot" in responding patients. We are thrilled to see what we believe to be, the clear translation of our hypothesis in patients. Moreover, in three patients the investigator has reported substantial tumor shrinkage with 2 partial and one complete response."

A copy of the slides from today’s presentation as well as a copy of a related poster presentation are currently available on Idera’s corporate website at View Source

These early results are from the phase 1 portion of study IMO-2125-204 (NCT02644967) in which cohorts of patients with metastatic melanoma unresponsive to PD-1 inhibitor therapy are being administered escalating doses of IMO-2125 ranging from 4 mg/kg through 32 mg/kg. IMO-2125 is injected intra-tumorally into a designated tumor lesion together with a standard dosing regimen of ipilimumab. The trial has recently been amended to also study the combination of IMO-2125 and pembrolizumab given intravenously. Following determination of the recommended phase 2 doses (RP2D) additional patients will be treated in an expansion phase 2 portion of the study. The primary objective of the phase 1 portion of the trial is to characterize the safety and determine a RP2D of IMO-2125 when administered intra-tumorally in combination with ipilimumab or pembrolizumab. The primary objective of the phase 2 portion is to assess the clinical activity of IMO-2125 in each combination at the respective RP2Ds. Assessment will be based on the immune-related response criteria (irRC) and additionally the traditional RECIST criteria. Serial biopsies are being taken of selected injected and non-injected tumor lesions to assess immune changes and correlate with clinical response assessments. The trial will enroll approximately 60 patients. The study is being conducted at MD Anderson and is being led by Adi Diab, MD, Assistant Professor, Department of Melanoma Medical Oncology, Division of Cancer Medicine, MD Anderson as part of a strategic research alliance announced by Idera and MD Anderson in 2015.

Additionally at SITC (Free SITC Whitepaper), on November 9th, Idera’s Oncology Lead, Mark Cornfeld, M.D., M.P.H., presented an overview of IMO-2125’s unique mechanism of action in an oral presentation, entitled "IMO-2125, An Investigational Intratumoral Toll-Like Receptor 9 Agonist, Modulates the Tumor Microenvironment to Enhance Anti-Tumor Immunity" during a session focused on New Clinical Agents in Development. A copy of the slides from this presentation is currently available on Idera’s corporate website at View Source

About Toll-like Receptors and Idera’s Immuno-Oncology Research Program

Toll-like receptors (TLRs) play a central role in the innate immune system, the body’s first line of defense against invading pathogens, as well as damaged or dysfunctional cells including cancer cells. The innate immune system is also involved in activating the adaptive immune system, which marshals highly specific immune responses to target pathogens or tissue. Cancer cells may exploit regulatory checkpoint pathways to avoid being recognized by the immune system, thereby shielding the tumor from immune attack. Checkpoint inhibitors such as agents targeting CTLA4 or programmed cell death protein 1 (PD1) are designed to enable the immune system to recognize tumor cells. In this setting, intra-tumoral TLR9 agonist administration may increase the tumor-infiltrating lymphocytes (TILs), and thereby potentiate anti-cancer activity of checkpoint inhibitors in the injected tumor as well as systemically.

Idera’s TLR9 agonists, IMO-2125 and IMO-2055, have been created using the company’s proprietary chemistry-based discovery platform. IMO-2125 has been shown in various scientific presentations and publications to activate dendritic cells and induce interferon. Idera selected IMO-2125 to advance into clinical development in combination with checkpoint inhibitors based on this immunological profile. In previously completed clinical trials, subcutaneous administration of IMO-2125 was generally well tolerated in about 80 patients with hepatitis C. Idera has conducted further preclinical research evaluating the potential of IMO-2125 to enhance the anti-tumor activity of other checkpoint inhibitors in cancer immunotherapy with data being presented at several medical conferences during the past twelve months. The posters from these presentations can be found at View Source

About Metastatic Melanoma
Melanoma is a type of skin cancer that begins in a type of skin cell called melanocytes. As is the case in many forms of cancer, melanoma becomes more difficult to treat once the disease has spread beyond the skin to other parts of the body such as by through the lymphatic system (metastatic disease). Melanoma accounts for only one percent of skin cancer cases, but causes a large majority of skin cancer deaths. The American Cancer Society estimates that in 2016, there will be 76,380 new cases of melanoma in the U.S., and about 10,130 will die of this disease.