On October 30, 2017 Aviragen Therapeutics, Inc. (NASDAQ:AVIR), a company focused on the discovery and development of direct-acting antivirals to treat infections that have limited therapeutic options, and Vaxart, Inc., a privately-held, clinical-stage company focused on developing oral recombinant vaccines based on its proprietary delivery platform that allows for administration by tablet rather than by injection, reported that the companies have entered into a definitive merger agreement (Press release, Aviragen Therapeutics, OCT 30, 2017, View Source [SID1234639795]). The merger will result in a combined company, Vaxart, Inc., focused on developing orally-delivered therapeutics and prophylactics to address a variety of viral infections.

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"We are thrilled with the prospect of combining forces with Aviragen, which will create a deep pipeline of antiviral products and allow Vaxart to accelerate development of the promising vaccine candidates that are based on our proprietary oral delivery platform," said Wouter Latour, M.D., Chief Executive Officer of Vaxart. "This transaction gives us the opportunity to build on the positive Phase 2 challenge study results we announced recently for our influenza oral tablet vaccine, as well as the excellent results we obtained in the safety and immunogenicity studies with our norovirus vaccine. Additionally, it will provide us access to Aviragen’s antiviral assets, including their BTA074 Phase 2 program for the treatment of condyloma caused by HPV, which is on track to complete enrollment this quarter and to report top-line safety and efficacy data in the second quarter of 2018."

"We believe our oral vaccine programs are significantly de-risked based on the positive clinical outcome of the BARDA-funded H1N1 influenza Phase 2 challenge study which serves as proof of concept for our technology platform as a whole," continued Latour, "and we look forward to taking our norovirus vaccine into a Phase 2 challenge study next. Norovirus is the leading cause of acute viral gastroenteritis in the United States, causing frequent outbreaks across the population, and we believe our oral tablet vaccine would be the optimal approach to address this unmet medical need."

The Vaxart technology platform has been engineered for the delivery of a wide range of oral vaccines, initially targeting norovirus, human papilloma virus (HPV), respiratory syncytial virus, and influenza, using a convenient and room temperature-stable tablet, which eliminates the need for injection. In clinical studies to date, Vaxart vaccines consistently generated broad systemic and local immune responses that could provide important advantages in preventing infection, as well as robust T cell responses that we believe are essential to obtain a therapeutic benefit in chronic viral infection and cancer.

"After a comprehensive review of strategic alternatives, we are delighted to announce this transaction with Vaxart, which will complement Aviragen’s focus on infectious diseases and position us to create both near and long-term value for our stockholders," said Joseph M. Patti, Ph.D., President and Chief Executive Officer of Aviragen Therapeutics. "Vaxart is well-funded to advance its norovirus and HPV antiviral vaccine programs, and together with BTA074, the combined companies are poised to provide meaningful value-creating data readouts."

Today, Vaxart will be announcing positive results from the company’s Phase 1b open-label, dose-ranging study assessing the safety and immunogenicity of VXA-G1.1-NN, Vaxart’s norovirus oral tablet vaccine, in 60 healthy adult volunteers. VXA-G1.1-NN met both the primary and secondary endpoints for safety and immunogenicity in the clinical trial. Based on the favorable clinical data, a Phase 2 norovirus challenge study is expected to begin in the second half of 2018. To date, Vaxart has dosed more than 300 adult volunteers with its vaccines for norovirus, respiratory syncytial virus and influenza.

About the Transaction

The exchange ratio in the merger agreement was determined by assigning $60 million in value to Aviragen for its financial and clinical assets and $90 million in value for Vaxart’s assets. On a pro forma basis, after giving effect to the number of shares of Aviragen common stock issued in the merger, Vaxart’s securityholders will own approximately 60% of the combined company and Aviragen securityholders will own approximately 40% of the combined company, subject to certain potential adjustments as described in the merger agreement. The transaction has been approved by the board of directors of both companies. The merger is expected to close in the first quarter of 2018, subject to the approval of the stockholders of each company as well as other customary conditions. Wouter Latour, M.D., will serve as Chief Executive Officer of the combined company.

Upon the closing of the transaction, the name of the combined company will become Vaxart, Inc. and shares of the combined are expected to continue trading on NASDAQ under the proposed ticker symbol "VXRT."

Stifel, Nicolaus & Company, Incorporated is acting as financial advisor to Aviragen, and Dechert LLP is serving as legal counsel to Aviragen. Cooley LLP is serving as legal counsel to Vaxart.

Aviragen will reduce its workforce by six to a total of 10 full-time employees, who will remain on board to complete the BTA074 Phase 2 clinical trial and assist with the transition of duties to the Vaxart management team.

Aviragen and Vaxart management will host a conference call this morning, Monday, October 30, 2017 at 8:30 a.m. EDT to discuss the planned merger. To participate in the conference call, please dial (877) 312-5422 (United States) or (253) 237-1122 (international) and refer to conference ID number 6295889. A replay of the conference call can be accessed under the Investors section of Aviragen’s website at www.aviragentherapeutics.com and on the Vaxart website at www.vaxart.com.

On October 30, 2017 Merrimack Pharmaceuticals, Inc. (NASDAQ: MACK) reported that the U.S. Food and Drug Administration (FDA) has granted orphan drug designation to MM-121, its investigational drug candidate, for the treatment of heregulin positive non-small cell lung cancer (Press release, Merrimack, OCT 30, 2017, View Source [SID1234521289]). MM-121 (seribantumab) is a fully human monoclonal antibody designed to block tumor survival signals and enhance the anti-tumor effect of combination therapies by targeting the cell surface receptor HER3 (ErbB3) in patients with high expression of the biomarker heregulin.

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“This is an important regulatory step forward for the clinical development of MM-121 in non-small cell lung cancer and we are pleased to have access to additional support from the FDA in this indication,” said Sergio Santillana, M.D., MSc, Chief Medical Officer. “Merrimack is dedicated to designing and developing novel precision therapeutics that shape treatment strategies for patients, and our randomized Phase 2 clinical trial of MM-121 in heregulin positive non-small cell lung cancer is well underway. We look forward to expanding the development of MM-121 to a biomarker-selected population of breast cancer patients later this year.”

The FDA’s orphan drug designation is granted to drugs and biologics intended to treat rare diseases or conditions with a prevalence of fewer than 200,000 people in the U.S. This designation includes eligibility for a seven-year period of marketing exclusivity for MM-121 upon approval, as well as other development assistance and financial incentives.

MM-121 is currently being evaluated in the SHERLOC study, a global randomized Phase 2 study that will assess progression-free survival of MM-121 in combination with docetaxel versus docetaxel alone. The study is enrolling patients with heregulin positive non-small cell adenocarcinoma of the lung who have progressed after a platinum-containing regimen and may have received anti PD-1 or anti-PD-L1 therapy. Top-line data for the SHERLOC study are expected in the second half of 2018.

In addition, Merrimack will be evaluating MM-121 in the SHERBOC trial, a global randomized Phase 2, double-blind, placebo-controlled clinical study of MM-121 added to standard of care in patients with heregulin positive, hormone receptor positive, HER2 negative metastatic breast cancer. The first patient is expected to be dosed in the SHERBOC study by the end of 2017.

About MM-121

MM-121, also known as seribantumab, is Merrimack’s wholly owned, fully human anti-HER3 (ErbB3) monoclonal antibody that targets phenotypically distinct heregulin positive cancer cells within solid tumors. Heregulin positive cancer cells are characterized by their ability to escape the effects of targeted, cytotoxic and anti-endocrine therapies and potentially contribute to rapid clinical progression in patients whose tumor cells test positive for heregulin as detected by RNA-ISH. When used in the combination setting, seribantumab is designed to block the heregulin/HER3 signaling axis to make tumor cells more sensitive to the effects of the combination therapy.

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On October 29, 2017 Esanex, Inc., a clinical stage company developing Heat Shock Protein inhibitors for the treatment of cancer, reported that it is presenting preclinical data from its Heat Shock Protein 90 (Hsp90) inhibitor SNX-5422 program, showing promising anti-tumor effects both alone and in combination with checkpoint inhibitors, at the AACR (Free AACR Whitepaper)-NCI-EORTC AACR-NCI-EORTC (Free AACR-NCI-EORTC Whitepaper) International Conference on Molecular Targets and Cancer Therapeutics (EORTC-NCI-AACR) (Free ASGCT Whitepaper) (Free EORTC-NCI-AACR Whitepaper) (Press release, Esanex, OCT 29, 2017, View Source [SID1234521339]).

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"Results from these two studies reaffirm our belief in the potential of SNX-5422 both as a monotherapy and in combination with immuno-oncology drugs," said Everardus (Eric) Orlemans, Ph.D, Chief Scientific Officer and Senior Vice President, Development, Esanex. "We are conducting further research to explore the potential of SNX-5422 in other indications as well as through our ongoing Phase 1b trial in chronic lymphocytic leukemia. The results from the combination research support further development of SNX-5422 in combination with checkpoint inhibitors for the potential treatment of a number of cancer types."

The two posters will be presented October 29th at 12:30 – 4:00 pm EST, in Hall E, Pennsylvania Convention Center.

Poster B139: "Promising antitumor effects of SNX-5422 in combination with checkpoint inhibitors in an MC38 murine model", presented at the session PO.B20 – Therapeutic Agents: Other Topics.
SNX-5422 is an orally active prodrug of SNX-2112, a potent, highly selective inhibitor of Hsp90. The results described in the poster show that SNX-5422 at either 25 mg/kg or 40 mg/kg, in combination with the immune checkpoint inhibitors anti-PD1, PD-L1 or CTLA4, demonstrated significant antitumor activity in the MC38 murine colon cancer model.

Poster B026: "SNX-2112 interferes with mitochondrial metabolism in TP53 mutant tumors", presented at the session PO.B05 – Metabolism.
In vitro work with SNX-2112, the active derivative of SNX-5422, demonstrated significant antitumor activity in TP53 null tumors and in rearranged MYC hematologic and selected solid tumors (e.g., hepatocellular carcinoma, mesothelioma). This activity appears to be, in part, the result of interference with cancer related metabolic pathways.

About SNX-5422
SNX-5422 is a chemically unique, orally active Hsp90 inhibitor that has provided durable clinical responses in open label trials in non-small cell lung cancer (NSCLC) and neuroendocrine tumors (NET). The potential of SNX-5422 in hematologic cancers is currently being explored in a chronic lymphocytic leukemia (CLL) open label clinical trial (clinicaltrials.gov ID#NCT02973399). With approximately 200 patients treated to date, SNX-5422 has a well-established safety profile that supports studying it in combination with existing approved drugs in a variety of clinical settings.

On October 29, 2017 Rgenix, Inc., a clinical stage biopharmaceutical company developing first-in-class small molecule and antibody can, cer therapeutics, reported preliminary data from an ongoing Phase 1a/b clinical trial with its lead oral investigational agent, RGX-104 (Press release, Rgenix, OCT 29, 2017, View Source [SID1234521283]). These data demonstrate immune-stimulatory activity in solid tumor patients with highly-refractory malignancies, including patients who have failed prior checkpoint inhibitors. Also presented were pre-clinical data establishing the immune-modulatory and anti-tumor effects of RGX-104. The company presented the data at the AACR (Free AACR Whitepaper)-NCI-EORTC AACR-NCI-EORTC (Free AACR-NCI-EORTC Whitepaper) International Conference on Molecular Targets and Cancer Therapeutics (EORTC-NCI-AACR) (Free ASGCT Whitepaper) (Free EORTC-NCI-AACR Whitepaper) in Philadelphia.

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RGX-104 is a liver X receptor (LXR) agonist that upregulates the expression of the target gene, Apolipoprotein E (ApoE), triggering several downstream effects via ApoE receptors. In pre-clinical data presented today, treatment with RGX-104 in mouse models resulted in dual effects on myeloid-derived suppressor cells (MDSCs) and dendritic cells (DCs), both innate immune cells that play a central role in regulating anti-tumor immunity and response to checkpoint inhibitors. Innate immune activation with RGX-104, coupled with a reduction in tumor blood vessels, resulted in anti-tumor activity as a monotherapy as well as synergy with checkpoint inhibitors (CPI) in several drug-resistant mouse models. These data provide rationale for Rgenix’s ongoing Phase 1a/b trial of RGX-104 in advanced cancer patients and support evaluation of RGX-104 as both a monotherapy as well as in combination with CPIs.

As part of the ongoing Phase 1a/b clinical trial, 15 patients with a variety of solid tumors have been treated with escalating doses of RGX-104 monotherapy. Patients treated with RGX-104 had a median of six prior therapies with a range of 1-12, highlighting a population of patients with profoundly resistant disease.

Activation of the LXR-ApoE pathway with oral administration of RGX-104 was associated with immune-stimulatory activity in 9 of 10 evaluable patients. This was demonstrated by an increase (up to 11-fold) in activated circulating PD-1+CD8+ T cells during treatment. T cell activation was observed in patients who experienced modulation of the innate immune system during treatment. The effect of RGX-104 on the innate immune system consisted of both MDSC depletion (up to 95% decrease) as well as DC activation as indicated by induction of PD-L1 expression (up to 100% increase). In most cases these effects were observed within two weeks of treatment initiation and generally preceded the onset of T cell activation.

Safety data demonstrate good tolerability with on-target safety findings in the first three dosing cohorts. One patient experienced a DLT of grade 4 reversible neutropenia – a known potential effect of LXR agonism – that reversed within one week, allowing the patient to subsequently tolerate a 50% dose reduction. No MTD has been reached to date. Stable disease has been observed in 4 of 12 evaluable patients, including three who have failed prior checkpoint inhibitor therapy, for periods of at least 8 weeks.

“We are very pleased to see robust evidence of immune stimulation in such highly-pretreated patients,” said Roger Waltzman, MD, MBA, and Chief Medical Officer of Rgenix. “CPI therapy is now commonplace but only a minority of patients derive clinical benefit. We hope the effects of RGX-104 on modulating barriers to innate and adaptive immune function will enable a larger number of patients to benefit from this therapy. These preliminary results also highlight the potential for development of RGX-104 as a monotherapy.”

Rgenix plans to enroll subsequent dose-escalation cohorts of the RGX-104 monotherapy trial in Q4 2017. Additionally, Rgenix is planning to initiate the Phase 1b expansion component of the study, comprised of disease directed cohorts receiving RGX-104 monotherapy as well as cohorts receiving RGX-104 combined with a CPI, projected to begin in 1H 2018.

“These preliminary data establish RGX-104 as a potential first-in-class oral immunotherapy agent with broad immune-stimulatory activity and a unique dual mechanism targeting innate immunity,” said Masoud Tavazoie, MD, PhD, and Chief Executive Officer of Rgenix. “These results also further validate our discovery platform at Rgenix, as well as our pipeline of other drug candidates slated to begin entering clinical-stage development in 2018.”

The LXR-ApoE pathway was discovered as a cancer target using a microRNA (miRNA) based target discovery approach originally developed at The Rockefeller University and now exclusively licensed to Rgenix.