APX-2039

The entrance to a Pfizer office in Cambridge, Massachusetts Pfizer joined an equity investment in clinical-stage Amplyx Pharmaceuticals last year to support the biotech’s development of a new antifungal for drug-resistant pathogens. On Wednesday, the pharmaceutical giant announced it has acquired the company outright. No financial terms were disclosed for the deal. The acquisition of San Diego-based Amplyx comes as the biotech evaluates its lead compound, fosmanogepix, in Phase 2 tests as a potential treatment for life-threatening fungal infections caused by a range of fungal pathogens including Aspergillus, Candida, Fusarium, and Scedosporium. Fosmanogepix is small molecule is designed to block Gwt1, a fungal enzyme that is important for anchoring a key protein needed to maintain the integrity of the fungal cell wall. The company says its drug does not block the human protein closest to Gwt1, and therefore can target fungal pathogens without harming healthy human cells. Pfizer said this new approach could add a new therapeutic class to the three classes of antifungals currently available. Amplyx is evaluating both intravenous and oral formulations of its antifungal candidate. In Phase 1 tests, both formulations were well tolerated and demonstrated safety. The company added that both formulations have a low propensity for interacting with other drugs. The company says developing both IV and oral formulations may allow for patients to continue their care, transitioning from IV dosing in the hospital to a pill version after discharge. Pfizer’s top antifungal product voriconazole, which is marketed as Vfend, accounted for $270 million in 2020 sales, a nearly 22% decline from the prior year. That drug has lost patent protection and generic versions are eating away at its market share. Vfend is part of Pfizer’s lineup of hospital-based products, which generated $7.9 billion in revenue last year. The equity financing that Amplyx announced last year was an extension of a $67 million Series C round from 2017. Last May, the company said that Pfizer and Adage Capital Management joined the financing, extending it to more than $90 million. With the acquisition, Pfizer also gains other programs in the Amplyx pipeline. MAU868, an antiviral, is in early clinical development. The antifungal candidate APX2039 is preclinical.

Erik McGregor/LightRocket via Getty Images Pfizer is expanding its presence in infectious diseases with the acquisition of San Diego-based Amplyx Pharmaceuticals and its lead antifungal compound Fosmanogepix (APX001). Terms of procurement were not disclosed. Fosmanogepix is an investigational asset in development as a front-line treatment against invasive fungal infections, including Candida auris, which is highly resistant to antimicrobials and is considered one of the highest threats by the U.S. Centers for Disease Control and Prevention. The fungal infection immediately spreads from the contaminated patient and can infect surface areas and more. In 2019, in a New York hospital, a patient's room had to be renovated entirely following that patient's death. In addition to Candida auris, which is part of a family of Candida fungi, fosmanogepix is being assessed against other fungal infections, including Aspergillus spp, Fusarium spp, and Scedosporium sp. In July, Amplyx announced Phase II data that showed its fosmanogepix demonstrated a treatment success rate of 80% against candida. While the deadly Candida auris only hits about 1,000 patients in the United States annually, there are more cases worldwide. Additionally, the broader candida bucket is about 100,000 patients per year with a 30% to 40% mortality rate, Amplyx Chief Executive Officer Ciara Kennedy told BioSpace last year. Amplyx has assessed fosmanogepix as both an oral and intravenous treatment for invasive fungal infections in multiple Phase II programs. Fosmanogepix has demonstrated broad-spectrum activity in-vitro and has shown wide distribution to various tissues, including the brain, lung, kidney and eye. Each year, more than 1.5 million cases of invasive fungal infections occur globally. Some of these infections, such as Candida auris, have a high mortality rate, up to 80%. There has been no novel therapeutic class of antifungal therapies approved by the U.S. Food and Drug Administration in almost 20 years. And, there are currently only three classes of antifungal medications available, Pfizer said, which means antifungal resistance can severely limit treatment options. Angela Lukin, Global President of Pfizer's Hospital business unit, said COVID-19 has been a "stark reminder" of the devastating impact of infectious diseases and highlights the need for new anti-infective therapies, both bacterial and fungal infections. "We are deeply committed to helping patients suffering from infectious diseases, continuously seeking opportunities to build our portfolio of anti-infective therapies. We've already invested in assets that, if approved, could help address drug-resistant bacterial infections and critical viral infections; with this acquisition, we look forward to progressing the development of a novel antifungal as well," Lukin said in a statement. In addition to fosmanogepix, Pfizer also gains Amplyx's early-stage pipeline, including potential antiviral (MAU868) and antifungal (APX2039) therapies. MAU868, licensed from Novartis, is a potent neutralizing monoclonal antibody with activity against the BK virus. APX2039 is a novel Gwt1 Inhibitor in preclinical development as a potential treatment for cryptococcus, an invasive fungus that causes cryptococcosis. The entire financial terms of the acquisition were not disclosed. However, Pfizer had already been an investor in Amplyx. In 2019, the company backed an oversubscribed $90 million Series C financing round at Amplyx.