Molecular Partners Confirms Ultra-Potent Inhibition of SARS-CoV-2 Live Virus by Anti-COVID-19 DARPin® Candidates
Zurich-Schlieren, Switzerland, May 7, 2020. Molecular Partners AG (SIX: MOLN), a clinical-stage
biotech company that is developing a new class of custom-built protein therapeutics known as
DARPin® therapeutics, today announced completion of in vitro potency assessments of its DARPin® candidates targeting live, replicating coronavirus SARS-CoV-2. These candidates show extremely robust antiviral activity, with several candidates demonstrating complete neutralization with low picomolar potency. This suggests only very small amounts of these candidates may be required for therapeutic effect, which complements the company’s ability to rapidly manufacture DARPin® candidates with high yields.
“We are greatly encouraged by the emerging therapeutic profile of our program, that we believe
suits the needs of this global pandemic. Our thanks to our colleagues at the Spiez Laboratory for
working with us in testing our candidates against the live virus. Given the potency we see from these candidates, combined with characteristics of DARPin® therapeutics such as their manufacturability, low immunogenicity and shelf-stability, we are confident in moving to the next phase of work,” said Patrick Amstutz, Chief Executive Officer of Molecular Partners. “We continue to progress this program at high speed and expect to select a clinical candidate in the coming weeks, while we advance our plans for large-scale GMP manufacturing.”
The DARPin® candidates are half-life-extended and contain three distinct monomer DARPin®
proteins that can simultaneously target the virus in different key areas, leading to cooperative
binding and contributing to the extremely high potency now seen in vitro. The approach also allows neutralization of the virus via multiple mechanisms. Another significant advantage of a multi-specific antiviral is its potential ability to protect against viral ‘escape’, whereby a virus may develop resistance to any one antiviral mechanism.
The anti-COVID-19 candidates have subsequently been tested against the live virus, with assistance from the Spiez Laboratory, a division of the Swiss Federal Office for Civil Protection. In the completed 2/3 in vitro potency assessments, dose-response assays with live, infectious SARS-CoV-2 virus showed that the selected candidates had an effective concentration for 50% inhibition (EC50) of less than 100 picomolar (pM) and completely inhibited infectious SARS-CoV-2 virion replication at low tripledigit pM concentrations.
“The DARPin® candidates show potent ant-viral activity against SARS-CoV-2 in our in vitro assay at Spiez Lab. We are looking forward to continue working with the Molecular Partners team on this project,” said Dr. Olivier Engler , Head of Virology at Spiez Laboratory.
From these tests, two candidates have been identified and will now move into in vivo studies, which will begin in May 2020. In parallel, GMP manufacturing is being secured, and the company is preparing for initiation of clinical studies in H2 2020.