FSII and Pardes Biosciences Move Towards Merger With the Goal of Tackling COVID-19 via an Oral Antiviral for Treatment and Prevention of SARS-CoV-2 Infections

Proposed merger heads to shareholder vote on December 23rd as ongoing Phase I trial shows potential for unboosted oral regimen

December 21, 2021 SAN FRANCISCO, Calif. & LARKSPUR, Calif.– (BusinessWire) — In advance of the shareholder vote for the business combination between FS Development Corp. II (NASDAQ: FSII) and Pardes Biosciences, Inc. (“Pardes”), the CEOs of both companies are sharing their thoughts on the COVID-19 public health emergency and how they expect the combined company to play an important role in addressing one of the biggest health crises of our time.

“We believe that direct-acting antivirals against coronavirus that are taken orally– such as our PBI-0451 – will become increasingly important in a world where SARS-CoV-2 may become endemic. This eventuality appears more likely with the spread of new highly transmissible variants, such as Delta and Omicron,” said Uri Lopatin, M.D., Chief Executive Officer of Pardes Biosciences. “At Pardes, our aspiration is to be a leader in the development of potential therapies against these types of viruses, starting with PBI-0451 which is in Phase I clinical studies.”

PBI-0451 is a type of antiviral drug called a protease inhibitor. This class of drug has been successfully deployed against diseases such as HIV and hepatitis C. More recently, Pfizer Inc. (“Pfizer”) has helped to demonstrate the potential of their protease inhibitor (when used together with a second drug called ritonavir) to be a potentially important new tool to address the COVID-19 pandemic. This class of drugs has the potential, if taken upon exposure or as treatment when symptoms arise, to lower the risk of hospitalization and death, particularly among individuals who are at higher risk for severe infection, such as those with other medical conditions who are vaccinated but with a poor or diminished immune response or are unvaccinated. The Pardes team believes that oral protease inhibitors are potentially easier to make, transport, and administer than injectable treatments such as antibodies and vaccines, so their manufacture and distribution to patients may face fewer barriers.

Pardes is currently dosing healthy volunteers in a Phase I clinical study of its protease inhibitor, PBI-0451, that is exploring potential dosing levels, intervals and regimens. Topline results are expected to be reported in Q1 2022.

“As we dose escalate, the tolerability and pharmacokinetics to date continue to support the potential for dosing of PBI-0451 as a single agent, without the use of a second ‘boosting’ agent to help increase its levels in the body such as ritonavir, which is used in conjunction with Pfizer’s protease inhibitor (PAXLOVID™). Assuming data from our Phase 1 clinical study continues to support advancement of PBI-0451, we plan to evaluate our tablet formulation in Q1 2022 and – pending regulatory approval – to initiate a Phase 2/3 registrational study in mid 2022,” continued Dr. Lopatin. “We believe that the potential for a simple anti-viral treatment for patients that can be initiated immediately upon diagnosis will be important – especially for those patients with the greatest need, such as the elderly and immunocompromised who often take other medicines for their medical conditions that may be incompatible with drugs like ritonavir.”

“We believe the coronaviral main protease is a key target for SARS-CoV-2 antiviral development as inhibitors of this target are anticipated to have activity against all  currently known variants,” added Jim Tananbaum, M.D., Chief Executive Officer, President and Director of FSII. “Pfizer’s PAXLOVID™ (nirmatrelvir + ritonavir), a boosted protease inhibitor, has demonstrated the impressive potential of this class of drug in humans. We look forward to a world where the COVID pandemic is defeated by a combination of outbreak surveillance, vaccines, and oral antivirals.”

The proposed merger heads to a vote of FSII’s stockholders on December 23, 2021.

About Pardes Biosciences, Inc.

Pardes Biosciences is a clinical-stage biopharmaceutical company created by and for this moment to help solve pandemic-sized problems, starting with COVID-19. We are applying modern reversible-covalent chemistry as a starting point to discover and develop novel oral drug candidates while reimagining the patient journey to access these medicines. The company’s lead product candidate, PBI-0451, is being developed as a direct-acting, oral antiviral drug to treat and prevent SARS-CoV-2 infections, the virus responsible for COVID-19. Pardes Biosciences is committed to innovating every aspect of how we work, including the flexibility of remote working and regional hubs. We are on a mission to stop a pandemic and start a movement so patients everywhere can get well sooner. For more information, please visit www.pardesbio.com.

About PBI-0451

PBI-0451 is an investigational orally bioavailable direct-acting antiviral inhibitor of the coronaviral “main protease” (Mpro), an essential protein required for the replication of all known coronaviruses, including the novel SARS-CoV-2 virus that causes COVID-19. This protease is highly similar across all coronaviruses, including known and emerging coronavirus variants. PBI-0451 is being developed as a direct-acting, oral antiviral drug candidate for the treatment and prevention of SARS-CoV-2 infection and associated diseases.

About FS Development Corp. II (FSII)

FS Development Corp. II, sponsored by Foresite Capital, is a blank check company formed for the purpose of effecting a business combination with one or more businesses in the biotechnology sector. The company is led by Jim Tananbaum, M.D., the CEO of Foresite Capital, an investment firm funding visionary healthcare entrepreneurs with approximately $4 billion in assets under management. The firm is headquartered in the San Francisco Bay Area.


Press Releases