Usman Ahmed
CEO & Chairman
Usman Ahmed is the founder of Quetzal Therapeutics.
Prior to launching Quetzal, Usman served as Chief Executive Officer and member of the Board of Directors at Nexus Pharmaceuticals, LLC, where he played a transformative role in the company’s growth and evolution. He joined Nexus in 2009 as Vice President of Finance and Business Development and quickly rose through the ranks as Chief Financial Officer and ultimately as President & CEO.
During his tenure, Usman led the execution of complex transactions, spearheaded operational improvements, and championed cost efficiencies in the highly specialized and challenging field of generic injectables. He was instrumental in building high-performing teams and navigating the organization through periods of rapid change and growth. In 2024, under his leadership, Nexus successfully divested its cutting-edge pharmaceutical manufacturing facility.
Before joining Nexus, Usman began his career as an Associate at J.P. Morgan, where he gained foundational experience in finance and investment strategy. He holds a Bachelor of Science in Finance from The Ohio State University.
Today, Usman brings the same drive and vision to Quetzal Therapeutics, fueled by his deep industry experience and a personal mission to advance health through purpose-driven innovation.
Sridhar Desikan
Co-Founder, Chief Scientific Officer
Sridhar Desikan, Ph.D., is a Pharma Industry veteran with 28 years of experience in NCE and Generics development. He began his career at Novartis Pharmaceuticals and subsequently worked at DuPont Pharma and Bristol-Myers Squibb, contributing to the development and commercialization of Efavirenz (Sustiva™) for HIV/AIDS. At DuPont Pharma, he was involved in the development of Factor Xa candidates, leading to Apixaban (Eliquis™). Sridhar was part of the BMS site leadership in Bengaluru, India, establishing drug discovery/early phase development capabilities across multiple therapeutic areas. At Dr. Reddy’s and Nexus Pharmaceuticals, he led R&D teams for complex generics and injectables. Sridhar holds a Ph.D. in Chemical Engineering and has accreditations from Harvard Medical School’s HMX Pro program.
Sara Mathews
Vice President, Program Leadership
With nearly 15 years of experience in the biotech industry, Sara is a seasoned asset leader with a proven track record of bringing cross-functional teams together and leading novel oncology therapeutics through global clinical programs from IND filing through late-stage development, filing preparation, and commercial launch planning. Sara has deep oncology experience in solid tumors and hematologic cancers overseeing the strategic decision-making and operational execution of large global programs. Prior to joining Quetzal Therapeutics, Sara spent 6 years at Syros Pharmaceuticals and 6 years at Merrimack Pharmaceuticals and has served in a number of roles across the cross-functional matrix of a drug development team, including program leadership, program and portfolio management, clinical science, and clinical operations. With a focus on program and portfolio strategy, Sara also led Business Development initiatives for Syros, successfully securing out-licensing opportunities and development partnerships.
Christina Liwski
General Counsel and Chief Human Resources Officer
Christina brings over a decade of diverse and sophisticated legal experience to her role as General Counsel, where she oversees all legal and HR matters across the organization and serves as a strategic advisor to the executive leadership team.
Before joining Quetzal Therapeutics, Christina served as Assistant General Counsel at Nexus Pharmaceuticals, where she played a pivotal role in managing legal operations across domestic and international pharmaceutical activities. Her work included leading complex commercial contracting efforts, intellectual property management, litigation strategy, and corporate transactions, while also advising cross-functional teams in finance, R&D, regulatory, quality assurance, and marketing.
Prior to that, Christina served as Senior Corporate Counsel at the US- based subsidiary of an international technology company where she advised on high-value, multi-jurisdictional commercial technology agreements and provided legal guidance on data privacy, employment, insurance, and litigation matters.
Earlier in her career, Christina held key legal roles at prestigious law firms and in government. At Ropes & Gray LLP, she worked within the General Counsel’s Office, focusing on compliance, ethical conflicts, and corporate risk management. She also practiced as an Associate Attorney at Morrison Mahoney LLP, handling civil litigation, and as a Trial Attorney for the Commonwealth of Massachusetts, where she gained extensive courtroom experience representing clients in criminal proceedings, having served as first chair in multiple trials, motions, and other hearings.
Christina is known for her collaborative approach, deep legal acumen, and ability to navigate complex regulatory environments. Christina is admitted to practice in Illinois, Massachusetts, and the United States District Court for the District of Massachusetts.
Aman Ahmed
Board Member
Aman Ahmed is the Co-Founder of Quetzal Therapeutics, a company built on a shared vision to advance healthcare innovation through purpose-driven solutions.
Prior to co-founding Quetzal, Aman began his career at Nexus Pharmaceuticals, LLC in 2017, where he currently serves on the Board of Directors. As Director of International Sales, he led the company’s global business development efforts, managing an extensive product portfolio across multiple international markets.
With nearly a decade of experience in the pharmaceutical industry, Aman brings deep expertise in sales operations, DEA and FDA regulatory compliance, inside sales, and therapeutic portfolio management. He played a key role in the strategic expansion of Nexus’s manufacturing footprint in Pleasant Prairie, culminating in the successful divestiture of the facility to Eli Lilly.
Beyond his operational leadership, Aman is also an active investor with interests in healthcare, sustainability, and entertainment. He holds a Bachelor of Science in Healthcare Management and Policy from Indiana University.
Dr. Jonathan Cheng
Board Member, Chief Medical Officer Systimmune
Dr. Jonathan Cheng is a physician-scientist and oncology drug development expert with a distinguished career across both industry and academia. As Chief Medical Officer at Systimmune, he leads the clinical development of a diverse pipeline of novel therapeutics, including innovative antibody-drug conjugates (ADCs) and the company’s first-in-class EGFR-HER3 bispecific ADC currently in Phase 3 trials.
Dr. Cheng previously held senior leadership positions at Bristol Myers Squibb and Merck, where he was instrumental in the development and global approval of transformative cancer therapies such as Nivolumab, Ipilimumab, Relatlimab, Pembrolizumab, and Lenvatinib. He has led numerous global regulatory submissions and agency interactions, shaping oncology portfolios and advancing dozens of indications across solid and hematologic malignancies.
Before transitioning to industry, Dr. Cheng was an Associate Professor at Fox Chase Cancer Center, where he ran an NIH-funded research program focused on tumor stromal biology. He continues to see patients with gastrointestinal cancers as part of the GI Oncology group at Fox Chase.
Dr. Cheng earned his BS from Marquette University and his MD from the University of Minnesota.
Todd Chermak, R.Ph., Ph.D.
SVP and Global Business Head Immunology and Proteomics CellCarta
Todd is a life sciences executive with 30 years of experience spanning the biopharmaceutical, diagnostics, and nutrition industries. He currently serves as Senior Vice President and Global Business Head of Immunology and Proteomics at CellCarta, where he leads global teams advancing biomarker discovery and precision medicine solutions.
Before joining CellCarta, Todd spent over two decades at Abbott in roles of increasing responsibility across R&D, Quality and Regulatory Affairs. His career reflects a broad and practical understanding of product development, regulatory strategy, and business leadership in complex, highly regulated environments.
In addition to his role on the Quezal board, Todd serves as a board member for ATCC, a nonprofit organization that supports global scientific research through the development and distribution of biological materials. He has also contributed to various academic and industry advisory boards, including the Regulatory Affairs Professionals Society (RAPS), the International Life Sciences Institute, and the Dean’s Advisory Board at Purdue University’s College of Pharmacy. He was named a Ford Scholar by Northwestern University’s Kellogg School of Management.
Todd holds a Ph.D. in Pharmacy from the University of Illinois, a Master’s degree in Engineering and Management Sciences from Northwestern University, and a Bachelor of Science in Pharmacy from Purdue University. He also holds certifications in Regulatory and Quality Compliance and is a Lean Six Sigma Green Belt.
Mike Warmuth
Board Member
Mike Warmuth is currently working on various Boards: for profit, academic and not-for-profit. Prior to that, Mr. Warmuth worked for EW Healthcare as an Operating Partner in the New York office from May 2018 until January 2023. Mr. Warmuth has spent his entire career with Abbott Laboratories, having joined on the manufacturing development program immediately after university.
He spent five years as Executive Vice President, leading the Established Pharmaceuticals division, which is a leader in the sale of branded generics in emerging markets. The Established Pharmaceuticals division of Abbott is in the top ten largest generics companies globally, with revenues of >$4 billion. Mr. Warmuth held full P&L responsibility for this division, which covers several therapeutic areas including gastroenterology, women’s health, cardiovascular and metabolic disorders, pain and CNS, and respiratory drugs and vaccines. During his tenure, he led multiple M&A transactions at Abbott, including the acquisition of Chile-based CFR Pharmaceuticals for $2.9 billion in May 2014, followed by Russian pharmaceutical company, Veropharm, for $631 million in June 2014, as well as Piramal Healthcare’s prescription business for $3.7 billion in 2010, which added 350 drugs to Abbott’s portfolio.
Prior to Established Pharmaceuticals he spent almost three years as the Senior Vice President of Diagnostics, running Abbott’s global core laboratory diagnostics business. Prior thereto, Mr. Warmuth spent a brief period as GM for the Hematology division within the Diagnostics business unit. Before this, he was Vice President of the Global Engineering Services business. From 2004 to 2006, he was Division VP, Operations for the Quality and Global Pharmaceutical Operations team.
Mr. Warmuth received his Bachelor’s degree in Business Administration from the University of Wisconsin-Whitewater and his Master’s degree in Business Administration from Northwestern University.
