Ep167: Leslie Williams on transfer RNA therapies

Episode Summary

Executive Summary: Leslie Williams traces her path from small-town Iowa nursing and pharma sales to biotech CEO, showing how patient-facing experience shaped her leadership. She explains HC Bioscience’s RNA medicine platform using engineered tRNA in lipid nanoparticles to read through premature stop codons and restore full-length proteins, with lead programs in hemophilia A and Duchenne muscular dystrophy and clinical trials planned for late 2025.

Main Topics: Leslie Williams’ personal and professional origin story (Priority: 5/5): Raised in Gowrie, Iowa, Williams developed early business, science, and customer-service instincts working in her father’s electronics store, then pursued nursing at the University of Iowa before moving into critical care. Patient-facing experience as a foundation for biotech leadership (Priority: 5/5): Her ICU and cardiac-care work exposed her to life-and-death decision-making, patient families, and the real-world impact of therapies, shaping her patient-first perspective as a CEO. Career progression through pharma, business school, and startup formation (Priority: 4/5): Williams moved from Glaxo and Merck into entrepreneurship, learning drug development across clinical, regulatory, commercial, and policy dimensions at INO Therapeutics and later leading other companies. HC Bioscience’s tRNA platform and mechanism of action (Priority: 5/5): The company is developing minimally engineered tRNA therapies delivered via lipid nanoparticles to overwrite premature termination codons, enabling cells to produce full-length functional proteins. Lead indications and clinical strategy (Priority: 5/5): HC Bioscience’s initial programs target hemophilia A and Duchenne muscular dystrophy, with broader potential across many nonsense-mutation diseases; trials are planned for late 2025 with early patient data expected in early 2026. Drug delivery, durability, and redosing advantages (Priority: 4/5): Williams emphasizes lipid nanoparticle delivery, nuclear expression from non-integrating DNA, and the possibility of redosing—an advantage over many gene therapies constrained by immunogenicity. Leadership support and the Biotech CEO Sisterhood (Priority: 3/5): Williams describes the sisterhood as a peer network that reduces the loneliness of the CEO role, offers practical advice, and helps support the next generation of women leaders.

Key Arguments: Williams argues that her ICU background makes her a better CEO because it keeps the patient and family impact of every decision front and center. She says her path into biotech entrepreneurship was driven less by formal career planning and more by curiosity, problem-solving, and a desire to address unmet medical needs. HC Bioscience’s tRNA approach is gene-agnostic and mutation-specific: the same platform can potentially address any nonsense mutation regardless of gene or disease. Unlike exon-skipping approaches that produce shortened proteins, HC Bioscience aims to restore authentic full-length proteins by reading through premature stop codons. The company believes its platform could be broadly applicable because an estimated 10-15% of inherited diseases involve premature termination codons. A key advantage over viral gene therapy is redosing potential, since the platform is designed to avoid the immunogenicity barriers that often limit AAV-based approaches. The company’s early oncology program taught it to follow biodistribution data and pivot to diseases where delivery naturally matched biology, such as hemophilia A in liver sinusoidal endothelial cells. Peer support from other biotech CEOs is important because leadership can be isolating and benefits from candid, experienced sounding boards.

Data Points: Population of Gowrie, Iowa: 2,000 people - Williams’ hometown in rural Iowa Estimated share of inherited diseases caused by premature termination codons: 10-15% - Broad potential market for tRNA-based nonsense-mutation therapies HC Bioscience lead-program launch timing: Late 2025 - Scheduled start of clinical trials First patient data timing: Early 2026 - Expected initial results from early trials Hemophilia A nonsense-mutation subset: About 20% - Patients with severe hemophilia A that HC Bioscience is targeting Duchenne muscular dystrophy nonsense-mutation subset: About 12% - Potential patient subgroup for the DMD program Durability seen in animal models: 3 months - Observed duration of effect so far for the platform Factor VIII threshold for normal levels: Above 40% - Williams noted this as the normal range in hemophilia A Target factor VIII restoration in hemophilia A trials: At least 30% - Desired early clinical benchmark Moderator/therapeutic dosing interval target: Once every 3 months to once every 6 months or less frequent - Projected redosing window for the platform INO Therapeutics team size at start: One of the first 6 employees - Williams’ early role in developing inhaled nitric oxide INO Therapeutics revenue milestone: $100 million - Commercial scale reached during her tenure Year nitric oxide Nobel Prize recognition: 1998 - Awarded for discovery of nitric oxide’s vasodilatory role Year Williams joined the nitric oxide company: 1996 - Early-stage phase of her biotech career

Pivotal Quotes: "it’s really patient first" — Leslie Williams: Explaining how ICU experience shaped her approach as a biotech CEO "I like big ideas" — Leslie Williams: Describing why the tRNA platform and its broad potential attracted her "this is an informational drug" — Leslie Williams: Describing hemophilia A as a setting where early biomarker readouts can show whether the platform works

Implications: If successful, HC Bioscience could open a broad new class of redosable RNA medicines for nonsense-mutation diseases, with faster biomarker-based de-risking in the clinic. The platform could complement or outperform gene therapy in select patients by restoring authentic proteins.