More potent. More durable.

Elevated
mRNA for transformative medicines

Engineered to reach therapeutic thresholds that existing mRNA can't.
OVERVIEW
Why existing mRNA falls short

mRNA has already changed medicine. But the next generation of mRNA medicines – therapies that reprogram the immune system, kill tumors, and replace missing proteins – require a step-change in potency and durability. Conventional mRNA can't get there. APEXm™ can.

Technology

APEXm™

Dramatically higher protein expression, sustained for dramatically longer.

APEXm™ (Amplified and Prolonged EXpression mRNA) works differently. Rather than fighting the cell's biology, our platform harnesses it – using proprietary RNA domains to recruit the cell's native stabilizing machinery and drive expression higher, for longer.

Technology
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01
Peak potency

Enhanced protein output to reach therapeutic thresholds that conventional RNA technologies fall short of.

02
Extended durability

Durable protein expression that enables wider dosing windows and sustained therapeutic effect.

03
Universal architecture

A modular mRNA platform that enhances expression of any encoded protein, in any target cell type.

PIPELINE
APEXm™ makes a new class of medicines possible. We're deploying our platform where potency and durability matter most and where other therapies fall short.
LEAD PROGRAM

Autoimmune disease

Dozens of autoimmune diseases share a single root cause: pathogenic B cells. In vivo CAR-T with APEXm™ delivers the depth of depletion needed for true immune reset – and the potential for lasting, drug-free remission.

Oncology

Every cancer is different. In vivo CAR-T with APEXm™ is inherently tunable – programmable control over potency, duration, and redosing tailored to each cancer's unique biology.

Therapeutic proteins

Your cells already make thousands of proteins. APEXm™ teaches them to make one more – a single programmable platform for delivering virtually any therapeutic protein as a durable mRNA medicine.
Our Team

ParcelBio brings together deep expertise in RNA biology, CAR-T cell therapy, and drug development. Our founders have spent decades advancing the science of RNA, and our advisors include leaders across cell therapy, RNA therapeutics, and biotech commercialization.

Backed by Breyer Capital, Y Combinator, General Catalyst, and top life science investors, we're building ParcelBio to bring a new class of mRNA medicines to patients.

David Weinberg, PhD
Co-founder and CEO
Chris Carlson, PhD
Co-founder and CSO
Rachel Green, PhD
Advisor
Stuart Milstein, PhD
Advisor
Robbie Majzner, MD
Advisor
Megan Yung, JD PhD
Advisor
Bret Bostwick, MD
Advisor