Dee
Datta

The Switch Setter

There is a moment in most biotech origin stories when someone looks at a decade of promising lab science and decides to build a company around it. Dee Datta had that moment in 2020 - in the middle of a pandemic - when she co-founded Switch Therapeutics to commercialize RNA interference discoveries from Caltech, Harvard Medical School, and City of Hope. The catch: the platform did not yet exist as a medicine. It barely existed as a concept anyone had tried to scale.

That is the kind of bet that requires either recklessness or a very specific kind of fluency. Datta has the latter. She holds a Ph.D. from Caltech - the same institution whose research sits at Switch's scientific core - and an MBA from Stanford's Graduate School of Business. Before she ran a company, she evaluated companies for a living, as a venture capitalist at Longitude Capital and The Column Group, two of the more rigorous life sciences investment firms working in the US market. She knows both how to read a balance sheet and how to read a data package.

After venture capital, she moved to the operating side. At XOMA - the specialty royalty company - she served as Chief Business Officer, closing licensing deals with Novartis and Novo Nordisk. Before that, as VP of Corporate Development at Forty Seven, Inc., she managed company financings, strategy, and business development for a company that was eventually acquired by Gilead Sciences for $4.9 billion in 2020. Each role taught her something the next one required.

The CASi Platform: What "Conditionally Activated" Actually Means

Most RNA interference drugs have a delivery problem. siRNA molecules - the short, gene-silencing workhorses of the field - don't naturally know where to go. Getting them into the right cell type, in sufficient quantity, without triggering side effects in liver or immune tissue, has occupied the field for two decades. Switch's answer is CASi: Conditionally Activated siRNAs.

The core insight is structural. CASi molecules combine properties of both single-stranded and double-stranded RNA in a single engineered molecule. Single-stranded RNAs are better at self-delivery - they navigate cell membranes more easily. Double-stranded RNAs are more potent silencers once inside the cell. CASi captures both, but with a conditional twist: the silencing activity only switches on in specific target cell types. The molecule effectively waits until it is in the right environment before activating.

The practical consequence is a brain-targeted therapy that largely bypasses the liver - which is not incidental. The liver is where most RNA medicines end up. Keeping it out of there is the difference between a drug that can hit the brain and one that cannot.

The APOE4 Thesis

In December 2024, Switch named its first development candidate: CASi-APOE. The target is the APOE4 genetic variant, which is present in approximately 25% of the general population - but in 60% of Alzheimer's disease patients. That number is not incidental to the strategy; it is the strategy. APOE4 carriers have significantly elevated risk of developing Alzheimer's and often develop it earlier. Reducing APOE levels in the brain, preclinical data suggests, may lower both amyloid-beta and tau - the two pathological hallmarks of the disease.

The "liver-sparing" element matters here because APOE plays a critical role in lipid metabolism in the liver. A therapy that knocked down APOE systemically would disrupt normal liver function. Switch's CASi-APOE is engineered to act selectively in the brain while leaving hepatic APOE largely intact. IND-enabling studies are underway. Phase 1 clinical trials are planned for 2026.

To support its Alzheimer's neuroscience push, Switch recruited David M. Holtzman, M.D. - director of both the Hope Center for Neurological Disorders and the Knight Alzheimer's Disease Research Center at Washington University in St. Louis, and a member of the National Academy of Medicine - to its Scientific Advisory Board.

The $52 Million Vote

In March 2023, Switch publicly launched after closing a $52 million Series A financing. The round was co-led by Insight Partners and UCB Ventures. Also investing: Upfront Ventures, BOLD Capital Partners, Eli Lilly and Company, Ono Venture Investment, Digitalis Ventures, Dolby Family Ventures, Free Flow Ventures, and PhiFund Ventures.

The presence of Eli Lilly - a company with deep Alzheimer's disease investments and the maker of FDA-approved amyloid-clearing therapy donanemab - is not decorative. Lilly's participation signals that a major pharmaceutical player sees strategic value in what Switch is building, either as a complementary approach to amyloid clearance or as a potential acquisition and partnership target.

Investor, Then Builder

Datta's time on the VC side of the table was not a detour. It was preparation. At Longitude Capital, she developed expertise in alternative financing structures - royalty monetization, in particular - that have become increasingly important tools for emerging biotechs managing cash runways and non-dilutive capital. At The Column Group, she gained early-stage portfolio formation experience: understanding which scientific bets are worth placing and which teams can execute.

That dual literacy - the scientist who can read a financial model, the investor who can read a PCR result - is rarer than it appears. It also shaped how Switch was built. The company was not spun out of a university lab looking for someone to run it. Datta co-founded it with clear strategic intent: specific science, specific diseases, specific platform advantages that competitors would find hard to replicate quickly.

A Company Built During Lockdown

Switch Therapeutics was founded in 2020. By any measure, founding a biotech company in the middle of a global pandemic - with supply chains disrupted, lab access constrained, and investor attention diverted - required a particular kind of persistence. The company spent its first three years in stealth, doing the scientific work quietly before its March 2023 public debut. Thirty employees. A focused pipeline. A platform that the company's investors have collectively staked $75 million on across its financing history.

Outside the lab and boardroom, Datta is known to travel extensively with her husband and daughter - a grounding habit for someone running a company that spends its days thinking about molecules measured in nanometers and diseases measured in decades.