Programmable circular "Endless RNA" (eRNA) medicines with AI, from Flagship Pioneering
Sail Biomedicines is a Cambridge, MA RNA-medicines company formed in October 2023 by Flagship Pioneering through the merger of Laronde (Endless RNA / circular RNA) and Senda Biosciences (programmable delivery). Led by CEO Guillaume Pfefer with John Mendlein as executive chairman, Sail pairs a programmable circular-RNA platform with AI-guided design and novel delivery to build durable RNA therapeutics and vaccines.
Biotech📍 Cambridge, MAFounded 2023
Current Valuation
Private
PRIVATE
IPO Outlookprivate
Is Sail Biomedicines going public?
No. Sail Biomedicines is private and has not filed to go public. There is no S-1 on file.
What is Sail Biomedicines' valuation in 2026?
No confirmed valuation is on record for Sail Biomedicines. The roster shows funding and investors where they are public; it does not estimate a mark.
Has Sail Biomedicines filed an S-1?
No public S-1 is on file for Sail Biomedicines.
Who are Sail Biomedicines' investors?
Sail Biomedicines' investors include Flagship Pioneering.
Is Sail Biomedicines publicly traded — can you buy Sail Biomedicines stock?
No. Sail Biomedicines is a private company — its shares are not listed on any exchange and there is no ticker. The routes to exposure are pre-IPO secondary marketplaces and funds (accredited investors), employee tender offers when the company runs one, and public companies with read-through exposure. QuantLogix maps every route it can verify for Sail Biomedicines on its Pre-IPO Access Desk.
Answers are derived from the roster record shown on this page — filing status, last round and confirmed marks. Where the record is silent, the answer says so rather than guessing.
Company Profile
CEO
Guillaume Pfefer
Founded
2023
HQ
Cambridge, MA
Growth
Flagship-funded platform company; pipeline building
IPO Status
private
Fundraising Status
private
Vertical Intelligence — Biotech / Gene Therapy
No name-verified sponsor record on ClinicalTrials.gov for Sail Biomedicines — trials may run under a different legal entity, a partner sponsor, or not yet exist. Absence of a registry match is reported as-is, never guessed around.
Checked clinicaltrials.gov as of 2026-09-27. Re-checked weekly.
Talent Signal
Hiring trend
▲ Hiring uptrend
+80% vs 2026-08
Open roles
9
via greenhouse
Product-build share
89%
engineering, research, product, design
Trajectory
expanding
heavy product build — 89% of open roles are product-building functions (engineering/research/product) — 8 of 9 open roles are research.
No tracked executive churn; open roles trending up.
Open roles by month
Open roles by function
■ product-building ■ go-to-market / G&A
Associate Scientist, Formulation, Pilot LabResearch Associate II, Preclinical ManufacturingScientist IScientist, Platform RNA SciencesSenior Research AssociateSenior Research Associate, High-Throughput RNA Production
Counted from Sail Biomedicines's live job board as of 2026-09-14; role functions classified from posting titles. Open-role counts are an activity signal, not headcount. Refreshed monthly.
Founders & Key People
Flagship Pioneering
Investors
Flagship Pioneering
Products
Endless RNA (eRNA) circular RNA platform
Programmable RNA medicines
Lipid / anellovirus delivery (from Senda)
Competitors
Orbital Therapeutics · Orna Therapeutics · Therna Biosciences
Private-company numbers are not real-time. Reflects publicly disclosed valuations from press releases, news reports, and tender offers as of recent date. Refreshed quarterly.