Funding profile · Antimicrobials

Felix Biotechnology

A phage therapy company with no Form D on file, $2.05 million in traceable non dilutive funding, and a licensing deal a public partner said was conditional on a Series A that never appears in any record.

$1.05MFederal SBIR and STTR awards on record, NSF and NIH
$1.0MCystic Fibrosis Foundation Therapeutics Development Award, 2022
NoneForm D offerings filed with the SEC, as of Sep 23, 2026
$281MMilestone value of a licensing letter of intent never made definitive

Data as of September 23, 2026. Company-reported figures are labeled.

Rounds at a glance

When Round Amount Investors Source
Winter 2020 Y Combinator batch Not disclosed Y Combinator YC directory
By Jan 2021 Seed, size never published Not disclosed Y Combinator, Illumina Accelerator, Point72 Ventures Company release
Jun 2021 NSF SBIR Phase I, award 2126731 $256,000 National Science Foundation Public record
Apr 2022 to Jan 2024 NIH SBIR and STTR Phase I $798,835 NIAID (R41AI165185), NIGMS (R43GM146502) Public record
Mar 2022 Therapeutics Development Award $1,000,000 Cystic Fibrosis Foundation Independent
Never announced Series A None found None Not found

What the filings show

Felix Biotechnology, Inc. · no Form D on record

Company search
An SEC company name search returns no registrant called Felix Biotechnology
Full text search
15 EDGAR documents mention the name, all filed by other issuers
Form D hits
Zero
Checked
SEC EDGAR, Sep 23, 2026

TFF Pharmaceuticals, Inc. · Form 8-K exhibit · filed Mar 24, 2022

Subject
Letter of intent with Felix, signed Nov 5, 2020
Terms
Worldwide license to a dry powder formulation technology, for an upfront payment, milestones worth up to $281 million, and royalties
Condition
A definitive agreement was subject to conditions including Felix completing a Series A financing
Status in filing
Still described as a letter of intent, 16 months after signing
Filing
SEC EDGAR, CIK 0001733413

Reading the filings

  1. The absence of a Form D is the main filing fact.A company raising under Regulation D must notice the offering within 15 days of the first sale. Felix noticed none across seven years, so the seed capital named in its releases came in under another exemption, or through accelerator instruments the accelerator itself filed, or it was never large.
  2. Everything countable is non dilutive.$1,054,835 in federal grants plus the $1 million Cystic Fibrosis Foundation award is $2.05 million with a paper trail. No venture round size has ever been published, so the equity side cannot be sized from public sources.
  3. A public partner disclosed the financing condition.TFF Pharmaceuticals told its shareholders that the definitive license depended on Felix completing a Series A. TFF slides filed through March 2022 still call it a letter of intent, the clearest public signal that the round did not close.
  4. Grant money stopped at Phase I.Three Phase I awards, two agencies, zero Phase II follow ons, the last ending January 31, 2024. Phase II is the usual filter in these programs, and Felix did not clear it at either agency.
  5. The clinical program shrank to a fifth of its announced size.Announced at 36 patients, the registry reports 8, about 22 percent of plan, enrollment ended November 2022. A trial that small cannot support a financing, and a financing that does not close cannot support a larger trial.
  6. The wind down is recorded in a journal, not a filing.A January 2026 PNAS paper co-authored by two former employees and two former co-founders discloses Felix as a company that is no longer operating. Nothing in EDGAR marks the end, because nothing marked the beginning.

Commercial signals

Signal Detail Source type
Regulatory No FDA approval, clearance or licensure. No phage therapy is approved in the United States. Public record
Clinical NCT04684641, Yale sponsored, 8 patients enrolled, results posted Mar 2023, study completed Jun 2023. Public record
Partnerships TFF Pharmaceuticals letter of intent, never made definitive. AnimalBiome pet health collaboration, Jan 2022, no product announced. Partner-stated
Peer position Armata Pharmaceuticals named Felix in its fiscal 2023 Form 10-K as one of a handful of companies developing phage products for human disease. Public record
Status Y Combinator lists the company as inactive, team size 6. YC directory

What to watch

  • Any assignment or license record showing the Yale intellectual property moving to a new holder.
  • Whether the Cystic Fibrosis Foundation reports an outcome on its $1 million award.
  • Whether TFF Pharmaceuticals discloses a termination of the letter of intent.
  • New EDGAR registrants tied to the founders, which would be the first sign of a successor vehicle.

The Felix Biotechnology story on Healthcare DiscoveryHealthcare Discovery

Related companies

  • Invitris: Also in Drug Discovery and Delivery. A Munich spinout making protein-based drugs, bacteriophages against drug-resistant bacteria first, without living cells
  • CellType: Also in Drug Discovery and Delivery. A two person Yale spinout that translates single cell biology into a language large models can learn, and is using that model to steer a real cancer drug's next act
  • Matrubials: Also in Drug Discovery and Delivery. A UC Davis spin-out turning antimicrobial peptides found in human milk into a topical drug for bacterial vaginosis
  • Macromoltek: Also in Drug Discovery and Delivery. An Austin software company that has designed antibodies inside a computer since 2011, paid for by federal grants and customer fees rather than venture rounds

Sources

  1. Public recordSEC EDGAR company name search and full text search, Felix BiotechnologySEC · Sep 23, 2026
  2. Public recordTFF Pharmaceuticals corporate presentation, Form 8-K exhibit 99.2SEC · Mar 24, 2022
  3. Public recordArmata Pharmaceuticals Form 10-K for fiscal 2023, competition sectionSEC · Mar 21, 2024
  4. Public recordNSF award 2126731 and NIH RePORTER R41AI165185 and R43GM146502NSF and NIH · 2021 to 2024
  5. Public recordClinicalTrials.gov NCT04684641, CYPHY, with posted resultsClinicalTrials.gov · Mar 3, 2023
  6. Public recordA fully synthetic Golden Gate assembly system for engineering a Pseudomonas aeruginosa phiKMV-like phage, competing interests statementPNAS · Jan 27, 2026
  7. IndependentCF Foundation Awards $1 Million to Felix Biotechnology to Develop Novel Phage TherapyGlobal Genes · Mar 3, 2022
  8. CompanyFelix Biotechnology announces initiation of the CYPHY Phase 1/2 study at YalePR Newswire · Jan 7, 2021
  9. PartnerTFF Pharmaceuticals and Felix Biotechnology Sign Letter of IntentBusiness Wire · Nov 5, 2020

Compiled from SEC, NSF, NIH and ClinicalTrials.gov public records and published reports as of September 23, 2026. Form D notices report offerings under Regulation D; the absence of a notice does not prove that no capital was raised. Healthcare Venture Capital Fund holds no position in Felix Biotechnology. This page is not an offer to sell or a recommendation to buy any security.