# R1 Therapeutics

> Clinical-stage kidney-disease therapeutics company developing AP306

## Why it is interesting

R1's Series A grew from $77.5 million to $80.5 million shortly before expected Phase 2b data in the first half of 2027, but only $3 million of the September announcement was incremental.

## Profile

- **Latest funding:** Series A extension — $3M incremental; $80.5M cumulative (September 30, 2026)
- **Latest known valuation:** Not publicly disclosed
- **Total disclosed equity funding:** $81M
- **Stage:** series-a
- **Status:** private
- **Industries:** biotech-life-sciences, healthtech
- **Coverage:** full
- **Last updated:** 2026-10-01
- **Latest funding investors:** Samsara BioCapital

## Key facts

- Series A expanded by $3M to $80.5M on September 30, 2026
- Phase 2b topline data expected in H1 2027
- Samsara BioCapital joined the existing investor syndicate

## Funding history

- Series A extension · $3M incremental; $80.5M cumulative · September 30, 2026
  Source: https://www.streetinsider.com/Globe%2BNewswire/R1%2BTherapeutics%2Bexpands%2BSeries%2BA%2Bto%2B%2480.5%2Bmillion%2Bto%2Badvance%2Bglobal%2BPhase%2B2b%2Bprogram%2Bin%2Bhyperphosphatemia/27125085.html
- Series A · $77.5M · March 2026
  Source: https://www.r1therapeutics.com/

## Investors in our directory

- https://venturecapitaltracker.com/fund/samsara-biocapital
- https://venturecapitaltracker.com/fund/f-prime-capital

**By:** [Venture Capital Tracker](https://venturecapitaltracker.com/editorial-policy)
**Last updated:** October 1, 2026

**Editorial note:** AI tools assisted with research, structure, or drafting. Venture Capital Tracker retains human editorial responsibility for factual accuracy, relevance, and source quality before publication.

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Source: https://venturecapitaltracker.com/startup/r1-therapeutics