# Sesen Bio funding: rounds and investors

> Sesen Bio has raised $40M across 1 round since 2018. Investors include JAFCO and Flagship Pioneering. Every round with its source.

Source: https://millionrounds.com/company/sesen-bio (Millionrounds; every figure on the page links to its filing or article)

[Funded startup](https://millionrounds.com/companies)

# Who invested in *Sesen Bio*

One round we have observed, with the 2 investors named in it. Every figure came from a named source, and where the company reported a raise to the SEC itself, that is shown beside it.

Biotech

Funding summary Updated 26 Oct 2026

**$40M** raised across 1 round since 2018, from 1 source

- **Latest round:** Round, $40M Jun 2018
- **Investors:** 2

See who backed them

## The rounds

- **Jun 2018** Round **$40M** [JAFCO](https://millionrounds.com/fund/jafco) [Flagship Pioneering](https://millionrounds.com/fund/flagship-pioneering) Source recorded

## Everyone who backed them

[JAFCO](https://millionrounds.com/fund/jafco) Company **1** round

[Flagship Pioneering](https://millionrounds.com/fund/flagship-pioneering) VC firm **1** round

Missing a round, or an investor who was in one? [Tell us](https://millionrounds.com/corrections?slug=sesen-bio).

## Quick answers about Sesen Bio

### Who invested in Sesen Bio?

Sesen Bio's investors include JAFCO and Flagship Pioneering.

### How much has Sesen Bio raised?

Sesen Bio has raised $40M across 1 round since 2018.

### When did Sesen Bio last raise?

Sesen Bio's most recent round was an Undisclosed round of $40M in Jun 2018.

### What was Sesen Bio's biggest round?

Its most recent round, $40M in Jun 2018, is also its largest on record.

### Who backed Sesen Bio first?

Sesen Bio's first round on record, in Jun 2018, was backed by JAFCO and Flagship Pioneering.

### What stage is Sesen Bio at?

Sesen Bio's latest named round is an Undisclosed round, in Jun 2018.

## Companies like Sesen Bio

In the same sector, and raised in the last eighteen months.

[**Cloverleaf Bio** $33M · Sept 2026](https://millionrounds.com/company/cloverleaf-bio)[**Cheiron** $8.0M · Jul 2026](https://millionrounds.com/company/cheiron)[**Tavo Biotherapeutics** $17M · Jun 2026](https://millionrounds.com/company/tavo-biotherapeutics)[**Countable Labs** $26M · May 2026](https://millionrounds.com/company/countable-labs)[**Oricell Therapeutics** $180M · Apr 2026](https://millionrounds.com/company/oricell-therapeutics)[**Immunofoco** $29M · Mar 2026](https://millionrounds.com/company/immunofoco)

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