Pharma BD Deal Intelligence
Sanofi acquired Synthorx for $2.5B for IL-2 cancer immunotherapy.
Sanofi dropped its IL-2 candidate SAR444245 (THOR-707) Phase 2 3-week dosing schedule citing lower-than-projected efficacy; ~$1.6B impairment charge.
THOR-707/SAR444245 solid-tumor study NCT04009681: overall status TERMINATED — 'terminated as per Sponsor decision... not related to any safety concerns.'…
Source summaries from our enrichment pipeline; follow links for originals.
All 10 sources with sentiment breakdown →
Sanofi acquired San Diego-based Synthorx for $68/share, ~$2.5 billion in cash, to anchor its immuno-oncology pipeline under then-new CEO Paul Hudson. The deal (announced December 9, 2019; closed January 23, 2020) was built around THOR-707 / SAR444245 (tenxilvunakin), an engineered 'not-alpha' PEGylated IL-2 designed to bias signaling toward CD8+ T and NK cells while avoiding regulatory-T-cell activation. The thesis did not pan out. In October 2022 Sanofi halted the Phase 2 platform's every-3-week dosing after efficacy came in 'lower than projected' and booked a ~EUR1.6 billion (~$1.6B) impairment, then ran a Phase 1/2 dose-intensification salvage program. In the fourth quarter of 2024 Sanofi removed SAR444245 from its R&D pipeline entirely; the lead solid-tumor study (NCT04009681) and the Pegathor Lymphoma study (NCT05179603) are both terminated per a strategic sponsor decision (not safety-driven), as verified on ClinicalTrials.gov in December 2025. The $2.5B acquisition is effectively a write-off.
| Deal | Year | Value | Outcome |
|---|---|---|---|
| Sanofi SA / Synthorx Inc. (this deal) | 2019 | $2.5B | 15 |
| Sanofi SA / Regeneron Pharmaceuticals, Inc. | 2007 | $1.0B | 97 |
| Sanofi SA / Synthelabo S.A. | 1998 | $11.0B | 84 |
| Sanofi SA / Genzyme Corporation | 2011 | $20.1B | 84 |
| Sanofi SA / Amunix Pharmaceuticals Inc. | 2021 | $1.2B | 76 |
| Sanofi SA / Genzyme Corporation | 2010 | $18.5B | 75 |
| Sanofi SA / Translate Bio Inc. | 2018 | $805M | 73 |
← Browse all deals · How we score deals
More: 2019 deals · Sanofi SA deals · Oncology deals