Pharma BD Deal Intelligence

Alexion Pharmaceuticals Inc. / Achillion Pharmaceuticals, Inc.

2019 · Acquisition/Merger · $1.2B · Complete

A rare-disease bet that paid off: Alexion's ~$930M cash deal for Achillion delivered danicopan, later approved as Voydeya in March 2024 for PNH — though Alexion itself had already been swallowed by AstraZeneca by then.

Outcome grade pending — assessed 5 years post-close.

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The coverage arc

Oct 16, 2019 BioPharma Dive Neutral

Analysts flagged FTC scrutiny risk given the overlap between Alexion's complement franchise and Achillion's pipeline, but viewed the oral Factor D mechanism as…

Oct 16, 2019 GEN Bullish

The acquisition expands Alexion's rare-disease portfolio with first-generation oral Factor D danicopan plus a next-gen follow-on, addressing residual…

Apr 01, 2024 OncLive Bullish

FDA approved Voydeya (danicopan) as an add-on to ravulizumab or eculizumab for adults with PNH and clinically significant extravascular hemolysis, validating…

Source summaries from our enrichment pipeline; follow links for originals.

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Alexion acquired Achillion for $6.30 per share (~$930M initial cash consideration) plus non-tradeable CVRs of up to $2.00 per share — $1.00 on FDA approval of danicopan and $1.00 on ACH-5228 (danicopan follow-on) Phase 3 initiation (~$300M maximum). The deal added Achillion's oral Factor D inhibitor portfolio targeting complement-mediated rare diseases (PNH, C3 glomerulopathy) and closed January 28, 2020. The thesis was validated: the FDA approved the lead asset, danicopan (Voydeya), on March 29, 2024 as an add-on to ravulizumab or eculizumab for clinically significant extravascular hemolysis in adults with PNH. By then Alexion had itself been acquired by AstraZeneca (completed July 21, 2021), so Voydeya commercialized under AstraZeneca's Alexion Rare Disease unit.

Did it work? Outcome assessment

Strategic verdict
Partially Achieved
Financial impact
Impaired/Written Down
AstraZeneca (which acquired Alexion in 2021) took a $753M intangible-asset charge announced with FY2024 results in February 2025 upon discontinuing vemircopan, the second Achillion-derived factor D inhibitor - a write-down approaching the deal's ~$930M upfront value.
Pipeline outcome
Mixed
Lead asset danicopan (ALXN2040) was approved by FDA as Voydeya in spring 2024 as add-on therapy to Ultomiris/Soliris for extravascular hemolysis in PNH - a niche add-on rather than a standalone oral franchise. Follow-on factor D inhibitor vemircopan (ALXN2050/ACH-5228) was dropped in PNH in 2023 and fully terminated by early 2025 after Phase 2 efficacy/safety data in lupus nephritis and IgA nephropathy.

Key facts

Disease & market context

Paroxysmal Nocturnal Hemoglobinuria (PNH)

$4.2B Soliris global revenue 2024 (proxy for PNH/aHUS market)

Disease Overview

Paroxysmal nocturnal hemoglobinuria is a rare, acquired, life-threatening hematologic disorder caused by clonal expansion of PIGA-mutant hematopoietic stem cells, leading to complement-mediated red blood cell destruction, thrombosis, and bone marrow failure. It typically affects adults aged 30-40. Untreated, median survival is ~10-15 years; treatment burden on existing IV C5 inhibitors and residual extravascular hemolysis remain key unmet needs.

Competitive Landscape

PNH was historically dominated by Alexion's own Soliris (eculizumab, IV C5 inhibitor, ~$4B+ peak) and its longer-acting follow-on Ultomiris (ravulizumab). Achillion's danicopan (oral Factor D inhibitor) offered Alexion two strategic levers: (1) a defensive oral option as anti-C5 biosimilars approached (Bkemv and Epysqli later launched in 2024) and (2) an add-on for the 10-20% of C5-treated patients with persistent extravascular hemolysis (EVH). The acquisition also brought ACH-5228 (later vemircopan) as a Phase 3-ready next-gen Factor D inhibitor. Competition intensified post-deal: Apellis launched Empaveli (pegcetacoplan, C3 inhibitor) in 2021, demonstrating superiority to Soliris on hemoglobin in PEGASUS, and Novartis advanced iptacopan (Fabhalta, oral Factor B inhibitor, approved 2023). Danicopan was ultimately approved in April 2024 as Voydeya, a first-in-class oral Factor D add-on for EVH, validating the original deal thesis. See https://www.biopharmadive.com/news/alexion-buys-achillion-spurring-concerns-about-ftc/565146/ for FTC overlap concerns at deal time.

Deal timeline

Related deals — scored

DealYearValueOutcome
Alexion Pharmaceuticals Inc. / Achillion Pharmaceuticals, Inc. (this deal)2019$1.2B
Alexion Pharmaceuticals Inc. / Synageva BioPharma2015$8.4B36
Alexion Pharmaceuticals Inc. / Wilson Therapeutics AB2018$855M20
Alexion Pharmaceuticals Inc. / Syntimmune, Inc.2018$1.2B14
Alexion Pharmaceuticals Inc. / Portola Pharmaceuticals, Inc.2020$1.4B
Horizon Pharma plc / Crealta Holdings LLC2015$510M87
Novartis AG / Chinook Therapeutics Inc.2023$3.5B78

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