Pharma BD Deal Intelligence

Mereo BioPharma Group plc / OncoMed Pharmaceuticals, Inc.

2018 · Reverse Merger · $57M · Complete

The reverse merger gave Mereo BioPharma a Nasdaq listing plus two oncology candidates, but both fizzled—Celgene passed on etigilimab in 2019 and navicixizumab was out-licensed to Oncologie for just $4M upfront. The $57M transaction's real value was the shell listing itself; neither oncology asset ever reached approval.

CALLED IT — OFF BY 23

The Nasdaq listing was the real prize; both OncoMed oncology assets (etigilimab, navicixizumab) fizzled and were out-licensed for token sums, while Mereo's value now rests entirely on unrelated rare-disease assets.

Full analysis, sources & comparables →

The coverage arc

Dec 05, 2018 Endpoints News Bearish

Endpoints framed the deal as Mereo executing a 'back flip onto Nasdaq' by combining with a 'flailing OncoMed,' highlighting the transaction as a low-cost route…

Apr 24, 2019 FierceBiotech Neutral

Post-close coverage emphasized Mereo retained 'a select number of OncoMed employees' and the Redwood City base, with skepticism about whether the navicixizumab…

Oct 07, 2019 GlobeNewswire (Mereo) Bullish

Mereo announced FDA Fast Track designation for navicixizumab in heavily pretreated ovarian cancer following phase 1b data showing 43% ORR with paclitaxel — the…

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

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UK-listed Mereo BioPharma announced December 2018 stock-for-stock reverse merger with US-listed OncoMed Pharmaceuticals to gain Nasdaq listing and add two oncology candidates (navicixizumab anti-DLL4/VEGF bispecific and etigilimab anti-TIGIT). OncoMed shareholders received Mereo ADSs plus contingent value rights, with former OncoMed holders owning ~25% of combined company. Strategically notable as a precedent-setting transatlantic biotech reverse merger structure. Closed April 23, 2019.

Did it work? Outcome assessment

The Nasdaq listing was the real prize; both OncoMed oncology assets (etigilimab, navicixizumab) fizzled and were out-licensed for token sums, while Mereo's value now rests entirely on unrelated rare-disease assets.

Strategic verdict
Failed to Achieve
Financial impact
Neutral
The OncoMed reverse merger (completed April 23, 2019) was structured primarily as a vehicle to give UK-based Mereo a US Nasdaq listing (ticker MREO) and an extended cash runway, rather than as a cash acquisition. Mereo issued ~24.8M new shares; former OncoMed holders received ADSs plus contingent value rights tied to milestone payments. No material write-down was disclosed, but the acquired oncology assets generated little standalone value; Mereo's value creation instead came
Pipeline outcome
Mixed
Of the two OncoMed-derived oncology programs, navicixizumab (anti-DLL4/VEGF) was out-licensed to Oncologie/OncXerna in 2020 (up to ~$300M milestones plus royalties) and largely exited Mereo's active development; etigilimab (anti-TIGIT) continued in a Phase 1b/2 basket study but did not reach pivotal success. Over the window Mereo pivoted strategically to rare disease, where setrusumab (partnered with Ultragenyx) delivered positive Phase 2/3 Orbit data and FDA Breakthrough The

Key facts

Disease & market context

Platinum-Resistant Ovarian Cancer

20K US cases/yr · $1.7B US ovarian cancer drugs market 2024 (44% of $3.84B global)

Disease Overview

Ovarian cancer is the deadliest gynecologic malignancy, with most patients diagnosed at advanced stage and ~70% relapsing within three years of first-line platinum chemotherapy. Platinum-resistant disease (recurrence within 6 months of platinum) carries a particularly poor prognosis and limited treatment options, with response rates to standard salvage regimens typically below 20%.

Competitive Landscape

The platinum-resistant ovarian cancer (PROC) treatment landscape in late 2018 was dominated by anti-angiogenic and PARP-inhibitor classes. Roche/Genentech's Avastin (bevacizumab) plus weekly paclitaxel was the established anti-angiogenic standard following the AURELIA trial, with ORRs near 27%. PARP inhibitors — AstraZeneca's Lynparza (olaparib), GSK/Tesaro's Zejula (niraparib), and Clovis's Rubraca (rucaparib) — captured the BRCA-mutant and HRD-positive maintenance setting but offered limited benefit in heavily pre-treated, bevacizumab-exposed PROC. Single-agent chemotherapies (pegylated liposomal doxorubicin, topotecan, gemcitabine) remained the backbone for late-line patients with poor response rates. Navicixizumab — a bispecific anti-DLL4/VEGF antibody — was differentiated by simultaneously blocking Notch (DLL4) and VEGF angiogenic pathways, with phase 1b data in 44 PROC patients (many bevacizumab pre-treated) showing 43.2% ORR plus paclitaxel, earning FDA Fast Track designation in October 2019. The OncoMed reverse merger gave Mereo Nasdaq access plus this Fast Track-eligible asset; Mereo subsequently out-licensed navicixizumab to Oncologie (now OncXerna) in 2020, signaling Mereo's strategic pivot toward rare disease (setrusumab, alvelestat).

Related deals — scored

DealYearValueOutcome
Mereo BioPharma Group plc / OncoMed Pharmaceuticals, Inc. (this deal)2018$57M27
AstraZeneca PLC / Daiichi Sankyo Company, Limited2019$6.9B100
Novartis AG / Endocyte, Inc.2018$2.1B96
Astellas Pharma Inc. / Seagen Inc.2009$4.5B95
Bristol-Myers Squibb Company / Medarex Inc.2009$2.4B92
Servier / Agios Pharmaceuticals (oncology)2020$2.0B91
Servier Pharmaceuticals LLC / Agios Pharmaceuticals Inc.2020$2.0B91

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