Vertex Pharmaceuticals has agreed to acquire biotech Alpine Immune Sciences for $4.9bn, joining the growing number of pharma spending big on immunotherapy-focused companies.

The gene therapy developer will pay $65 for each Vertex shares, around a 67% premium on the US biotech’s stock’s close on 9 April. Rumours of takeover interest surfaced on 10 April via Bloomberg, with the two companies publicly announcing the board-approved acquisition agreement via a press release the same day.

Alpine’s lead asset is povetacicept, a dual agonist of two cytokines – namely B cell activating factor and a proliferation-inducing ligand. The two proteins, called BAFF and APRIL, play a key role in the development of autoimmune diseases.

The biotech is developing the drug, also dubbed ALPN-303, in renal indications and autoimmune cytopenias. Emerging with high promise is the drug’s efficacy in treating immunoglobulin A nephropathy (IgAN), an autoimmune kidney disease.

Vertex’s CEO Reshma Kewalramani says povetacicept is a "potential best-in-class treatment for IgAN."

He added: "We also look forward to fully exploring povetacicept’s potential as a ‘pipeline-in-a-product' and adding Alpine’s protein engineering and immunotherapy capabilities to Vertex’s toolbox."

Alpine states that preclinical studies have shown that its dual agonist approach has demonstrated higher binding affinity and greater potency than single inhibitors of BAFF and APRIL.

Also announced on the same day as the acquisition was data from Alpine’s Phase I/II RUBY-3 trial (NCT05732402) investigating povetacicept in IgAN. After receiving the drug subcutaneously every four weeks at 80mg, patients had a 64.1% reduction from baseline in urine protein to creatinine ratio, indicating an improvement in proteinuria. Proteinuria is usually an indicator of kidney damage.

Alpine said it has had a successful end-of-Phase II meeting with the US Food and Drug Administration (FDA), opening up the development avenue to a Phase III trial, slated to start in the second half of 2024.

Calliditas Therapeutics’ Tarpeyo (budesonide) is currently the only FDA-approved therapy for IgAN, receiving regulatory approval in December 2023. Tarpeyo is indicated for reducing kidney function loss in IgAN patients at risk of disease progression.

Also ramping up development activities in kidney disease is Novartis, which acquired assets – including Fabhalta (iptacopan) from Chinook Therapeutics in a $3.2bn deal in August 2023. Fabhalta hit its interim endpoint in a Phase III trial last October, with Novartis seeking accelerated approval this year.

Vertex’s acquisition adds to a bustling immunotherapy deal landscape in the pharma industry, with AbbVie, Sanofi and Bristol Myers Squibb also completing billion-dollar deals in the space recently.