Inside CSL’s strategy to simplify a biotech giant 

CSL does not fit neatly into the typical biotech strategy mold. While much of the industry’s attention is focused on artificial intelligence (AI) drug discovery, obesity medicines, antibody-drug conjugates, or next-generation cell therapies, the Australian biotech giant has built its position around something less eye-catching but hard to replicate: plasma collection, protein science, vaccines, and specialty medicines for rare and serious diseases. 

After years of expansion, including the acquisition of Vifor Pharma and the growth of its Seqirus vaccine business, the company is moving into a phase defined by focus. In August 2025, CSL announced plans to demerge Seqirus into a separate ASX-listed vaccine company before the end of 2026, while also launching a broader restructuring program aimed at reducing complexity, closing underperforming plasma centers, and cutting up to 15% of its workforce. 

The strategic reset has also come with a leadership change. In February 2026, Paul McKenzie stepped down as chief executive, with long-time CSL executive Gordon Naylor appointed interim CEO and given the task of executing the company’s transformation. At the same time, CSL has continued to pursue targeted external innovation, including recent option-based deals with VarmX in coagulation and Memo Therapeutics in recombinant polyclonal immunoglobulins. 

The company appears to be entering a phase of selective refocusing, simplifying a business that had expanded across plasma therapeutics, vaccines, nephrology, and specialty medicines over the past decade. 

The plasma moat remains central to CSL’s strategy Back to Top

For all the discussion around CSL’s restructuring, the company’s strategic center of gravity has not really changed. CSL Behring, its plasma-derived and recombinant therapeutics division focused on rare and serious diseases, remains the group’s largest business and the clearest expression of what has historically made CSL difficult to replicate. 

In the first half of fiscal year 2026, CSL Behring generated $5.45 billion in revenue, more than CSL Seqirus and CSL Vifor combined. That figure was down 7%, so there’s pressure on the business, but it also showed how central Behring remains to the company’s overall shape. Immunoglobulins alone accounted for more than half of Behring’s sales, with IVIG (intravenous immunoglobulin) revenue of $1.99 billion and SCIG (subcutaneous immunoglobulin) revenue of $1.05 billion. 

In the same period, CSL Behring generated $746 million from hemophilia products, $494 million from albumin, $405 million from perioperative bleeding products, and $424 million from hereditary angioedema therapies.  

In addition to developing drugs, the company controls much of the industrial system needed to supply them. CSL says it is one of the world’s largest collectors of human plasma, with plasma collection centers in the U.S. and Europe, and uses that plasma to manufacture therapies supplied to patients in more than 100 countries. In a field where supply and manufacturing scale are as important as innovation, this infrastructure is a considerable asset in itself. 

However, plasma-derived therapies require a large donor network, complex manufacturing, and strict quality systems. In 2025, CSL’s quality systems, plasma collection, and manufacturing operations were subject to 403 regulatory agency inspections, most of them at plasma collection centers, although the company said none of these inspections resulted in a critical finding that would have delayed or prevented the release of commercial products. 

The problem with complexity Back to Top

After years of building a broader business across plasma therapeutics, vaccines, nephrology, and specialty medicines, CSL is now trying to make the group easier to manage. 

The clearest example is CSL Seqirus, the company’s vaccines business. In August 2025, CSL announced plans to demerge Seqirus into a separate company, arguing that the vaccines unit would benefit from greater autonomy while the remaining CSL group would become simpler and more focused. CSL described it as a global leader in seasonal influenza vaccines, with a differentiated portfolio built around cell-based and adjuvanted technologies. The issue was whether a vaccines business exposed to different market dynamics still belonged inside the same operating structure as CSL’s plasma and rare disease businesses. 

CSL has also reduced its research and development (R&D) footprint from 11 sites to six, integrated the commercial and medical teams of CSL Behring and CSL Vifor, and will close 22 underperforming plasma collection centers in the U.S. The company has also said the broader program will lead to a net reduction of up to 15% of its workforce. 

CSL’s historical strengths are operationally intensive, plasma collection, biological manufacturing, regulatory quality systems, and specialized commercial networks. Adding vaccines, nephrology and new therapeutic platforms may diversify the business, but it also creates more moving parts. 

Seqirus: key asset, different market in CSL’s strategyBack to Top

The vaccines division remains a major influenza player, and CSL has emphasized its differentiated position in cell-based and adjuvanted vaccines. In August 2025, when CSL announced its intention to demerge Seqirus into a separate ASX-listed company, the motivation was that vaccines may need a different operating model from CSL’s plasma therapeutics and rare disease businesses. 

Seasonal influenza vaccines are exposed to dynamics that look very different from CSL Behring’s core business, annual immunization rates, public health policy, tendering, pricing pressure, and strain selection. The company said the U.S. 2025/26 seasonal influenza vaccine market value was expected to fall by around 6 to 8%, due to lower immunization rates and pricing pressure. 

The business gives CSL a strong position in vaccines, pandemic preparedness, and differentiated influenza technologies. But it also introduces a market cycle that does not necessarily move in line with plasma-derived therapies, immunoglobulins, nephrology, or rare disease products. 

The planned demerger has already shown that tension. CSL initially targeted a separation before the end of its 2026 financial year, arguing that Seqirus would benefit from more autonomy while the remaining CSL group would become simpler and easier to manage. But in October 2025, the company said the demerger would be delayed until market conditions better supported shareholder value, after U.S. flu vaccination rates fell more sharply than expected. CSL nevertheless said the strategic value of the separation remained strong.  

The vaccine business also shows the complexity of innovation after COVID-19. CSL and Arcturus received European Commission approval in 2025 for KOSTAIVE, the first self-amplifying mRNA COVID-19 vaccine approved by the EC. In theory, this gave Seqirus exposure to a next-generation vaccine platform beyond traditional influenza. However, the vaccine ended up being dropped a few weeks after the Pfizer-BioNTech vaccine was approved because it was provoking false-positive HIV diagnoses, and CSL later recorded a $566 million impairment related to the self-amplifying mRNA platform. 

Vifor shows the limits of CSL’s diversification strategy Back to Top

If Seqirus shows why CSL is trying to reduce complexity, Vifor shows why the company became more complex in the first place. CSL’s acquisition of Vifor Pharma was the clearest attempt to move beyond its historical plasma and vaccines base. 

When CSL announced the deal in 2021, Vifor was meant to expand CSL’s revenue base, strengthen its position in renal disease and iron deficiency, and open new adjacencies in nephrology, dialysis, and cardio-renal medicine. The acquisition also brought a portfolio of commercial products, including Ferinject/Injectafer, Venofer, and Veltassa, as well as access to Vifor’s nephrology network and business development model. 

In the first half of 2026, CSL Vifor generated $1.2 billion in revenue, up by 12%. Unlike CSL Behring and Seqirus, Vifor was the group’s clear growth segment over the period, with the company pointing to nephrology as the main driver. 

Vifor’s original identity was strongly tied to iron deficiency, and that part of the business is now under pressure. CSL said iron sales declined because of generic competition in Europe and the U.S., while its presentation showed the broader iron category down 15%. That makes the future of Vifor less dependent on defending its legacy iron franchise and more dependent on whether CSL can build momentum in nephrology and cardio-renal disease. 

The stronger signs are coming from those newer areas. Dialysis nephrology revenue rose 40% to $544 million, helped by Velphoro’s inclusion in the U.S. Transitional Drug Add-on Payment Adjustment program. Non-dialysis nephrology revenue rose 45% to $191 million, supported by continued uptake of Tavneos and launches of Filspari in Europe and other markets. 

CSL’s recent deals show a more selective business development strategyBack to Top

CSL’s recent deals suggest it is still looking outside for new science, but it is doing so through option agreements, collaborations, and selective licensing rather than another large acquisition like Vifor. 

In September 2025, CSL agreed to pay $117 million upfront for an exclusive option to acquire the Dutch biotech, VarmX after phase 3 data for VMX-C001, an investigational therapy designed to restore coagulation in patients who need urgent surgery or experience severe bleeding while taking Factor Xa anticoagulants. If the option is exercised and certain milestones are met, VarmX could receive up to $388 million up to launch, with commercial launch anticipated in 2029. 

Strategically, this is close to CSL’s historical strengths. VMX-C001 sits in coagulation and emergency bleeding, a field adjacent to CSL’s hemophilia and perioperative bleeding businesses. Additionally, the option structure gives CSL a way to secure access to a late-stage asset without committing immediately to a full acquisition before phase 3 data are available. 

In February 2026, CSL also entered a collaboration and option agreement around Memo Therapeutics’ recombinant polyclonal IgG technology. Memo will develop products using its DROPZYLLA platform for cloning human antibody repertoires and polyclonal antibody expression, while CSL receives an option to exclusively license the resulting products. 

The clazakizumab agreement with Eli Lilly shows another dimension of the same strategy. Instead of trying to develop the therapy for every possible indication by itself, CSL licensed rights to Lilly to explore clazakizumab outside end-stage kidney disease. CSL retained exclusive rights to develop and commercialize the antibody for preventing cardiovascular events in patients with end-stage kidney disease, while Lilly paid $100 million upfront and may provide additional milestones and royalties. 

Innovation close to the core Back to Top

CSL’s recent product launches look similar to its dealmaking. The company is not trying to redefine itself around an entirely new therapeutic identity. Instead, its newer products mostly sit close to areas where CSL already has scientific, manufacturing, or commercial experience. 

ANDEMBRY was approved by the U.S Food and Drug Administration (FDA) in June 2025. The drug is a prophylactic treatment for hereditary angioedema that targets factor XIIa, a protein involved near the top of the HAE cascade. CSL already had a long-standing HAE franchise, but ANDEMBRY gives it a newer antibody-based product with once-monthly dosing. In the VANGUARD trial, the treatment reduced HAE attacks by a median of more than 99% compared with placebo. 

HEMGENIX shows the same logic in hematology, as the hemophilia B gene therapy is very different from CSL’s traditional plasma-derived and recombinant clotting factor products, but it still fits within the company’s historical expertise in bleeding disorders.  

ANDEMBRY strengthens a rare disease franchise that CSL already understands, while HEMGENIX adds an advanced modality to a hematology business where the company has long-standing relationships and infrastructure. 

The company is not becoming a different kind of biotech; it is trying to become a more focused version of the one it already is. Plasma, immunoglobulins, rare diseases and complex biologics remain central to the business, but CSL is now trimming the structure around them: separating vaccines when conditions allow, integrating Vifor more tightly, reducing duplication, and using partnerships or option-based deals to bring in innovation without adding another layer of complexity.