Sirtex Medical earns FDA nod for SIR-Spheres® Y-90 in treating unresectable liver cancer in U.S.

Why has Sirtex Medical received FDA approval for its SIR-Spheres® Y-90 treatment for unresectable liver cancer in 2025?

Sirtex Medical Inc., a global manufacturer of interventional oncology solutions, secured a major regulatory milestone on July 7, 2025, with the U.S. Food and Drug Administration’s approval of its SIR-Spheres® Y-90 resin microspheres for the treatment of unresectable hepatocellular carcinoma (HCC). This makes SIR-Spheres® the only radioembolization therapy approved in the United States for both HCC and metastatic colorectal cancer (mCRC) of the liver. With this expanded indication, the Australian-origin medical device developer strengthens its foothold in the U.S. oncology market at a time when liver cancer remains among the most fatal malignancies in adults.

Radioembolization, formally referred to as selective internal radiation therapy (SIRT), delivers targeted radiation via resin microspheres. SIR-Spheres® utilize Yttrium-90 (Y-90), a beta-emitting isotope, to achieve localized cytotoxic effects while preserving adjacent healthy tissue. This latest regulatory development enables oncologists to offer a personalized, minimally invasive therapy for a liver cancer population with few surgical options.

According to the American Cancer Society, hepatocellular carcinoma accounts for the vast majority of primary liver cancers in the United States. Many patients present with tumors considered inoperable due to size, location, or liver function complications. Sirtex Medical’s SIR-Spheres® technology addresses this gap, offering a precision-dosed, liver-directed alternative that aligns with multidisciplinary care models.

How did the DOORwaY90 clinical trial contribute to the FDA’s decision to expand approval for SIR-Spheres® Y-90 in liver cancer?

The FDA’s approval was largely underpinned by compelling efficacy and safety data from the DOORwaY90 clinical trial, a multicenter, open-label study designed to evaluate the impact of SIR-Spheres® Y-90 in patients with unresectable HCC. Conducted across 18 leading oncology institutions in the U.S., the trial enrolled 100 patients, with 65 included in the interim primary efficacy cohort. The trial achieved both prespecified co-primary endpoints, delivering a best overall response rate (ORR) of 98.5%, as confirmed by independent central review.

All evaluable participants demonstrated a measurable tumor response, resulting in a 100% local tumor control rate. Furthermore, the median duration of response (DoR) exceeded 300 days, indicating prolonged benefit from the intervention. The trial also affirmed the reproducibility of the dosimetry models used in SIR-Spheres®, supporting scalable deployment in clinical settings.

DOORwaY90’s success was bolstered by a favorable safety profile, a critical consideration for therapies targeting compromised hepatic function. “This study moves the field of radioembolization forward with reproducible dosimetry outcomes and a strong safety profile linked to very positive clinical results,” said Dr. Armeen Mahvash, Interventional Radiologist at MD Anderson Cancer Center and a Co-Principal Investigator in the study.

Institutional sentiment suggests that the trial’s rigor and multicenter structure will drive broader oncologist adoption, particularly among those seeking non-surgical yet curative-intent interventions. The results are expected to serve as a cornerstone for further global regulatory filings and post-approval studies in Asia-Pacific and Europe.

What makes SIR-Spheres® Y-90 a differentiated option in the liver-directed therapy landscape in oncology?

SIR-Spheres® Y-90 resin microspheres stand out for their dual indication—HCC and mCRC—which no other radioembolization therapy currently claims in the U.S. market. While systemic chemotherapy and immunotherapy have been the mainstay for advanced liver cancers, SIR-Spheres® offer locoregional tumor control through personalized dosimetry, delivering an optimized dose of radiation directly to liver tumors.

Patients eligible for SIR-Spheres® must have no macrovascular invasion, well-compensated liver function (Child-Pugh A), and good overall performance status. The therapy is also indicated for unresectable metastatic liver tumors originating from primary colorectal cancer, in conjunction with intrahepatic artery chemotherapy (IHAC) of Floxuridine (FUDR).

Sirtex Medical’s daily delivery model—offering multiple dose options—further enhances treatment accessibility for busy oncology centers. As a device-based approach, SIR-Spheres® also complement systemic regimens, enabling their integration into combination therapy strategies, particularly in multidisciplinary tumor boards.

Analysts view the expanded indication as a commercial accelerant that could reshape standard-of-care frameworks in tertiary oncology centers, particularly for patients contraindicated for systemic agents or surgery. With over 120,000 new cases of liver and intrahepatic bile duct cancer diagnosed annually in the U.S., the addressable market potential is significant.

How is the U.S. interventional oncology market expected to respond to Sirtex Medical’s expanded regulatory approval?

Institutional investors and oncology market watchers have responded positively to the FDA approval, citing enhanced reimbursement potential and greater formulary inclusion across U.S. hospitals. Although Sirtex Medical is privately held and does not trade on public exchanges, industry insiders expect the regulatory milestone to bolster its valuation in any future acquisition or IPO scenarios.

The American medical devices sector has seen increasing demand for minimally invasive, precision-dosed therapies that can be administered in outpatient settings. SIR-Spheres® fit squarely into this trend, offering interventional radiologists a scalable, low-toxicity solution for patients with complex hepatic tumors.

Additionally, the FDA’s decision is likely to influence payer coverage decisions, particularly in light of the DOORwaY90 data that demonstrate high efficacy and manageable safety. Analysts anticipate a wave of formulary reviews in the second half of 2025, with academic centers and large oncology networks at the forefront of adoption.

Multinational competitors in the embolization and radiopharmaceutical space may also see this as a trigger to fast-track their own pipeline strategies, especially in Europe and Japan where Sirtex Medical has a well-established footprint.

What is the future outlook for Sirtex Medical’s oncology platform following this FDA approval?

Looking forward, Sirtex Medical is expected to pursue label expansion strategies in other geographies, including regulatory submissions in Canada, Brazil, and select Asian markets. The company’s focus on advancing liver-directed therapies may also open pathways to combination trials with checkpoint inhibitors or targeted agents, especially in intermediate-stage HCC.

In terms of pipeline development, institutional stakeholders expect Sirtex Medical to invest further in companion imaging technologies and real-time dosimetry tools to enhance procedural precision. The FDA approval of SIR-Spheres® Y-90 in HCC is likely to act as a springboard for deeper clinical integration and broader reimbursement support.

Clinical opinion leaders are also advocating for updates to national treatment guidelines, particularly those issued by the NCCN and EASL, to include SIR-Spheres® as a frontline locoregional option for well-selected HCC patients.

Analysts believe the expanded FDA approval will improve Sirtex Medical’s bargaining position in strategic collaborations, technology licensing, or potential buyout discussions, especially with large-cap oncology-focused medical device manufacturers.