HER2-Positive Breast Cancer | Market Size, Share & Growth Report 2024-2029

North America carries the largest disclosed revenue and the clearest measured growth in this market. Enhertu in-market sales in the United States rose to USD 2,446 million in FY2025 from USD 1,864 million in FY2024, an increase of about 31%, and that single country accounted for roughly half of the product's worldwide growth over the period. That is a regional revenue figure rather than an attributed share, which distinguishes this market from most others in this series. The region also sets the pace on indication expansion, since approvals here typically precede those elsewhere and determine how quickly HER2-low and early-stage populations become treatable. The concentration is commercial rather than epidemiological: HER2-positive disease accounts for a similar share of breast cancers worldwide, so the regional lead reflects pricing and access rather than a larger patient population.

Europe is where biosimilar competition has advanced furthest and where the franchise economics are therefore changing fastest. Herceptin sales continue to decline on biosimilar erosion, and because trastuzumab is the backbone that pertuzumab and the conjugates are added to, cheaper trastuzumab lowers the cost of the combination regimens rather than displacing them. The region's commercial position is best described as a mature market converting from originator to biosimilar backbone while adopting the newer conjugates on top. No Europe-specific market size or growth figure was identified among the sources examined, because both franchise owners report HER2 results globally or split only the United States from an international aggregate.

Asia Pacific supplies both a manufacturer and the clearest growth signal outside the United States. Phesgo sales rose 48% to CHF 2.4 billion in 2025, and that growth was reported across all regions but primarily in the International segment and particularly in China, where conversion from the older presentations is running fastest. Japan is significant separately, both as the home of one of the two companies recording Enhertu sales and as a regulator moving early on indication expansion. Its Ministry of Health, Labour and Welfare approved the conjugate in August 2025 for hormone receptor-positive, HER2-low or HER2-ultralow metastatic disease after endocrine therapy. No Asia Pacific market size figure was identified, since the 48% figure is a worldwide product growth rate that the company attributes primarily to the region rather than a measured regional total.

No market size, revenue or growth figure specific to Latin America was identified, and neither franchise owner reports results for the region separately from a wider international aggregate. The structural position is that biosimilar trastuzumab is the practical entry point for HER2-directed treatment in cost-constrained health systems, because it makes the backbone affordable, while the pertuzumab combinations and antibody-drug conjugates that carry most of the value elsewhere remain substantially more expensive. Access in the region is therefore likely to be sequenced rather than simultaneous, with the originator-era regimens reaching patients well before the conjugates. Nothing in the evidence examined quantifies how far that sequence has progressed.

No market size, revenue, access or prescribing figure specific to the Middle East and Africa was identified for HER2-positive breast cancer, and no company examined discloses activity there separately. The determining factor for this region is diagnostic rather than therapeutic: HER2 status must be established by immunohistochemistry or in situ hybridisation before any of these agents can be used, so pathology capacity governs how many patients are eligible. Where HER2 testing is not routinely available, patients are treated as though they have HER2-negative disease regardless of biology, which removes them from this market entirely. That constraint operates before price or supply becomes relevant.