Citius Oncology Reports Strong Commercial Momentum for its Cancer Treatment

New institutional accounts ordering LYMPHIR increased 78% quarter over quarter

LYMPHIR's near-universal payer coverage expands market access

Initial cutaneous T-cell lymphoma (CTCL) market for LYMPHIR currently exceeds $400 million

CRANFORD, N.J., Aug. 5, 2026 /PRNewswire/ -- Citius Oncology, Inc. ("Citius Oncology") (Nasdaq: CTOR), an oncology‑focused biopharmaceutical company and majority‑owned subsidiary of Citius Pharmaceuticals, Inc. ("Citius Pharma") (Nasdaq: CTXR), today provided an update on the expanding base of institutions ordering LYMPHIR® (denileukin diftitox-cxdl) through wholesalers, continued formulary progress at priority U.S. treatment centers, and other key indicators supporting the product's commercial launch.

"Our commercial progress is reflected in two closely connected measures: growth in the number of institutions ordering LYMPHIR and continued expansion of the formulary approvals that enable additional institutions to begin ordering the product and treating patients," said Leonard Mazur, Chairman and Chief Executive Officer of Citius Oncology. "I am pleased to report that the number of new institutions ordering LYMPHIR rose, total institutional vial orders increased, formulary reviews and approvals grew, and wholesalers are reordering LYMPHIR to reflect this growth. Formulary inclusion is a key gateway to institutional ordering and patient access. The success of our targeted launch, so far, was accomplished by a small yet focused internal launch team. Together with our recently expanded commercial and medical affairs teams, we believe Citius Oncology is well positioned to broaden engagement with over 250 priority treatment centers, support continued adoption, and accelerate topline growth through the balance of the year."

LYMPHIR is now available in 42 institutions including academic oncology centers, leading National Comprehensive Cancer Network (NCCN) institutions and community infusion centers. During the quarter ended June 30, 2026, the number of new institutions increased 78% compared with the prior quarter. Vials ordered by institutions from wholesalers rose 31% during the quarter. Subsequent to the quarter ended June 30, 2026, following an increase in both the number of ordering institutions and vial demand, orders from wholesalers have begun to reflect this incremental demand. Citius revenue is recognized when wholesale orders for LYMPHIR are placed and filled.

LYMPHIR's growing institutional footprint consists of leading academic and cancer treatment centers with recognized CTCL expertise. Formulary inclusion is an important step in the commercial adoption process. Once approved, an institution can order the product through a nationwide wholesaler network and make the therapy available for prescribing to eligible adult patients with relapsed or refractory cutaneous T-cell lymphoma (CTCL). Review times vary by institution and may range from several weeks to several months. Based on Company experience to date, institutions that add LYMPHIR to formulary have generally placed their first patient order within approximately two to six weeks. Citius Oncology anticipates more than 20 additional institutions during the current quarter, and is targeting formulary inclusion with 100 priority institutions by year-end.

The Company continues to engage leading CTCL experts through scientific exchange and educational initiatives designed to increase understanding of LYMPHIR's clinical profile and support institutional evaluation of the therapy. At the Sixth World Congress of Cutaneous Lymphomas in Montreal, the Company met with many U.S. and international CTCL key opinion leaders. The expanded medical affairs team is expected to increase the frequency and breadth of the Company's scientific engagement with the CTCL community.

According to Company tracking, LYMPHIR has secured near-universal payer coverage. Formulary inclusion and payer coverage address complementary requirements for market access. Together, these indicators reflect continued progress in building LYMPHIR's commercial foundation.

About LYMPHIR™ (denileukin diftitox‑cxdl)

LYMPHIR is a targeted immune therapy for relapsed or refractory cutaneous T-cell lymphoma (CTCL) indicated for use in Stage I-III disease after at least one prior systemic therapy. It is a recombinant fusion protein that combines the IL-2 receptor binding domain with diphtheria toxin (DT) fragments. The agent specifically binds to IL-2 receptors on the cell surface, causing diphtheria toxin fragments that have entered cells to inhibit protein synthesis. After uptake into the cell, the DT fragment is cleaved and the free DT fragments inhibit protein synthesis, resulting in cell death. Denileukin diftitox-cxdl demonstrated the ability to deplete immunosuppressive regulatory T lymphocytes (Tregs) and antitumor activity through a direct cytocidal action on IL-2R-expressing tumors.

In 2021, reformulated denileukin diftitox received regulatory approval in Japan for the treatment of relapsed or refractory CTCL and peripheral T-cell lymphoma (PTCL). Subsequently, in 2021, Citius acquired an exclusive license with rights to develop and commercialize reformulated denileukin diftitox in all markets except for India, Japan and certain parts of Asia. LYMPHIR (denileukin diftitox-cxdl) was approved by the FDA and subsequently launched in the U.S. in December 2025.

About Citius Oncology, Inc.

Citius Oncology, Inc. (Nasdaq: CTOR) is a platform to develop and commercialize novel targeted oncology therapies. In December 2025, Citius Oncology launched LYMPHIR, approved by the FDA for the treatment of adults with relapsed or refractory Stage I–III CTCL who had had at least one prior systemic therapy. Management estimates the initial CTCL market for LYMPHIR currently exceeds $400 million, is growing, and is underserved by existing therapies. Robust intellectual property protections that span orphan drug designation, complex technology, trade secrets and pending patents for immuno-oncology use as a combination therapy with checkpoint inhibitors would further support Citius Oncology's competitive positioning. For more information, please visit www.citiusonc.com.

Forward-Looking Statements

This press release may contain "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Such statements are made based on our expectations and beliefs concerning future events impacting Citius Oncology. You can identify these statements by the fact that they use words such as "will," "anticipate," "estimate," "expect," "plan," "should," and "may" and other words and terms of similar meaning or use of future dates. Forward-looking statements are based on management's current expectations and are subject to risks and uncertainties that could negatively affect our business, operating results, financial condition and stock price. Factors that could cause actual results to differ materially from those currently anticipated are: our ability to successfully commercialize LYMPHIR and establish a sustainable revenue stream; the estimated markets for LYMPHIR and our product candidates and the acceptance thereof by any market; our ability to use the latest technology to support our commercialization efforts for LYMPHIR; physician and patient acceptance of LYMPHIR in a competitive treatment landscape; our ability to raise additional money to fund our operations; our ability to regain compliance with Nasdaq's continued listing standards; our ability to obtain, perform under and maintain third party agreements and relationships, including obtaining a new bulk drug substance supplier; risks relating to the results of research and development activities, including those from our existing and any new pipeline assets; early-stage clinical data may not be predictive of results from larger or later-stage studies; our ability to secure and maintain strategic partnerships and expand international access to LYMPHIR; our reliance on third-party logistics providers, distributors, and specialty pharmacies to support commercial operations; our ability to educate providers and payers, secure adequate reimbursement, and maintain uninterrupted product supply; post-marketing requirements and ongoing regulatory compliance related to LYMPHIR; the ability of LYMPHIR and our product candidates to impact the quality of life of our target patient populations; our ability to procure cGMP commercial-scale supply; risks related to our growth strategy; patent and intellectual property matters; government regulation; as well as other risks described in our Securities and Exchange Commission ("SEC") filings. Accordingly, these forward-looking statements do not constitute guarantees of future performance, and you are cautioned not to place undue reliance on these forward-looking statements. Risks regarding our business are described in detail in our SEC filings which are available on the SEC's website at www.sec.gov, including in Citius Oncology's Annual Report on Form 10-K for the year ended September 30, 2025, filed with the SEC on December 23, 2025. These forward-looking statements speak only as of the date hereof, and we expressly disclaim any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in our expectations or any changes in events, conditions or circumstances on which any such statement is based, except as required by law.

LYMPHIR (denileukin diftitox‑cxdl)

INDICATION

LYMPHIR is an IL2-receptor-directed cytotoxin indicated for the treatment of adult patients with r/r Stage I-III cutaneous T-cell lymphoma (CTCL) after at least one prior systemic therapy.

IMPORTANT SAFETY INFORMATION

BOXED WARNING: CAPILLARY LEAK SYNDROME

Capillary leak syndrome (CLS), including life-threatening or fatal reactions, can occur in patients receiving LYMPHIR. Monitor patients for signs and symptoms of CLS during treatment. Withhold LYMPHIR until CLS resolves, or permanently discontinue based on severity.

WARNINGS AND PRECAUTIONS

Capillary Leak Syndrome

LYMPHIR can cause capillary leak syndrome (CLS), including life-threatening or fatal reactions. CLS was defined in the clinical trials as the occurrence of at least 2 of the following symptoms at any time during LYMPHIR therapy: hypotension, edema, and serum albumin ...