Zanidatamab

- Exploratory analysis from Phase 1b/2 breast cancer trial reinforces CD47 as a predictive biomarker for response, as previously observed in the ASPEN-06 trial in HER2-positive gastric cancer – - Full data set submitted for presentation at an upcoming scientific conference - SOUTH SAN FRANCISCO, Calif., Jan. 30, 2026 (GLOBE NEWSWIRE) -- ALX Oncology Holdings Inc. (“ALX Oncology,” Nasdaq: ALXO), a clinical-stage biotechnology company advancing a pipeline of novel therapies designed to treat cancer and extend patients’ lives, announced new data from a Phase 1b/2 clinical trial evaluating the company’s investigational CD47-inhibitor evorpacept in combination with Jazz Pharmaceuticals’ ZIIHERA® (zanidatamab-hrii) in heavily pretreated patients with metastatic breast cancer (mBC). The topline findings, from an exploratory analysis in this trial, indicate that among patients with confirmed HER2-positive mBC, CD47 expression is predictive of evorpacept activity. “These new findings support a CD47-dependent, HER2-driven biology for evorpacept,” said Barbara Klencke, M.D., Chief Medical Officer at ALX Oncology. “Going forward, we believe that a biomarker-driven approach incorporating CD47 expression may optimize patient selection for evorpacept combinations with HER2-targeted agents. Additionally, taken together, the data from this trial and the ASPEN-06 clinical trial reinforce our confidence in the ongoing ASPEN-09-Breast Phase 2 trial.” The Phase 1b/2 open-label, multi-center clinical trial (NCT05027139) evaluated the potential of evorpacept in combination with zanidatamab as a novel treatment for patients with previously treated, inoperable, locally advanced, or metastatic HER2-expressing breast cancer and other cancers. The primary trial results, presented at the 2024 San Antonio Breast Cancer Symposium (SABCS), demonstrated that the investigational combination generated promising anti-tumor activity and a manageable safety profile in patients with heavily pretreated HER2-positive breast cancer (median of six prior therapies), including treatment with ENHERTU. Researchers previously reported a 56% (5/9) confirmed objective response rate (cORR) and a median progression-free survival (mPFS) of 7.4 months in the nine patients with centrally confirmed HER2-positive breast cancer who received the investigational combination. The additional exploratory analysis, conducted to identify biomarkers of response to the evorpacept/zanidatamab combination, shows that responses in this trial were largely restricted to patients with higher CD47 expression. This finding reinforces results from the ASPEN-06 clinical trial, which demonstrated that CD47 expression is a predictive biomarker for response and durable benefit from evorpacept among patients with advanced gastric cancer that has retained HER2 expression. The full biomarker analysis from the Phase 1b/2 clinical trial has been submitted to an upcoming scientific congress for presentation. About ALX Oncology ALX Oncology (Nasdaq: ALXO) is a clinical-stage biotechnology company advancing a pipeline of novel therapies designed to treat cancer and extend patients’ lives. ALX Oncology’s lead therapeutic candidate, evorpacept, has demonstrated potential to serve as a cornerstone therapy upon which the future of immuno-oncology can be built. Evorpacept is currently being evaluated across multiple ongoing clinical trials in a wide range of cancer indications. ALX Oncology’s second pipeline candidate, ALX2004, is a novel EGFR-targeted antibody-drug conjugate with a differentiated mechanism of action. A Phase 1, dose-escalation trial of ALX2004 is ongoing in patients with EGFR-expressing solid tumors. More information is available at www.alxoncology.com and on LinkedIn @ALX Oncology. Cautionary Note Regarding Forward-Looking Statements This press release contains forward-looking statements that involve substantial risks and uncertainties. Forward-looking statements include statements regarding future results of operations and financial position, business strategy, product candidates, planned preclinical studies and clinical trials, results of clinical trials, research and development costs, regulatory approvals, timing and likelihood of success, plans and objects of management for future operations, as well as statements regarding industry trends. Such forward-looking statements are based on ALX Oncology’s beliefs and assumptions and on information currently available to it on the date of this press release. Forward-looking statements may involve known and unknown risks, uncertainties and other factors that may cause ALX Oncology’s actual results, performance or achievements to be materially different from those expressed or implied by the forward-looking statements. These and other risks are described more fully in ALX Oncology’s filings with the Securities and Exchange Commission (SEC), including ALX Oncology’s Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and other documents ALX Oncology files with the SEC from time to time. Except to the extent required by law, ALX Oncology undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made. Investor Relations Contact: Elhan Webb, CFA, IR Consultant ewebb@alxoncology.com Media Contact: Michele Parisi, SparkPoint Healthcare Communications mparisi@sparkpointpr.com (925) 864-5028

Phase 1b study to evaluate combination of zongertinib and zanidatamab in HER2-positive breast cancer patients Ingelheim, Germany– 12 January, 2026 – Boehringer Ingelheim today announced a strategic clinical collaboration with Jazz Pharmaceuticals (Nasdaq: JAZZ) on the exploration of a novel combination therapy for patients with HER2-positive breast cancer. As part of this collaboration, the partners will initiate a Phase 1b cohort within Boehringer’s ongoing Beamion-BCGC1 trial, evaluating the combination of Boehringer’s zongertinib and Jazz’s zanidatamab in breast cancer. Despite significant progress in HER2-targeted therapies, HER2-positive breast cancer remains an aggressive subtype, accounting for approximately 15–20% of all breast cancers. Advanced or metastatic patients still have poor five-year survival rates, around 50%. This collaboration aims to improve patient outcomes by combining two differentiated HER2-targeted approaches, potentially offering a new therapeutic option for patients. “At Boehringer Ingelheim, we are committed to pushing the boundaries of science to deliver innovative solutions for patients with high unmet need,” said Itziar Canamasas, Global Head of Oncology at Boehringer Ingelheim. “By combining zongertinib’s precision approach with zanidatamab’s unique bispecific antibody mechanism, we aim to unlock new possibilities for patients living with HER2-expressing breast cancer.” Amal Melhem-Bertrandt, VP, Oncology Therapy Area Head and Zanidatamab Global Clinical Lead at Jazz Pharmaceuticals., said, “This research collaboration with Boehringer Ingelheim is centered in our shared vision to transform treatment paradigms in HER2-expressing breast cancer through the investigation of this novel HER2-targeted combination therapy, as well as possible opportunities to advance outcomes in multiple tumor types.” HERNEXEOS® (zongertinib tablets) recently received FDA (accelerated) approval in the U.S., CDE (conditional) approval in China, and PMDA marketing authorization in Japan as the first orally administered, targeted therapy for previously treated patients with HER2 (ERBB2)-mutant advanced non-small cell lung cancer (NSCLC). In the Beamion LUNG-1 trial, zongertinib demonstrated an objective response rate (ORR) of 71% specifically in pre-treated patients with HER2-mutant NSCLC, along with durable responses. Zongertinib is also under investigation in ongoing clinical trials for various HER2-driven tumors. ZIIHERA® (zanidatamab), a bispecific HER2-directed antibody, has received accelerated approval from the U.S. FDA for the treatment of adults with previously treated, unresectable or metastatic HER2-positive (IHC 3+) biliary tract cancer. Further, it is currently in Phase III trials for GEA, BTC and metastatic breast cancer, and is also being investigated in earlier lines of therapy in other tumor types. The companies anticipate that this study will generate critical insights into the safety and efficacy of dual HER2 blockade and inform the development of a potential future combination therapy. Boehringer Ingelheim Boehringer Ingelheim is a biopharmaceutical company active in both human and animal health. As one of the industry’s top investors in research and development, the company focuses on developing innovative therapies that can improve and extend lives in areas of high unmet medical need. Independent since its foundation in 1885, Boehringer takes a long-term perspective, embedding sustainability along the entire value chain. Our approximately 54,500 employees serve over 130 markets to build a healthier and more sustainable tomorrow. Learn more at . Intended Audiences Notice This press release is issued from our Corporate Headquarters in Ingelheim, Germany and is intended to provide information about our global business. Please be aware that information relating to the approval status and labels of approved products may vary from country to country, and a country-specific press release on this topic may have been issued in the countries where we do business.