ALX Oncology's CD47 Biomarker Data Bolsters HER2-Positive Treatment Pipeline Amid Biotech Momentum

On May 9, 2026, ALX Oncology Holdings Inc. (NASDAQ: ALXO) reported promising interim data from the ASPEN-09 Phase 2/3 trial, underscoring the role of CD47 expression as a predictive biomarker for enhanced clinical responses in heavily pretreated HER2-positive gastric cancer patients. The data, derived from approximately 80 patients, revealed that those with high CD47 expression experienced significantly more durable responses when treated with evorpacept, the company's CD47-blocking therapeutic candidate, in combination with standard HER2-targeted therapies. This development not only validates ALX's CD47-selection hypothesis but also positions evorpacept as a potentially transformative agent in a segment where treatment options remain limited.

Key Trial Findings and Clinical Implications

The ASPEN-09 trial evaluates evorpacept combined with trastuzumab deruxtecan (Enhertu) versus Enhertu alone in patients with advanced HER2-positive gastric cancer who have progressed after at least one prior line of therapy. Interim results, as outlined in ALX's first-quarter 2026 financial results and corporate update released on May 9, demonstrated that CD47-high patients achieved deeper and more sustained responses. Specifically, CEO and Director Jason Hoover noted that "CD47 expression is a key predictive biomarker for increasing durable clinical response in heavily pretreated HER2-positive patients." This biomarker-driven approach could enable patient stratification, improving trial success rates and accelerating regulatory pathways.

Complementing these findings, data from two independent HER2-positive trials further reinforce the hypothesis. In the ASPEN-02 trial, evorpacept plus trastuzumab, ramucirumab, and paclitaxel showed a 65% objective response rate (ORR) in CD47-high patients compared to historical benchmarks. Similarly, ASPEN-03 results indicated prolonged progression-free survival (PFS) in frontline HER2-positive gastric cancer settings. These outcomes suggest evorpacept's mechanism—blocking the CD47 'don't eat me' signal on cancer cells to enhance macrophage-mediated phagocytosis—synergizes effectively with antibody-drug conjugates and other HER2 agents, potentially expanding its utility beyond gastric cancer to breast and other HER2-driven malignancies.

Financial Snapshot and Market Reaction

ALX Oncology's Q1 2026 financials reflect a company lean and focused on high-impact clinical milestones. Cash reserves stood at approximately $150 million as of March 31, 2026, providing runway into late 2027 without immediate dilution risks. Research and development expenses totaled $25.4 million for the quarter, driven by ongoing trials, while general and administrative costs were controlled at $6.2 million. Revenues remained nominal at $0.3 million from collaborations, underscoring ALX's clinical-stage profile.

Market response was swift and bullish. ALXO shares surged over 20% in pre-market trading on May 9, closing the day up 15.3% at $2.45, on volume exceeding 5 million shares—more than triple the average. This move aligns with broader biotech sentiment, where positive oncology readouts often catalyze sector-wide gains. The iShares Biotechnology ETF (IBB) rose 1.2% on the same day, buoyed by ALX's news amid a stable macroeconomic backdrop.

Impact on Biotech and Pharma Pipelines

ALX's data arrives at a pivotal moment for the biotechnology sector, where biomarker-stratified trials are increasingly viewed as a derisking strategy. The CD47 pathway has faced hurdles historically, with earlier candidates like magrolimab from Gilead Sciences encountering safety issues in broad populations. ALX's targeted approach mitigates these risks, potentially setting a new standard for CD47 inhibitors. For pharma partners, this enhances the attractiveness of evorpacept; ALX's collaboration with Zymeworks on similar HER2 combinations could lead to expanded deals.

In the HER2-positive landscape, dominated by Roche's Herceptin and Daiichi Sankyo/AstraZeneca's Enhertu—which generated $2.9 billion in 2025 sales—evorpacept offers differentiation through immune modulation. By improving response durability in later lines, it could capture a slice of the $10 billion-plus annual HER2 market. Broader implications extend to combo regimens: preclinical data suggest synergies with PD-1 inhibitors, opening doors in immuno-oncology pipelines for companies like Merck and Bristol Myers Squibb.

Regulatory Environment and Path Forward

The U.S. FDA's emphasis on precision medicine favors ALX's biomarker strategy. Recent approvals, such as those for tumor-agnostic therapies like Keytruda based on MSI-high status, illustrate regulators' willingness to endorse stratified indications. ALX plans to initiate a Phase 3 trial in CD47-high HER2-positive gastric cancer by year-end 2026, with potential accelerated approval filings in 2028 based on PFS endpoints. European Medicines Agency alignment could follow, given harmonized oncology guidelines.

Risks persist: full ASPEN-09 readout expected H2 2026 could temper enthusiasm if overall survival benefits underwhelm in the intent-to-treat population. Nonetheless, the CD47-high subset's robust signal derisks the program, potentially attracting buyout interest from big pharma seeking late-stage assets. Comparable deals, like Gilead's $4.9 billion Forty Seven acquisition in 2020, highlight the premium on validated CD47 platforms.

Biotech Stock Outlook and Sector Context

ALXO's valuation at $120 million market cap implies significant upside. Analysts project peak sales of $800 million for evorpacept in gastric cancer alone, with enterprise value multiples in oncology biotech averaging 5-7x peak sales. Consensus price targets cluster around $8-12, suggesting 200-400% appreciation if milestones hit.

Sector-wide, this news reinforces biotech's resilience. Despite 2025's volatility—IBB down 8% YTD through April 2026—oncology remains a bright spot, with M&A activity up 25% year-over-year per Evaluate Pharma. Peers like MacroGenics (MGNX) and Sutro Biopharma (STRO), also in HER2 space, saw sympathetic gains of 5-8% on May 9. Investors should monitor upcoming catalysts: ALX's ASPEN-06 breast cancer data in Q3 2026 and potential partnership announcements.

Strategic Considerations for Investors

For institutional portfolios, ALX exemplifies high-conviction biotech plays: strong cash position, clean data, and a clear regulatory line-of-sight. Pairing with diversified ETFs like XBI mitigates single-stock risk while capturing upside. In a slightly bullish macro environment—with Fed funds at 4.25-4.5% and biotech funding rebounding—such readouts could propel a sector rally into summer.

Challenges include competition from next-gen HER2 therapies and execution risks in Phase 3. Yet, the biomarker validation tilts odds favorably, making ALX a watchlist staple. As CD47 moves from promise to proof, ALX Oncology stands poised to redefine HER2 treatment paradigms.

In summary, these results not only advance ALX's pipeline but signal a maturing era for immune-checkpoint innovation in solid tumors, fostering optimism across biotech equities.