New Preclinical Results at AACR 2026 Show Plinabulin Dramatically Improves Complete Response Rates and Survival When Combined with Leading ADC Drugs — With or Without Immunotherapy

Plinabulin's GEF-H1 Agonist Mechanism Drives Synergistic Antitumor Activity And CIN Mitigation Across TOP1-ADC ± PD-1/PD-L1 Inhibitor Regimens in Preclinical Models

FLORHAM PARK, N.J., April 22, 2026 (GLOBE NEWSWIRE) -- BeyondSpring Inc. (NASDAQ:BYSI) today reported new preclinical data at the 2026 Annual Meeting of the American Association for Cancer Research (AACR) demonstrating that Plinabulin has the potential to enhance both the efficacy and tolerability of ADC therapy — potentially boosting anticancer responses while keeping patients on treatment long enough to benefit.

Antibody-drug conjugates — a form of targeted chemotherapy that delivers cancer-killing agents directly to tumor cells, known as ADCs — have emerged as one of oncology's most important new treatment classes. But two persistent clinical barriers limit their full potential: they do not always produce durable responses, and neutropenia (a dangerous drop in white blood cell counts) can force dose reductions or treatment delays that cut treatment short. New AACR data show that Plinabulin directly and simultaneously addresses both.

Three Key Findings from AACR 2026

The data show why the combination works. Plinabulin, when added to two leading approved ADCs — T-DXd (trastuzumab deruxtecan) and Dato-DXd (datopotamab deruxtecan) — produced three significant results that neither drug achieved alone:

Stronger anticancer activity: Complete tumor regressions were more frequent and animals survived significantly longer — in both two-drug (ADC+ Plinabulin) and three-drug (ADC+ Plinabulin + PD-1 inhibitor) combinations (PD-1 inhibitors are immunotherapies that activate the body's own immune system to fight cancer).
Better tolerability to potentially keep patients on therapy: Plinabulin reduced animal death in both two-drug and three-drug combinations. In 6 prior clinical studies, Plinabulin measurably reduced chemotherapy-induced neutropenia, the white blood cell toxicity that commonly forces ADC dose reductions or treatment delays — potentially allowing patients to remain on treatment long enough to benefit from the drug's anticancer activity.
Immune system activation: Analysis showed that Plinabulin enhanced the body's own cancer-fighting T-cells, significantly increasing CD8+ T cell/Treg ratio — providing a biological explanation for why the combination outperforms either drug alone.

Plinabulin is Mechanistically Complementary, Not Merely Additive

Plinabulin activates a protein called GEF-H1 that simultaneously matures immune cells (dendritic cells) to attack tumors, signals the body to replenish cancer-fighting blood cells, and disrupts the blood supply feeding tumors. These are precisely the biological pathways that ADCs do not activate — which is why the two work better together than either does alone.

In BeyondSpring's pivotal Phase 3 DUBLIN-3 study (The Lancet Respiratory Medicine, 2024), Plinabulin combined with docetaxel chemotherapy doubled two- and three-year survival rates in second- and third-line EGFR wild-type NSCLC patients — and simultaneously reduced docetaxel-limiting grade 4 neutropenia from 33% to 5%, keeping patients on therapy longer for the drug to work. The new AACR data extend that same combination logic into the ADC setting, broadening Plinabulin's reach across the treatment landscape.

BeyondSpring's planned DUBLIN-4 program — a 442-patient FDA-aligned confirmatory Phase 3 trial building directly on the DUBLIN-3 results — is the defined next clinical step. Today's AACR data further strengthen the scientific rationale for Plinabulin's combination potential and point toward future ADC combination studies beyond the confirmatory program.

Plinabulin as a Potential Backbone Drug Across Multiple ADC Combinations

ADCs are increasingly being tested in earlier lines of cancer treatment and in combination with immunotherapy. However, recent large Phase 3 studies — TROPION-Lung01 and EVOKE-01 — showed that leading ADCs failed to outperform older chemotherapy, such as docetaxel, in certain lung cancer settings, underscoring the need for an agent that can improve the efficacy and tolerability of ADC-based combinations.

Plinabulin's ability to simultaneously boost efficacy and reduce toxicity positions it as a potential backbone agent across the ADC landscape — a role no other drug currently fills. Today's AACR data open the door to ADC combination studies as a natural next chapter in Plinabulin's clinical development, alongside the ongoing DUBLIN-4 confirmatory program.

"Plinabulin has the potential to enable ADC therapy to deliver on its full promise — producing more complete responses, extending survival, and keeping patients on treatment. These AACR data further strengthen our conviction in Plinabulin's combination potential, as we advance the DUBLIN-4 confirmatory Phase 3 program in NSCLC post immune checkpoint inhibitors and explore the broader opportunity in ADC-based regimens."

— Dr. Lan Huang, Co-Founder, Chairman, and CEO, BeyondSpring Inc.

BeyondSpring's China operations have been a strategic engine in building the ADC partnerships that support Plinabulin's global development.

"China's ADC research ecosystem is among the most active in the world, and BeyondSpring is well-positioned to leverage those capabilities. Our collaboration with Shanghai Chest Hospital demonstrated the value of strategic partnerships in advancing Plinabulin's preclinical and clinical development in ADC combination, and we see continued opportunity to build on that model as the ADC combination landscape evolves."

— Min Qiu, Deputy General Manager, BeyondSpring China

BeyondSpring's AACR 2026 Presentation

Title: Plinabulin Boosts Antitumor Efficacy of Topoisomerase Inhibitor-Based Antibody-Drug Conjugates Without or With Immune Checkpoint Inhibitor

Presenters: Yingjuan June Lu, Xiaoyan He, Weiwei Cheng, Zhengyan Zhang, James Tonra, Lan Huang

Session: T Cell Engagers 2 / Antibody-Drug Conjugates 1 (Immunology Track)

Poster Number: 5597

About Plinabulin

Plinabulin is a late-stage Phase 3 anticancer agent and first-in-class GEF-H1 (guanine nucleotide exchange factor H1) agonist. Its multifunctional mechanism — encompassing dendritic cell maturation, tumor microenvironment modulation, anti-angiogenesis, and chemotherapy-induced neutropenia (CIN) mitigation — activates biological pathways that standard chemotherapy and ADCs do not. Over 700 cancer patients have been treated with good tolerability and durable anticancer benefit in rational combination settings. DUBLIN-3 Phase 3 results in NSCLC were published in The Lancet Respiratory Medicine in 2024.

About DUBLIN-3 and the Path to DUBLIN-4

In the DUBLIN-3 Phase 3 study of 2L/3L EGFR wild-type NSCLC (Lancet Respiratory Medicine, 2024), Plinabulin plus docetaxel significantly outperformed docetaxel monotherapy (n=559, 1:1 randomization), with improvements in OS, PFS, and ORR; doubling of 2- and 3-year survival rates; and reduction of docetaxel-induced grade 4 neutropenia from 33% to 5% (p<0.0001).

DUBLIN-4 is BeyondSpring's planned FDA-aligned confirmatory Phase 3 program (n=442, 1:1 randomization), designed to validate the DUBLIN-3 results in a prospective confirmatory setting in a patient population selected based on Plinabulin's mechanism of action: non-squamous NSCLC patients who have progressed on PD-1/L1 inhibitors. The ADC preclinical data presented at AACR 2026 broaden the scientific case for Plinabulin's combination potential.

About BeyondSpring

BeyondSpring (NASDAQ:BYSI) is a clinical-stage biopharmaceutical company developing first-in-class therapies for cancers with high unmet need. Its lead asset, Plinabulin, has been studied in over 700 cancer patients and is in late-stage development across multiple cancer indications, with results published in The Lancet Respiratory Medicine. More at beyondspringpharma.com.

Investor Contact: IR@beyondspringpharma.com

Media Contact: PR@beyondspringpharma.com

Selected References

Han et al (2024). Plinabulin plus docetaxel versus docetaxel in NSCLC after platinum progression (DUBLIN-3). Lancet Respir Med 12(10):775-786.
Ahn M-J et al (2024). Datopotamab deruxtecan versus docetaxel in previously treated advanced NSCLC (TROPION-Lung01). J Clin Oncol 43(3):260-272.
Paz-Ares LG et al (2024). Sacituzumab govitecan versus docetaxel in advanced NSCLC (EVOKE-01). J Clin Oncol 42(24):2860-2872.
Choi SR et al (2026). Structural basis of microtubule-mediated signal transduction. Cell 189(2):461-477.
Kashyap AS et al (2019). GEF-H1 signaling upon microtubule destabilization is required for dendritic cell activation and specific anti-tumor responses. Cell Rep 28(13):3367-3380.
Tonra JR et al (2020). Plinabulin ameliorates neutropenia induced by multiple chemotherapies through a mechanism distinct from G-CSF therapies. Cancer Chemother Pharmacol 85(2):461-468.
Lin SH et al (2025). Plinabulin following radiation enhances dendritic cell maturation and checkpoint inhibitor retreatment. Med 6(10):100752.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements involve known and unknown risks and uncertainties that may cause BeyondSpring's actual results to differ materially from those stated or implied. BeyondSpring undertakes no obligation to update forward-looking statements.

BeyondSpring Reports Compelling New Data: Plinabulin Advances Both the Anticancer Efficacy and Safety of ADC Drugs

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