OPKO Health’s ModeX Therapeutics Begins Clinical Trial of Tetraspecific Antibody for Treatment of B-cell Lymphomas

Rhea-AI Summary

OPKO Health (NASDAQ: OPK) subsidiary ModeX Therapeutics began dosing patients in a Phase 1 safety and tolerability study of MDX2003, a first‑in‑class tetraspecific T‑cell engager for relapsed or refractory B‑cell lymphoma, on April 22, 2026.

The drug targets CD19 and CD20 on tumor cells plus CD3 and CD28 on T cells; preclinical data and dose‑selection analyses were presented at ASH 2025 and ESMO TAT 2026.

Positive

• Patients dosed in Phase 1 study (MDX-2003-101), marking clinical milestone
• MDX2003 is a tetraspecific design targeting CD19, CD20, CD3, and CD28
• Preclinical data and dose‑selection analyses presented at ASH 2025 and ESMO TAT 2026

Negative

• Study is first‑in‑human Phase 1; safety and efficacy outcomes are currently unknown
• Trial focuses on relapsed/refractory patients where 30–40% historically relapse or progress after initial chemoimmunotherapy

News Market Reaction – OPK

+0.82%

+0.82% Session close to close

In the Apr 22 session, OPK gained 0.82%, reflecting a mild positive market reaction.

Data tracked by StockTitan Argus on the day of publication.

Market Context

This announcement marks ModeX’s entry of MDX2003 into a Phase 1 trial for relapsed or refractory B‑c...

Analysis

This announcement marks ModeX’s entry of MDX2003 into a Phase 1 trial for relapsed or refractory B‑cell lymphomas, targeting CD19, CD20, CD3 and CD28. It extends OPKO’s strategy of advancing multispecific antibody programs into early human studies. With the stock trading below its 200-day MA at $1.22, investors may track enrollment progress, emerging safety data, and how this trial complements existing ModeX assets and partnerships.

Key Figures

Disease share: 85% Relapse/progression rate: 30–40% Trial phase: Phase 1 +1 more

4 metrics

Disease share 85% B-cell lymphoma share of non-Hodgkin lymphoma cases

Relapse/progression rate 30–40% Patients with relapse, progression, or refractory disease after initial chemoimmunotherapy

Trial phase Phase 1 MDX2003 safety and tolerability study in adult B-cell lymphoma

Study identifier NCT07249905 Clinical trial ID for MDX-2003-101 study

Previous Clinical trial Reports

2 past events · Latest: Oct 28 (Positive)

Same Type Pattern 2 events

Date	Event	Sentiment	24h Move	Catalyst
Oct 28	Clinical trial start	Positive	-0.7%	First patient dosed in Phase 1/2a trial of MDX2004 T cell rejuvenator.
Jan 07	Clinical trial start	Positive	+4.1%	Phase I trial initiation for EBV vaccine MDX2201 in Merck collaboration.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Clinical trial initiations for ModeX programs have produced mixed, generally modest one-day moves, with one positive and one negative reaction.

Recent Company History

Over the past year, OPKO’s ModeX subsidiary reported multiple clinical trial initiations, including MDX2004 in a Phase 1/2a cancer study on Oct 28, 2025 and an EBV vaccine Phase I study with Merck on Jan 7, 2025. Price reactions were modest (‑0.69% and +4.14%). Today’s MDX2003 B‑cell lymphoma trial continues this strategy of advancing multispecific antibody assets into early-stage human studies.

Key Terms

tetraspecific, t-cell engager, cd19, cd20, +4 more

8 terms

tetraspecific medical

"first-in-class tetraspecific T-cell engager, MDX2003, for relapsed or refractory B-cell lymphoma"

A tetraspecific biologic is an engineered therapeutic protein, often an antibody, designed to attach to four different molecular targets at once. Think of it like a Swiss Army knife that can engage multiple parts of a disease process simultaneously; for investors this means potential for greater effectiveness or novel treatment approaches but also higher technical complexity, development risk, and manufacturing cost that can affect valuation and timelines.

t-cell engager medical

"a novel T-cell engager designed to optimize killing of lymphomas"

A T-cell engager is a type of medicine designed to help the body's immune system attack cancer cells more effectively. It works by acting like a bridge that brings immune cells (T-cells) close to cancer cells, prompting a targeted attack. For investors, T-cell engagers are significant because they represent innovative treatments that could lead to new growth opportunities in the healthcare and biotech sectors.

cd19 medical

"targets two proteins found on the surface of B-cell malignancies, CD19 and CD20"

CD19 is a protein found on the surface of most B cells, a type of immune cell; think of it as a distinctive nametag that helps identify and track these cells. It matters to investors because many cancer and autoimmune treatments, diagnostics, and lab tests are designed to target or detect CD19—so advances, approvals, or setbacks in CD19‑focused therapies can directly affect drug pipelines, regulatory value, and potential revenue for healthcare companies.

cd20 medical

"targets two proteins found on the surface of B-cell malignancies, CD19 and CD20"

CD20 is a protein that sits on the surface of a subset of white blood cells called B cells, acting like a nametag that lets medicines and tests recognize those cells. It matters to investors because many treatments and diagnostics are built to seek out that nametag, so drugs that bind CD20 can drive clinical trial value, regulatory outcomes and sales potential, while changes in safety or effectiveness can materially affect a company’s prospects.

cd3 medical

"along with the CD3 and CD28 co-stimulatory T-cell activators"

CD3 is a group of proteins on the surface of T cells, the immune system’s front-line soldiers, that act like a control panel to turn those cells on and off. It matters to investors because many modern therapies work by engaging or blocking CD3 to direct T cells against cancer or dampen harmful immune reactions; success, safety and regulatory approval of CD3-targeting drugs can significantly affect a biotech company’s prospects.

cd28 medical

"along with the CD3 and CD28 co-stimulatory T-cell activators"

A protein found on the surface of T cells that acts like a gas pedal for the immune system: when it receives the right signal it helps activate T cells to attack infections or abnormal cells. Investors care because therapies or drugs that target this protein can boost or dial back immune responses, affecting how well treatments for cancer, autoimmune disease, or vaccines work and their safety profile—key factors in drug value and regulatory risk.

pharmacokinetic medical

"designed to evaluate the safety, tolerability, pharmacokinetic, and immune activity of MDX2003"

Pharmacokinetic describes how a drug moves through and leaves the body — how it is absorbed, spread to tissues, broken down and excreted — like tracking a package from pickup to delivery and disposal. For investors, these properties determine effective dose, safety risks, how often a medicine must be taken, and how reliably it works, which in turn influence clinical trial success, regulatory approval chances, production complexity and a drug’s commercial value.

chemoimmunotherapy medical

"refractory disease following initial chemoimmunotherapy2"

Chemoimmunotherapy is a cancer treatment approach that combines drugs that directly kill tumor cells with medicines that boost or guide the patient’s immune system to recognize and attack cancer. For investors, it matters because combining these two approaches can change clinical trial outcomes, regulatory paths, potential sales and pricing, and the risk/reward profile of drug candidates much like adding a second player to a team can improve performance but also complicate strategy and costs.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Patients dosed in Phase 1 safety and tolerability study of MDX2003, a novel T-cell engager designed to optimize killing of lymphomas

Preclinical studies presented at 2025 American Society of Hematology (ASH) Annual Meeting and ESMO Targeted Anticancer Therapies Congress 2026

WESTON, Mass., April 22, 2026 (GLOBE NEWSWIRE) -- ModeX Therapeutics Inc., an OPKO Health company (NASDAQ: OPK), today announced the dosing of patients with its first-in-class tetraspecific T-cell engager, MDX2003, for relapsed or refractory B-cell lymphoma. This multispecific antibody targets two proteins found on the surface of B-cell malignancies, CD19 and CD20, along with the CD3 and CD28 co-stimulatory T-cell activators to sustain T cell killing of these tumors.

The MDX-2003-101 study (NCT07249905) is designed to evaluate the safety, tolerability, pharmacokinetic, and immune activity of MDX2003 in adult patients with various types of B-cell lymphoma. The study includes dose-escalation and dose-expansion phases. B-cell lymphoma, a form of non-Hodgkin lymphoma arising from B lymphocytes, represents the most common lymphoma subtype, accounting for approximately 85% of cases¹. Despite available therapies, an estimated 30–40% of patients experience disease relapse, progression, or refractory disease following initial chemoimmunotherapy².

“This clinical trial represents a significant milestone for ModeX,” said Giovanni Abbadessa, M.D., Ph.D., Chief Medical Officer of ModeX Therapeutics. “MDX2003 is designed to address limitations of current T‑cell-engagers by combining dual tumor antigen targeting with optimized T‑cell activation. This first‑in‑human study will allow us to assess safety and biologic activity in patients with advanced B‑cell lymphoma.”

Preclinical proof-of-concept data, along with analyses supporting clinical dose selection, were presented in poster presentations at the 2025 American Society of Hematology (ASH) Annual Meeting and ESMO Targeted Anticancer Therapies Congress 2026.

“MDX2003 takes advantage of our proprietary multispecific antibody design to optimize tumor killing and address the problem of immune escape in the treatment of lymphoma,” said Phillip Frost, M.D., Chairman and CEO of OPKO Health, and Gary Nabel, M.D., Ph.D., President and CEO of ModeX and Chief Innovation Officer of OPKO Health. “This study will define dosing and treatment regimens for future efficacy trials.”

About MDX2003

MDX2003 is a novel tetraspecific T-cell engager targeting CD19 and CD20 on B cells and CD3 and CD28 on T cells. This dual B-cell targeting strategy is intended to mitigate the impact of tumor antigen loss, while CD3/CD28 co-stimulation aims to promote robust T-cell activation, survival, and sustained cytotoxic activity. Preclinical studies have demonstrated potent anti-tumor activity and balanced T-cell activation, supporting advancement into clinical evaluation³.

About ModeX Therapeutics

ModeX Therapeutics is a clinical-stage biopharmaceutical company developing innovative multispecific biologics for cancer, immunology, and infectious diseases. Its platforms unite the power of multiple biologics in a single molecule to create multispecific antibody therapeutics designed to address complex diseases. The ModeX pipeline includes first-in-class candidates for oncology indications against both solid and hematologic tumors, autoimmune and immunological diseases, and for infectious disease indications against the most pressing viral threats. Its founding team includes globally recognized medical innovators with proven track records of delivering breakthrough medicines for patients. ModeX Therapeutics Inc., an OPKO Health company (NASDAQ: OPK), is based in Weston, Massachusetts. For more information, visit www.modextx.com.

About OPKO Health, Inc.

OPKO is a multinational biopharmaceutical and diagnostics company that seeks to establish industry-leading positions in large, rapidly growing markets by leveraging its discovery, development and commercialization expertise, and novel and proprietary technologies. For more information, visit www.opko.com.

Cautionary Statement Regarding Forward-Looking Statements

This press release contains "forward-looking statements," as that term is defined under the Private Securities Litigation Reform Act of 1995 (PSLRA), which statements may be identified by words such as "expects," "plans," "projects," "will," “could,” "may," "anticipates," "believes," "should," "intends," "estimates," and other words of similar meaning, including whether and when we will complete the clinical studies contemplated for MDX2003 and whether final study data will be positive, whether data will support marketing approval, our ability to develop and commercialize MDX2003, whether MDX2003 is capable of effectively treating  patients with certain cancers,  whether MDX2003 will be safe, or have any impact on the severity of disease, expectations regarding the product, its efficacy, safety and market potential as well as other non-historical statements about our expectations, beliefs or intentions regarding our business, technologies and products, financial condition, strategies or prospects. Many factors could cause our actual activities or results to differ materially from the activities and results anticipated in forward-looking statements. These factors include those described in our Annual Reports on Form 10-K filed and to be filed with the Securities and Exchange Commission and in our other filings with the Securities and Exchange Commission, as well as liquidity issues and the risks inherent in funding, developing and obtaining regulatory approvals of new, commercially-viable and competitive products and treatments, the success of our relationship with our commercial partners, that earlier clinical results of effectiveness and safety may not be reproducible or indicative of future results, and that currently available over-the-counter and prescription products, as well as products under development by others, may prove to be as or more effective than our products for the indications being studied. In addition, forward-looking statements may also be adversely affected by general market factors, competitive product development, product availability, federal and state regulations and legislation, the regulatory process for new products and indications, manufacturing issues that may arise, patent positions and litigation, among other factors. The forward-looking statements contained in this press release speak only as of the date the statements were made, and we do not undertake any obligation to update forward-looking statements. We intend that all forward-looking statements be subject to the safe-harbor provisions of the PSLRA.

Contacts:

Investors:
Alliance Advisors IR
Yvonne Briggs, 310-691-7100
ybriggs@allianceadvisors.com
or
Bruce Voss, 310-691-7100
bvoss@allianceadvisors.com

Media:
ModeX Media Relations
media@modextx.com

¹Silkenstedt E, Salles G, Campo E, Dreyling M. B-cell non-Hodgkin lymphomas. Lancet. 2024 May 4;403(10438):1791-1807. doi: 10.1016/S0140-6736(23)02705-8. PMID: 38614113; PMCID: PMC12261310.
²Sehn L.H., Salles G. Diffuse Large B-Cell Lymphoma. N. Engl. J. Med. 2021;384:842–858. doi: 10.1056/NEJMra2027612.
³Wei R, Wu L, Kramer J et al. MDX2003, a novel tetraspecific T-cell engager-expander targeting CD19xCD20xCD3xCD28, demonstrates potent preclinical activity against B-cell malignancies. Presented at: ASH 2025; December 6-9, 2025; Orlando, FL. Paper 3311.

FAQ

What is MDX2003 and what does OPK announce about it on April 22, 2026?

MDX2003 is a first‑in‑class tetraspecific T‑cell engager; ModeX has begun dosing patients in a Phase 1 safety study. According to the company, the molecule targets CD19, CD20, CD3 and CD28 to sustain T‑cell killing in B‑cell lymphoma.

Which patients are eligible for the MDX-2003-101 study (OPK) and what are study goals?

Eligible adults have relapsed or refractory B‑cell lymphoma; the trial includes dose‑escalation and expansion phases. According to the company, the study will evaluate safety, tolerability, pharmacokinetics, and immune activity of MDX2003.

How does MDX2003 differ from existing T‑cell engagers in the OPK program?

MDX2003 is tetraspecific, binding two tumor antigens plus two T‑cell activators to sustain T‑cell activity. According to the company, dual tumor targeting and CD28 co‑stimulation aim to address immune escape limitations of current engagers.

What preclinical support exists for MDX2003 and when was it presented?

Preclinical proof‑of‑concept and dose‑selection analyses were presented at major conferences in 2025–2026. According to the company, data were shown at ASH 2025 and ESMO Targeted Anticancer Therapies Congress 2026 to support clinical dosing.

What is the immediate investor implication of ModeX dosing patients for MDX2003 (OPK)?

Dosing initiation is an early clinical milestone that may de‑risk preclinical-to‑human transition but does not guarantee efficacy. According to the company, this Phase 1 study will define dosing and inform future efficacy trials.