iTeos Reports Topline Interim Results from GALAXIES Lung-201 Study of Belrestotug + Dostarlimab in First-Line, PD-L1 High Non-Small Cell Lung Cancer Patients
iTeos Therapeutics (NASDAQ: ITOS) reported disappointing topline results from the GALAXIES Lung-201 Phase 2 study evaluating belrestotug + dostarlimab combination in first-line PD-L1 high non-small cell lung cancer (NSCLC). While the study showed improvements in objective response rate (ORR), it failed to meet criteria for meaningful progression-free survival improvements. Additionally, interim analysis of GALAXIES H&N-202 Phase 2 trial showed below-threshold results in head and neck cancer.
Following these results, iTeos and GSK have decided to terminate the belrestotug development program and end their collaboration. The company is halting all belrestotug-containing cohorts and new enrollment in the GALAXIES Lung-301 Phase 3 trial. iTeos has engaged TD Cowen to explore strategic alternatives to maximize shareholder value.
iTeos Therapeutics (NASDAQ: ITOS) ha riportato risultati deludenti dai primi dati dello studio di Fase 2 GALAXIES Lung-201, che valutava la combinazione belrestotug + dostarlimab nel trattamento di prima linea del carcinoma polmonare non a piccole cellule (NSCLC) con alto livello di PD-L1. Sebbene lo studio abbia evidenziato miglioramenti nel tasso di risposta obiettiva (ORR), non ha raggiunto i criteri per un miglioramento significativo della sopravvivenza libera da progressione. Inoltre, l'analisi intermedia dello studio di Fase 2 GALAXIES H&N-202 ha mostrato risultati al di sotto della soglia attesa nel carcinoma testa-collo.
In seguito a questi risultati, iTeos e GSK hanno deciso di interrompere il programma di sviluppo di belrestotug e di terminare la loro collaborazione. L'azienda ha sospeso tutti i coorti contenenti belrestotug e le nuove iscrizioni allo studio di Fase 3 GALAXIES Lung-301. iTeos ha incaricato TD Cowen di esplorare alternative strategiche per massimizzare il valore per gli azionisti.
iTeos Therapeutics (NASDAQ: ITOS) informó resultados decepcionantes en los datos preliminares del estudio de Fase 2 GALAXIES Lung-201, que evaluaba la combinación de belrestotug + dostarlimab en el tratamiento de primera línea del cáncer de pulmón no microcítico (NSCLC) con alta expresión de PD-L1. Aunque el estudio mostró mejoras en la tasa de respuesta objetiva (ORR), no cumplió con los criterios para una mejora significativa en la supervivencia libre de progresión. Además, el análisis intermedio del ensayo de Fase 2 GALAXIES H&N-202 mostró resultados por debajo del umbral esperado en cáncer de cabeza y cuello.
Tras estos resultados, iTeos y GSK han decidido terminar el programa de desarrollo de belrestotug y finalizar su colaboración. La compañía ha detenido todos los cohortes con belrestotug y la nueva inscripción en el ensayo de Fase 3 GALAXIES Lung-301. iTeos ha contratado a TD Cowen para explorar alternativas estratégicas que maximicen el valor para los accionistas.
iTeos Therapeutics (NASDAQ: ITOS)는 1차 치료제로 PD-L1 고발현 비소세포폐암(NSCLC)에서 벨레스토텅(belrestotug)과 도스타를리맙(dostarlimab) 병용요법을 평가한 GALAXIES Lung-201 2상 시험의 초기 결과가 실망스럽다고 보고했습니다. 객관적 반응률(ORR)에서는 개선이 있었으나 무진행 생존기간(PFS)의 의미 있는 개선 기준을 충족하지 못했습니다. 또한 GALAXIES H&N-202 2상 시험의 중간 분석 결과 구강두경부암에서 기대 이하의 결과를 보였습니다.
이러한 결과에 따라 iTeos와 GSK는 벨레스토텅 개발 프로그램을 종료하고 협력을 중단하기로 결정했습니다. 회사는 벨레스토텅이 포함된 모든 코호트와 GALAXIES Lung-301 3상 시험의 신규 등록을 중단했습니다. iTeos는 주주 가치를 극대화하기 위한 전략적 대안을 모색하기 위해 TD Cowen과 협력하고 있습니다.
iTeos Therapeutics (NASDAQ : ITOS) a annoncé des résultats décevants des premiers résultats de l'étude de phase 2 GALAXIES Lung-201, évaluant la combinaison belrestotug + dostarlimab en première ligne du cancer du poumon non à petites cellules (NSCLC) avec un taux élevé de PD-L1. Bien que l'étude ait montré une amélioration du taux de réponse objective (ORR), elle n'a pas atteint les critères d'amélioration significative de la survie sans progression. De plus, l'analyse intermédiaire de l'essai de phase 2 GALAXIES H&N-202 a révélé des résultats inférieurs au seuil attendu dans le cancer de la tête et du cou.
Suite à ces résultats, iTeos et GSK ont décidé de mettre fin au programme de développement de belrestotug et de leur collaboration. La société arrête tous les cohortes contenant belrestotug et les nouvelles inclusions dans l'essai de phase 3 GALAXIES Lung-301. iTeos a mandaté TD Cowen pour explorer des alternatives stratégiques afin de maximiser la valeur pour les actionnaires.
iTeos Therapeutics (NASDAQ: ITOS) meldete enttäuschende Zwischenergebnisse der Phase-2-Studie GALAXIES Lung-201, in der die Kombination aus Belrestotug + Dostarlimab in der Erstlinientherapie von NSCLC mit hohem PD-L1-Status untersucht wurde. Obwohl die Studie Verbesserungen der objektiven Ansprechrate (ORR) zeigte, wurden die Kriterien für eine signifikante Verbesserung des progressionsfreien Überlebens nicht erfüllt. Zudem zeigte die Zwischenanalyse der Phase-2-Studie GALAXIES H&N-202 bei Kopf-Hals-Tumoren unterdurchschnittliche Ergebnisse.
Aufgrund dieser Ergebnisse haben iTeos und GSK beschlossen, das Belrestotug-Entwicklungsprogramm einzustellen und ihre Zusammenarbeit zu beenden. Das Unternehmen stoppt alle Kohorten mit Belrestotug sowie die Neueinschreibung in die Phase-3-Studie GALAXIES Lung-301. iTeos hat TD Cowen beauftragt, strategische Alternativen zur Maximierung des Aktionärswerts zu prüfen.
- Study showed clinically meaningful improvements in objective response rate (ORR)
- Company maintains a strong balance sheet
- Company taking immediate action to preserve capital
- Failed to meet criteria for clinically meaningful improvements in progression-free survival
- GALAXIES H&N-202 trial showed below-threshold results in head and neck cancer
- Complete termination of belrestotug development program
- End of collaboration with GSK
- Halting of all ongoing TIGIT studies
Insights
iTeos' lead TIGIT drug fails key lung cancer trial metric, prompting program termination and strategic review of company's future.
This announcement represents a significant setback for iTeos Therapeutics and their immunotherapy program. The Phase 2 GALAXIES Lung-201 study evaluated the combination of belrestotug (a TIGIT inhibitor) with dostarlimab in first-line PD-L1 high non-small cell lung cancer patients. While the combination showed improvement in the primary endpoint of objective response rate (ORR), it critically failed to demonstrate clinically meaningful improvements in progression-free survival (PFS) compared to dostarlimab monotherapy.
The failure in PFS is particularly damaging because this outcome measure is often more predictive of overall survival benefit and regulatory approval than response rates alone. A drug that increases tumor shrinkage (ORR) but doesn't meaningfully delay disease progression offers limited clinical benefit to patients.
Further compounding this negative data, the GALAXIES H&N-202 trial in head and neck cancer showed suboptimal response rates, indicating the mechanism may have limited efficacy across multiple tumor types. The comprehensive termination of the entire belrestotug program (including halting the ongoing Phase 3 GALAXIES Lung-301 trial) signals that both iTeos and GSK see no viable path forward for this agent.
Most significantly, iTeos has initiated a "targeted review of strategic alternatives" and engaged TD Cowen as an advisor. In biotech, this language typically indicates the company is considering major strategic options such as a merger, acquisition, asset sales, or significant restructuring. The CEO's emphasis on "preserving capital" and "maximizing shareholder value" further reinforces that iTeos is pivoting from drug development to company preservation.
The complete absence of discussion about other pipeline assets or development programs in the announcement suggests the company had heavily prioritized the TIGIT program, and alternative clinical candidates may be limited or early-stage. For a clinical-stage biotech company, the termination of a lead program and collaboration with a major partner like GSK represents a fundamental challenge to the business model.
– GALAXIES Lung-201 did not meet established criteria for clinically meaningful improvements in progression free survival
– Based on totality of data, iTeos and GSK have agreed to terminate the belrestotug development program
– iTeos has initiated a targeted review of strategic alternatives to maximize shareholder value
WATERTOWN, Mass. and GOSSELIES, Belgium, May 13, 2025 (GLOBE NEWSWIRE) -- iTeos Therapeutics, Inc. (Nasdaq: ITOS), a clinical-stage biopharmaceutical company pioneering the discovery and development of a new generation of immuno-oncology therapeutics for patients, today reported topline results from an updated interim analysis of GALAXIES Lung-201, the Phase 2 platform study sponsored by iTeos’ development partner GSK assessing the belrestotug + dostarlimab doublet in previously untreated, unresectable, locally advanced or metastatic PD-L1 high non-small cell lung cancer (NSCLC).
The GALAXIES Lung-201 data continued to demonstrate clinically meaningful improvements in the trial’s primary endpoint of objective response rate (ORR), however the analysis did not meet established criteria for clinically meaningful improvements in the secondary endpoint of progression free survival in the belrestotug + dostarlimab combination cohorts versus dostarlimab monotherapy. Additionally, an interim analysis of the GALAXIES H&N-202 Phase 2 trial showed a trend below the meaningful threshold for ORR in the belrestotug combination cohorts vs. dostarlimab monotherapy in PD-L1 positive head and neck squamous cell carcinoma.
Based on these results, iTeos and GSK have made the decision to terminate the belrestotug development program and end the collaboration. All belrestotug-containing cohorts are ending, and any new enrollment in the ongoing GALAXIES Lung-301 Phase 3 trial is ending. GSK is communicating with investigators, institutional review boards, ethics committees, and health authorities about next steps for appropriate management of currently enrolled patients. The Company is taking immediate steps to preserve capital and has initiated a targeted process to identify opportunities that preserve and maximize shareholder value. iTeos has engaged TD Cowen to advise on this process.
“We are truly disappointed by the results from GALAXIES Lung-201,” said Michel Detheux, Ph.D., president and chief executive officer of iTeos. “Following the analysis of the TIGIT data generated to-date with GSK, we have made the mutual decision to discontinue development of all ongoing TIGIT studies. We are grateful to all patients, caregivers, and investigators involved in the GALAXIES studies and believe it is important to share these data with the scientific community at an upcoming medical meeting in order to advance our collective understanding of immuno-oncology and TIGIT.”
“Since founding this company over a decade ago, I could not be prouder of the team we have built, the quality of science produced, and our collective commitment to improving the lives of cancer patients in need. However, given current market conditions and our appreciation of the responsibility to our valued shareholders, we believe the best path forward is to promptly evaluate a full range of strategic alternatives to unlock the value of our assets. With a strong balance sheet and a commitment to disciplined execution, we are well positioned to pursue opportunities that maximize shareholder value,” continued Dr. Detheux.
About iTeos Therapeutics, Inc.
iTeos Therapeutics is a clinical-stage biopharmaceutical company pioneering the discovery and development of a new generation of immuno-oncology therapeutics for patients. iTeos Therapeutics leverages its deep understanding of tumor immunology and immunosuppressive pathways to design novel product candidates with the potential to restore the immune response against cancer. iTeos Therapeutics is headquartered in Watertown, MA with a research center in Gosselies, Belgium.
About Belrestotug (EOS-448/ GSK4428859A)
Belrestotug is an Fc active human immunoglobulin G1, or IgG1, monoclonal antibody (mAb) targeting T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT), an important inhibitory receptor which contributes to the suppression of adaptive and innate immune responses against cancer. As an optimized high-affinity, potent anti-TIGIT mAb, belrestotug is designed to enhance the antitumor response through a multifaceted immune modulatory mechanism by engaging with TIGIT and FcγR, a key regulator of immune responses which induces cytokine release and antibody dependent cellular cytotoxicity (ADCC).
Forward-Looking Statements
This press release contains forward-looking statements. Any statements that are not solely statements of historical fact are forward-looking statements. Words such as “believe,” “anticipate,” “plan,” “expect,” “will,” “may,” “intend,” “prepare,” “look,” “potential,” “possible” and similar expressions are intended to identify forward-looking statements. These forward-looking statements include statements relating to iTeos’ steps to preserve capital and review and identify opportunities to maximize shareholder value.
These forward-looking statements involve risks and uncertainties, many of which are beyond iTeos’ control. Actual results could materially differ from those stated or implied by these forward-looking statements as a result of such risks and uncertainties. Known risk factors include the following: risks relating to volatility and uncertainty in the capital markets for biotechnology companies; whether iTeos will be able to identify opportunities to maximize shareholder value and whether iTeos will be able to execute on such opportunities on attractive terms or timing, or at all; whether any capital preservation strategies undertaken will be effective; and those risks identified under the heading “Risk Factors” in iTeos’ Annual Report on Form 10-K for the period ended December 31, 2024 filed with the Securities and Exchange Commission (SEC) as well as other SEC filings made by iTeos which you are encouraged to review.
Any of the foregoing risks could materially and adversely affect iTeos’ business, results of operations and the trading price of iTeos’ common stock. We caution investors not to place undue reliance on the forward-looking statements contained in this press release. iTeos does not undertake any obligation to publicly update its forward-looking statements other than as required by law.

For further information, please contact: Investor Contact: Carl Mauch iTeos Therapeutics, Inc. carl.mauch@iteostherapeutics.com Media Contact: media@iteostherapeutics.com