GSK lung cancer drug posts 94% response rate

GSK reports strong ARROS-1 data for Jideytro in first-line ROS1-positive NSCLC and plans a US supplemental filing in 2026.

Rhea-AI Filing Summary

GSK plc (GSK) reported positive registrational phase I/II ARROS-1 data for its ROS1 tyrosine kinase inhibitor Jideytro (zidesamtinib) in TKI‑naïve patients with advanced or metastatic ROS1‑positive non-small cell lung cancer. In 94 efficacy‑evaluable patients, Jideytro achieved a 94% objective response rate, including a 15% complete response rate, after a median follow‑up of 15.2 months. Responses appeared durable, with 94% of patients still responding at nine months and 86% at 12 months; 12‑month progression‑free survival was 90%, while median duration of response and median PFS were not yet reached.

All patients with measurable brain metastases (10/10) responded, and 70% achieved complete clearance of detectable brain tumours, with 78% maintaining intracranial response at 12 months. Treatment‑related adverse events were mostly low grade; dose reductions occurred in 11% of patients and discontinuations in 1%. GSK plans a supplemental New Drug Application in the US in 2026 to seek expansion of Jideytro’s indication to first-line ROS1‑positive NSCLC, adding to its July 2026 US approval in previously TKI‑treated patients.

Filing Explained

The September 14, 2026 Form 6-K reports first-line trial results, but they do not change authorization: Jideytro is approved for previously treated patients, while first-line use remains unapproved pending GSK’s planned supplemental US application in 2026.

Key Figures

Objective response rate (ORR): 94% Complete response rate: 15% Median follow-up: 15.2 months +5 more

8 metrics

Objective response rate (ORR) 94% TKI-naïve ROS1-positive NSCLC patients in ARROS-1 efficacy-evaluable population (88/94)

Complete response rate 15% Complete responses among 94 efficacy-evaluable TKI-naïve patients (14/94)

Median follow-up 15.2 months Follow-up duration for efficacy-evaluable population in ARROS-1 (range 1.1–30.5 months)

12-month progression-free survival 90% Progression-free survival rate at 12 months in TKI-naïve ROS1-positive NSCLC patients

Intracranial complete clearance 70% Patients with measurable brain metastases achieving complete clearance of detectable brain tumours (7/10)

Dose reductions due to TRAEs 11% Patients requiring dose reductions from treatment-related adverse events in ARROS-1

Discontinuations due to TRAEs 1% Patients discontinuing Jideytro because of treatment-related adverse events in ARROS-1

Incidence of ROS1 mutations in NSCLC 2% Estimated share of NSCLC cases with ROS1 mutations, about 50,000 new diagnoses annually

Key Terms

objective response rate, progression-free survival, tyrosine kinase inhibitor, treatment-related adverse events, +2 more

6 terms

objective response rate medical

"zidesamtinib achieved a clinically meaningful 94% objective response rate (ORR)"

The objective response rate (ORR) is the percentage of patients in a clinical trial whose tumors measurably shrink or disappear according to preset rules. Investors use it as a quick, objective signal of a drug’s ability to produce a clear treatment effect—like counting how many plants visibly respond after applying a new fertilizer—and higher ORR can improve odds of regulatory approval, commercial success, and company valuation.

progression-free survival medical

"Progression-free survival (PFS) was 90% at 12 months."

Progression-free survival is the length of time during and after a treatment that a patient's disease does not get worse, measured from the start of treatment until the disease shows measurable signs of progression or the patient dies. Investors care because longer progression-free survival in clinical trials often signals that a drug is effective, improving chances of regulatory approval, market adoption, and revenue potential—think of it as a stopwatch showing how long a therapy can keep the illness at bay.

tyrosine kinase inhibitor medical

"who had not received previous treatment with a tyrosine kinase inhibitor (TKI-naïve)."

A tyrosine kinase inhibitor is a type of drug that blocks specific proteins in cells that act like on/off switches for growth and survival signals, often used to stop cancer cells from multiplying. For investors, these drugs matter because their clinical trial results, regulatory approvals, safety profiles, and patent status drive sales potential and company valuation—think of them as precision tools whose effectiveness and market exclusivity determine commercial success.

treatment-related adverse events medical

"The most common (≥15%) treatment-related adverse events (TRAEs) were peripheral oedema"

Treatment-related adverse events are harmful or unwanted health effects that doctors or regulators determine were caused by a drug, vaccine, device, or other medical therapy. Investors care because how often and how severe these side effects are can shape regulatory approval, labeling, sales potential and legal risk — similar to how product defects can stop or damage a company's ability to sell an item.

intracranial response medical

"At 12 months, 78% of patients maintained an intracranial response"

non-small cell lung cancer medical

"ROS1-positive non-small cell lung cancer (NSCLC)"

A broad category of lung tumors that grow from the cells lining the airways and make up the majority of lung cancer cases; it includes several subtypes that behave and respond to treatment differently, like different models of the same car family. It matters to investors because its large patient population and variety of treatment options — surgery, traditional chemo, targeted drugs and immunotherapies — create major markets where clinical trial results, drug approvals or changing treatment guidelines can quickly affect a company’s revenue and stock value.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What clinical results did GSK (GSK) report for Jideytro in ROS1-positive NSCLC?

GSK reported that Jideytro (zidesamtinib) achieved a 94% objective response rate in 94 TKI-naïve patients with advanced or metastatic ROS1-positive NSCLC, with a 15% complete response rate after a median follow-up of 15.2 months.

How durable were responses to Jideytro in the ARROS-1 trial for GSK (GSK)?

Responses to Jideytro were durable, with 94% of patients still responding at nine months and 86% at 12 months. Median duration of response and median progression-free survival had not been reached at the time of analysis.

What were the brain metastasis outcomes with Jideytro in GSK’s ARROS-1 study?

Among patients with measurable brain metastases at baseline (n=10), 100% responded to Jideytro and 70% achieved complete clearance of detectable brain tumours. At 12 months, 78% maintained an intracranial response, and no CNS progression was seen in patients without baseline brain metastases.

What safety profile did GSK (GSK) report for Jideytro in ARROS-1?

GSK reported low rates of treatment discontinuation. Treatment-related adverse events led to dose reductions in 11% of patients and discontinuation in 1%. Common adverse events (≥15%) included peripheral oedema, weight increase, elevated creatine phosphokinase, dysgeusia and increased aspartate aminotransferase, mostly low grade.

What regulatory plans does GSK (GSK) have for Jideytro based on ARROS-1?

GSK stated that ARROS-1 data will support a supplemental New Drug Application to the US FDA in 2026, aiming to expand Jideytro’s indication to first-line treatment of ROS1-positive NSCLC. Jideytro is already FDA-approved for adults previously treated with a ROS1 TKI.

How common is ROS1-positive NSCLC according to GSK (GSK)?

GSK noted that ROS1 mutations occur in about 2% of non-small cell lung cancers, contributing to an estimated 50,000 new diagnoses worldwide each year, typically in younger patients and more often in non-smokers, with a high propensity to spread to the brain.

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

Form 6-K: How Foreign Companies Report to the SEC →

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Available on EDGAR 09/14/2026 - 07:04 AM Accepted by SEC EDGAR 09/14/2026 - 07:04 AM Learn about SEC filing dates

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of September 2026

Commission File Number 001-15170

GSK plc

(Translation of registrant's name into English)

79 New Oxford Street, London, WC1A 1DG

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F . . . .X. . . . Form 40-F . . . . . . . .

Issued: 14 September 2026, London UK

GSK presents positive registrational data to potentially expand Jideytro (zidesamtinib) to first-line ROS1-positive non-small cell lung cancer

●

94% objective response rate at 15.2 months follow-up

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90% of patients were progression free at 12 months, with median PFS rate still to be reached

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70% of patients with measurable brain metastases achieved complete clearance of detectable brain tumours

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Results support potential to address key efficacy and tolerability needs in ROS1-positive NSCLC with US regulatory submission planned in 2026

GSK plc (LSE/NYSE: GSK) today announced positive results from the registrational phase I/II ARROS-1 trial evaluating Jideytro (zidesamtinib) in patients with advanced or metastatic ROS1-positive non-small cell lung cancer (NSCLC) who had not received previous treatment with a tyrosine kinase inhibitor (TKI-naïve). The data were presented in a Presidential Symposium session at the 2026 World Conference on Lung Cancer (WCLC) in Seoul, South Korea, and will support a planned supplemental New Drug Application to the US FDA this year to expand the indication for Jideytro to include first-line treatment.

In the 94 TKI-naïve patients included in the analysis, zidesamtinib achieved a clinically meaningful 94% objective response rate (ORR) (88/94; 95% CI: 87-98), including a 15% complete response rate (14/94), after a median follow-up of 15.2 months (range 1.1–30.5). Responses were durable, with 94% of patients continuing to respond to treatment at nine months and 86% at 12 months. Progression-free survival (PFS) was 90% at 12 months. Median duration of response (DOR) and median PFS had not been reached at the time of analysis. In the trial, 100% of patients with measurable brain metastases at baseline (n=10) responded to zidesamtinib (10/10, 95% CI: 69–100), and 70% achieved a complete clearance of detectable brain tumours (7/10). At 12 months, 78% of patients maintained an intracranial response, and no central nervous system progression events were observed among patients without brain metastases at baseline.1

Hesham Abdullah, Senior Vice President, Global Head of Oncology, R&D, GSK said, “Today’s results show a combination of high response rates and a tolerability profile that helped most patients stay on treatment. They highlight the potential for a differentiated profile for zidesamtinib to become a first-line treatment for patients with ROS1-positive NSCLC – a condition where maintaining long-term disease control, managing spread to the brain and minimising treatment-related side effects remain key challenges. We look forward to sharing these data with regulators.”

Low rates of treatment discontinuation were observed, consistent with previous safety reports for zidesamtinib. The most common (≥15%) treatment-related adverse events (TRAEs) were peripheral oedema, weight increase, blood creatine phosphokinase increase, dysgeusia and aspartate aminotransferase increase; most were low grade. TRAEs led to dose reductions in 11% of patients and discontinuation in 1%.1

Alexander Drilon, MD, ARROS-1 primary investigator and Chief of the Early Drug Development Service at Memorial Sloan Kettering Cancer Center, said: “Patients with ROS1-positive NSCLC may receive treatment for many years while continuing to work, care for their families and live their daily lives. They need treatments that provide lasting control of their disease, including in the brain, while limiting side effects and treatment disruption. The durable responses and low rates of treatment discontinuation observed in ARROS-1 represent encouraging progress toward addressing these long-term treatment needs.”

Zidesamtinib is not approved anywhere in the world for use as first-line therapy. In July 2026, the FDA approved zidesamtinib for patients with ROS1-positive NSCLC previously treated with a TKI.2

About ARROS-1

The global, single-arm, first-in-human phase I/II ARROS-1 study (NCT05118789) included a phase II cohort of patients with locally advanced or metastatic ROS1-positive NSCLC who were naïve to ROS1 tyrosine kinase inhibitor (TKI) therapy, with up to one prior line of chemotherapy and/or immunotherapy permitted. Of 532 patients with ROS1-positive NSCLC who received zidesamtinib 100 mg once daily across all lines of therapy, 183 were receiving their first TKI-targeted treatment. The efficacy-evaluable population (n=94) included patients with measurable disease (by blinded independent central review) who initiated treatment by 15 June 2025, to allow at least nine months of follow-up for duration of response. 27% had received prior chemotherapy, 17% of whom also had prior immunotherapy. 17% had baseline central nervous system metastases by BICR. Data cut-off was 16 April 2026.

About ROS1-positive NSCLC

ROS1 mutations occur in approximately 2% of non-small cell lung cancers, contributing to an estimated 50,000 new diagnoses worldwide each year, typically in younger patients and more often in non-smokers. The disease has a high propensity to spread to the central nervous system, with brain metastases present in up to 40% of patients at diagnosis and remaining a common site of disease progression during treatment. Despite advances in targeted therapies, unmet need remains due to challenges including central nervous system progression, acquired resistance and treatment tolerability.3-6

About Jideytro

Jideytro (zidesamtinib), part of GSK’s portfolio from the recently completed acquisition of Nuvalent, Inc.7, was designed as a ROS1 TKI with broad coverage of ROS1 resistance mutations, activity against disease that has spread to the brain, durable treatment responses and a tolerable profile. Together, these features aim to help patients maintain disease control for longer while reducing the treatment challenges that can emerge over time.

Jideytro is FDA approved for the treatment of adult patients with locally advanced or metastatic ROS1-positive non-small cell lung cancer (NSCLC) who received a prior ROS1 TKI.

The US Prescribing Information is available here.8

GSK in oncology

GSK’s ambition in oncology is to help increase overall quality of life, maximise survival and change the course of disease, expanding from our current focus on blood and women’s cancers into lung and gastrointestinal cancers, as well as other solid tumours. This includes accelerating priority programmes such as antibody-drug conjugates Ris-Rez targeting B7-H3 and Mo-Rez targeting B7-H4, and velzatinib, a highly selective KIT tyrosine kinase inhibitor.

GSK’s focus in lung cancer is to develop medicines that can deliver durable responses, overcoming resistance and reducing treatment burden across small cell and non-small cell lung cancers. GSK’s lung cancer portfolio is built on validated targets and modalities where we have growing expertise, including targeted small molecules and ADCs. This approach allows us to match the right therapeutic modality to the right target, tumour type and patient need – with the bold ambition to launch multiple new options in lung cancer over the next five years.

About GSK

GSK is a global biopharma company with a purpose to unite science, technology, and talent to get ahead of disease together. Find out more at www.gsk.com.

GSK enquiries
Media:	Tim Foley	+44 (0) 20 8047 5502	(London)
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Investor Relations:	Constantin Fest	+44 (0) 7831 826525	(London)
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	Sam Piper	+44 (0) 7824 525779	(London)
	Dan Smith	+44 (0) 7823 523885	(London)
	Jeff McLaughlin	+1 215 751 7002	(Philadelphia)

Cautionary statement regarding forward-looking statements

GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described in the “Risk Factors” section in GSK’s Annual Report on Form 20-F for 2025, and GSK’s Q2 Results for 2026.

Registered in England & Wales:

No. 3888792

Registered Office:

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WC1A 1DG

References

1.

Drilon A, et al. Zidesamtinib in TKI-naive patients with advanced/metastatic ROS1+ NSCLC: ARROS-1 efficacy and safety data. Presented at: 2026 World Conference on Lung Cancer (WCLC); 12-15 September 2026; Seoul, South Korea.

2.

GSK press release issued 22 July 2026: Jideytro (zidesamtinib) approved in the US for previously treated ROS1-positive non-small cell lung cancer.

3.

Ou SI, Zhu VW. Rearranged rules: ROS1 fusions in lung cancer. Lung Cancer. 2019;130:201-207.

4.

Patil T, Smith DE, Bunn PA Jr, et al. The Incidence of Brain Metastases in Stage IV ROS1-Rearranged Non-Small Cell Lung Cancer and Rate of Central Nervous System Progression on Crizotinib. J Thorac Oncol. 2018;13(11):1717-1726.

5.

Gainor JF, Tseng D, Yoda S, et al. Patterns of Metastatic Spread and Mechanisms of Resistance to Crizotinib in ROS1-Positive Non-Small-Cell Lung Cancer. JCO Precis Oncol. 2017;2017:PO.17.00063.

6.

Drilon A, Somwar R, Wagner JP, et al. A Novel Crizotinib-Resistant Solvent-Front Mutation Responsive to Cabozantinib Therapy in a Patient with ROS1-Rearranged Lung Cancer. Cancer Discov. 2017;7(4):400-409.

7.

GSK press release issued 15 July 2026: GSK completes acquisition of Nuvalent, Inc.

8.

Jideytro (zidesamtinib) US Prescribing Information.

Memorial Sloan Kettering Cancer Center Disclosure: Dr. Drilon has financial interests related to Nuvalent, Inc.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorised.

GSK plc

(Registrant)

Date: September 14, 2026

By:/s/ VICTORIA WHYTE

--------------------------

Victoria Whyte

Authorised Signatory for and on

behalf of GSK plc