Advanced Malignant Pleural MesotheliomaPhase 1MESO-PRIMENCT04166734
Pembrolizumab and Hypofractionated Stereotactic Radiotherapy in Patients With Malignant Pleural Mesothelioma
A Phase 1 study testing Pembrolizumab and Stereotactic Body Radiotherapy (SBRT) in people with Advanced Malignant Pleural Mesothelioma, run by Royal Marsden NHS Foundation Trust at 2 sites in United Kingdom.
Trial summary
This is a multi-centre non-randomised open-label phase 1 trial of pembrolizumab given in combination with SBRT to part of a pleural-based lesion in patients with unresectable MPM. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Advanced Malignant Pleural Mesothelioma
- What is being tested?
- Pembrolizumab and Stereotactic Body Radiotherapy (SBRT)
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 5 participants
- Where
- 2 sitesUnited Kingdom
- Study dates
- 12 Feb 2021to 25 Jul 2023
- Phase
- Phase 1
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients should be ≥18 years old on the day of signing the informed consent.
- Patients must have a histological or cytological diagnosis of MPM.
- Patients should have non-radically treatable MPM (i.e. not being considered for extrapleural pneumonectomy or pleurectomy and decortication).
- Patients must have measurable disease as assessed by mRECIST (i.e. at least a 1 cm rind of MPM at 2 sites on 3 different levels).
- Patients must have had disease progression or be intolerant of standard first-line palliative chemotherapy for MPM. Patients who have declined first-line palliative chemotherapy must have been suitable for platinum-doublet combination chemotherapy.
- Patient should have an ECOG performance status 0-1.
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- Patients should be able to tolerate a course of stereotactic radiotherapy as assessed by the investigator.
- Patients should have pleural based disease, away from critical structures, and suitable for treatment to part of lesion with SBRT for pleural mesothelioma.
- Patients must have adequate organ function including MRC dyspnoea score <3 and adequate baseline lung function tests, with an FEV1 > 0.8L or >30% of predicted and a TLCO > 30%.
- Demonstrate adequate organ function (based on bloods within 10 days of C1D1).
- Have provided tissue from an archival tissue sample or newly obtained tissue sample.
- Female patient of childbearing potential should have a negative serum pregnancy within 72 hours prior to receiving the first dose of study medication (C1D1). Female patients of childbearing potential should be willing to use highly effective methods of contraception for the course of the study through 120 days after the last dose of study medication. Female of childbearing potential is defined as women following menarche and until becoming post-menopausal unless permanently sterile. Permanent sterilisation methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy. A postmenopausal state is defined as no menses for 12 months without an alternative medical cause.
- Male patients should agree to use an adequate method of contraception starting with the first dose of study therapy through 120 days after the last dose of study therapy.
- Be willing to provide informed consent for the trial.
Who cannot join
- Patients who have taken any investigational medicinal product or have used an investigational device within 4 weeks of the first dose of pembrolizumab. Patients are allowed to participate in additional observational studies.
- Patients who have received prior chemotherapy, targeted small molecule therapy or radiotherapy within 4 weeks prior to the first dose of pembrolizumab.
- Patients with a diagnosis of immunodeficiency or be receiving systemic steroid therapy (>7.5 mg of prednisone / >1 mg of dexamethasone or their equivalent dose) or any other form of immunosuppressive therapy within 7 days prior to the first dose.
- Patients with evidence of active autoimmune disease requiring systemic treatment within the past 3 months or a documented history of clinically severe autoimmune disease, or a syndrome that requires systemic steroids or immunosuppressive agents or an autoimmune disease that is currently quiescent off any treatment, but deemed at risk of a significant flare if treated on this protocol.
- Patients who have received prior therapy with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137, or anti-Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) antibody (including ipilimumab or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways).
- Patients with evidence of active central nervous system (CNS) metastases and/or carcinomatous meningitis. Patients with previously treated brain metastases may participate provided the brain metastases are stable and there is no evidence of new or enlarging brain metastases.
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- Patients who have had previous radiotherapy to the thorax or other neighbouring region that would preclude the safe administration of SBRT for MPM.
- Patients with evidence of interstitial lung disease or active, non-infectious pneumonitis.
- Patients with evidence of additional malignancy that is progressing or requires active treatment.
- Patients with a history or current evidence of any condition, therapy, or laboratory abnormality that might confound trial results, interfere with the patient's participation or is not in the best interest of the patient.
- Patients with psychiatric or substance abuse disorders that would interfere with patients participation.
- Patients who are pregnant / breastfeeding or expecting to conceive within the duration of the trial, starting with the screening visit through 120 days after the last dose.
- Patients with a history of HIV, HIV 1/2 antibodies, Hepatitis B or Hepatitis C.
- Patients with any active infection requiring systemic treatment
- Patients who have received a live vaccine within 30 days prior to the first dose of trial treatment.
- Patients with known hypersensitivity to the active substance pembrolizumab or to any of the excipients listed in the IB.
Trial locations and contacts
2 sites in 1 country.
United Kingdom2 sites
Royal Marsden NHS Foundation Trust
Chelsea
Beatson West of Scotland Cancer Centre
Glasgow, G12 0YN
About this study
This is a multi-centre non-randomised open-label phase 1 trial of pembrolizumab given in combination with SBRT to part of a pleural-based lesion in patients with unresectable MPM. This study will recruit up to 18 patients whose MPM has progressed beyond first-line of palliative chemotherapy, with a platinum-based doublet, and now requires further palliative systemic treatment, or have declined first-line palliative chemotherapy, however must have been considered suitable for a platinum doublet chemotherapy.
Read the detailed description
The study will be conducted in two parts; an initial safety phase (Part A), followed by an expansion cohort (Part B). The initial safety phase (Part A) is based on a 3+3 design such that patients will be treated in a cohort of 3-6 patients. A maximum of 6 patients will be allocated to Part A exploring SBRT 30 Gy in 3 fractions in combination with pembrolizumab. If there is more than one DLT in the first 3 patients or two or more DLTs in the first 6 patients, this treatment combination will be deemed as being unacceptable and it would lead to termination of the study. During the expansion cohort (Part B), 12 patients will have SBRT 30 Gy in 3 fractions with pembrolizumab to obtain additional safety and response data. Maintenance pembrolizumab will continue until disease progression, unacceptable toxicities, the patient withdraws consent to the trial, or the patient has completed 35 cycles of treatment. A maximum of 18 patients will be treated in the study.
All patients will receive pembrolizumab on cycle (C) 1 day (D) 1, in Part A and B of the study. All patients will receive SBRT on C1D15, C1D17 and C1D19, as per SBRT protocol. Patients in part A will receive SBRT 30 Gy in 3#. Patients in Part B will receive 30 Gy in 3 fractions if considered safe after part A. All patients in Part A and Part B will receive pembrolizumab dosed at 200 mg every 3 weeks, until disease progression, unacceptable toxicities, the patient withdraws consent from the trial or the patient has completed 35 cycles of treatment.
In the initial safety cohort, a minimum of 3 patients will be treated at the SBRT dose of 30Gy in 3 fractions combined with pembrolizumab. The gap left between the treatments of each subsequent patient will start after the second cycle of Pembrolizumab in the previous dosed patient to mitigate against multiple patients suffering from acute toxicity. The DLT period for this study is 12 weeks from the last dose of SBRT (i.e. at C6D1). Patients included in Part A will be considered by the Safety Review Committee (SRC) once the 3rd and 6th patient in the Part A cohort has completed the DLT period. If 0 out of 3 patients experience a DLT, or if 1 out of 3 patients experience a DLT in Part A, then the cohort will be expanded to 6 patients. If 1 in 6 patients experience a DLT, then it will be acceptable to move forward to the expansion cohort (Part B).
However, if ≥ 2 in 6 patients (or more than 1 in the first 3 patients) experience a DLT then the maximum administered dose (MAD) will have been reached. If the MAD is seen at a dose level of 30 Gy in 3# then the study will be terminated.
While waiting for 3 or 6 patients to complete the DLT period, no additional patients will be recruited. Further patients can only be recruited after the SRC has reviewed the toxicity data for the cohort to proceed to Part B. Patients obtaining complete response or having completed 35 cycles of pembrolizumab must discontinue and may recommence for additional 17 cycles upon subsequent disease, the CI/PI will need to discuss with the sponsor and MSD, on a case by case basis for the continuation of pembrolizumab
- Conditions
- Advanced Malignant Pleural Mesothelioma
- Being tested
- Pembrolizumab, Stereotactic Body Radiotherapy (SBRT)
- Keywords
- Advanced malignant pleural mesothelioma, mesothelioma, pembrolizumab, radiotherapy, SBRT, External Beam Stereotactic Body Radiotherapy
- Medical subject headings
- Mesothelioma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PembrolizumabDrug
Also called Keytruda
Pembrolizumab will be continued dosed at 200 mg given every 3 weeks
Drug: Pembrolizumab Pembrolizumab in week 1 dosed at 200 mg (prior to SBRT) and then treatment with pembrolizumab will be continued dosed at 200 mg given every 3 weeks.
Stereotactic Body Radiotherapy (SBRT)Radiation
Also called SBRT
Stereotactic Body Radiotherapy (SBRT) 30 Gy 3 fractions (#)
| Study group | Role | What they receive |
|---|---|---|
| Initial safety cohort | Other | Patients will receive an initial dose of pembrolizumab in week 1 dosed at 200 mg. They will then receive SBRT dosed at 30 Gy in 3 fractions (#) alternate days in week 3. Treatment with pembrolizumab will be continued dosed at 200 mg given every 3 weeks. Receives: Drug: Pembrolizumab; Radiation: Stereotactic Body Radiotherapy (SBRT) |
| Expansion cohort | Other | An additional 12 patients will be recruited for this cohort. Patients will receive an initial dose of pembrolizumab at 200 mg in week 1. This will be followed in by SBRT dosed at 30 Gy in 3 fractions (#) alternate days in week 3. Treatment with pembrolizumab will be continued dosed at 200 mg given every 3 weeks. Receives: Drug: Pembrolizumab; Radiation: Stereotactic Body Radiotherapy (SBRT) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of Patients With Dose Limiting Toxicity (DLT)
Dose limiting toxicity is assessed using CTCAE v5.0 and defined as any one of: neutropenia with fever grade>=3; neutropenia grade>=4; thrombocytopenia with bleeding grade >=3; thrombocytopenia grade >=4; any non-haematological toxicity grade >=3 which is definitely, probably or possibly related to the combination of pembrolizumab and SBRT
Measured: Worst grade as assessed at cycle 1 day 1 of pembrolizumab, at each of three radiotherapy fractions (cycle 1 days 15, 17, 19) and then at day 1 of each 21 day cycle, up to 12 weeks from last dose of SBRT (i.e. cycle 6 day 1)
Secondary outcomes (7)
Worst Acute Toxicity Grade
Number of patients by worst recorded grade of acute toxicity, assessed using CTCAE v5.0
Measured: Worst grade as assessed at cycle 1 day 1 of pembrolizumab, at each of three radiotherapy fractions (cycle 1 days 15, 17, 19) and then at day 1 of each 21 day cycle, up to 12 weeks from last dose of SBRT (i.e. cycle 6 day 1)
Overall Response Rate
Proportion of patients with best recorded response as assessed using RECIST v1.1 of complete or partial response
Measured: Response assessed from start of pembrolizumab, every 9 weeks for the first 6 months, then every 12 weeks thereafter, until the first instance of documented disease progression, start of new anti-cancer treatment, death or end of study (24 months)
Disease Control Rate
Proportion of patients with best recorded response as assessed using RECIST v1.1 of complete or partial response or stable disease
Measured: Response assessed from start of pembrolizumab, every 9 weeks for the first 6 months, then every 12 weeks thereafter, until the first instance of documented disease progression, start of new anti-cancer treatment, death or end of study (24 months)
Overall Survival (OS) at Six Months
Proportion of patients alive at six months
Measured: 6 months after start of pembrolizumab treatment
Overall Survival (OS) at Twelve Months
Proportion of patients alive at twelve months
Measured: 12 months after start of pembrolizumab treatment
Progression Free Survival at 6 Months
Proportion of patients alive and free from progression at six months
Measured: 6 months after commencing pembrolizumab treatment
Progression Free Survival at 12 Months
Proportion of patients alive and free from progression at twelve months
Measured: 12 months after commencing pembrolizumab treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Nov 2019
- Study start12 Feb 2021
- Primary completion25 Jul 2023
- Study completion25 Jul 2023
Why it stopped: Study terminated due to slow recruitment and insufficient further funding.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Advanced Malignant Pleural MesotheliomaStudies of the same condition, open and under way.
- More trials run by Royal Marsden NHS Foundation TrustThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Model description
- Initial safety phase followed by an Expansion phase
- Masking
- None (open label)
- Enrolment
- 5 participants (actual)
Sponsor and investigators
- Lead sponsor
- Royal Marsden NHS Foundation Trust
- Sponsor type
- University, hospital or other
- Collaborators
- Merck Sharp & Dohme LLC
- Responsible party
- Sponsor
- Investigators
- Fiona McDonald, Study chair, Royal Marsden NHS Foundation Trust
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04166734
- Sponsor's protocol ID
- CCR4583
- Acronym
- MESO-PRIME
- Status last verified
- Feb 2026
- First submitted
- 8 Nov 2019
- Last updated
- 4 Feb 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pembrolizumab and Hypofractionated Stereotactic Radiotherapy in Patients With Malignant Pleural Mesothelioma
- ClinicalTrials.gov ID
- NCT04166734
- Acronym / sponsor ID
- MESO-PRIME / CCR4583
- Conditions
- Advanced Malignant Pleural Mesothelioma
- Keywords
- Advanced malignant pleural mesothelioma, mesothelioma, pembrolizumab, radiotherapy, SBRT, External Beam Stereotactic Body Radiotherapy
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Study terminated due to slow recruitment and insufficient further funding.
- Enrolment
- 5 participants (actual)
- Lead sponsor
- Royal Marsden NHS Foundation TrustUniversity, hospital or other
- Collaborators
- Merck Sharp & Dohme LLC
- Study start
- 12 Feb 2021 (actual)
- Primary completion
- 25 Jul 2023 (actual)
- Study completion
- 25 Jul 2023 (actual)
- First posted
- 18 Nov 2019 (actual)
- Results
- Posted 4 Feb 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a multi-centre non-randomised open-label phase 1 trial of pembrolizumab given in combination with SBRT to part of a pleural-based lesion in patients with unresectable MPM. This study will recruit up to 18 patients whose MPM has progressed beyond first-line of palliative chemotherapy, with a platinum-based doublet, and now requires further palliative systemic treatment, or have declined first-line palliative chemotherapy, however must have been considered suitable for a platinum doublet chemotherapy.
Detailed description
The study will be conducted in two parts; an initial safety phase (Part A), followed by an expansion cohort (Part B). The initial safety phase (Part A) is based on a 3+3 design such that patients will be treated in a cohort of 3-6 patients. A maximum of 6 patients will be allocated to Part A exploring SBRT 30 Gy in 3 fractions in combination with pembrolizumab. If there is more than one DLT in the first 3 patients or two or more DLTs in the first 6 patients, this treatment combination will be deemed as being unacceptable and it would lead to termination of the study. During the expansion cohort (Part B), 12 patients will have SBRT 30 Gy in 3 fractions with pembrolizumab to obtain additional safety and response data. Maintenance pembrolizumab will continue until disease progression, unacceptable toxicities, the patient withdraws consent to the trial, or the patient has completed 35 cycles of treatment. A maximum of 18 patients will be treated in the study.
All patients will receive pembrolizumab on cycle (C) 1 day (D) 1, in Part A and B of the study. All patients will receive SBRT on C1D15, C1D17 and C1D19, as per SBRT protocol. Patients in part A will receive SBRT 30 Gy in 3#. Patients in Part B will receive 30 Gy in 3 fractions if considered safe after part A. All patients in Part A and Part B will receive pembrolizumab dosed at 200 mg every 3 weeks, until disease progression, unacceptable toxicities, the patient withdraws consent from the trial or the patient has completed 35 cycles of treatment.
In the initial safety cohort, a minimum of 3 patients will be treated at the SBRT dose of 30Gy in 3 fractions combined with pembrolizumab. The gap left between the treatments of each subsequent patient will start after the second cycle of Pembrolizumab in the previous dosed patient to mitigate against multiple patients suffering from acute toxicity. The DLT period for this study is 12 weeks from the last dose of SBRT (i.e. at C6D1). Patients included in Part A will be considered by the Safety Review Committee (SRC) once the 3rd and 6th patient in the Part A cohort has completed the DLT period. If 0 out of 3 patients experience a DLT, or if 1 out of 3 patients experience a DLT in Part A, then the cohort will be expanded to 6 patients. If 1 in 6 patients experience a DLT, then it will be acceptable to move forward to the expansion cohort (Part B).
However, if ≥ 2 in 6 patients (or more than 1 in the first 3 patients) experience a DLT then the maximum administered dose (MAD) will have been reached. If the MAD is seen at a dose level of 30 Gy in 3# then the study will be terminated.
While waiting for 3 or 6 patients to complete the DLT period, no additional patients will be recruited. Further patients can only be recruited after the SRC has reviewed the toxicity data for the cohort to proceed to Part B. Patients obtaining complete response or having completed 35 cycles of pembrolizumab must discontinue and may recommence for additional 17 cycles upon subsequent disease, the CI/PI will need to discuss with the sponsor and MSD, on a case by case basis for the continuation of pembrolizumab
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Initial safety phase followed by an Expansion phase
| Arm | Type | Receives |
|---|---|---|
| Initial safety cohort | Other | Drug: Pembrolizumab, Radiation: Stereotactic Body Radiotherapy (SBRT)Patients will receive an initial dose of pembrolizumab in week 1 dosed at 200 mg. They will then receive SBRT dosed at 30 Gy in 3 fractions (#) alternate days in week 3. Treatment with pembrolizumab will be continued dosed at 200 mg given every 3 weeks. |
| Expansion cohort | Other | Drug: Pembrolizumab, Radiation: Stereotactic Body Radiotherapy (SBRT)An additional 12 patients will be recruited for this cohort. Patients will receive an initial dose of pembrolizumab at 200 mg in week 1. This will be followed in by SBRT dosed at 30 Gy in 3 fractions (#) alternate days in week 3. Treatment with pembrolizumab will be continued dosed at 200 mg given every 3 weeks. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (14 listed)
- Patients should be ≥18 years old on the day of signing the informed consent.
- Patients must have a histological or cytological diagnosis of MPM.
- Patients should have non-radically treatable MPM (i.e. not being considered for extrapleural pneumonectomy or pleurectomy and decortication).
- Patients must have measurable disease as assessed by mRECIST (i.e. at least a 1 cm rind of MPM at 2 sites on 3 different levels).
- Patients must have had disease progression or be intolerant of standard first-line palliative chemotherapy for MPM. Patients who have declined first-line palliative chemotherapy must have been suitable for platinum-doublet combination chemotherapy.
Key exclusion criteria (16 listed)
- Patients who have taken any investigational medicinal product or have used an investigational device within 4 weeks of the first dose of pembrolizumab. Patients are allowed to participate in additional observational studies.
- Patients who have received prior chemotherapy, targeted small molecule therapy or radiotherapy within 4 weeks prior to the first dose of pembrolizumab.
- Patients with a diagnosis of immunodeficiency or be receiving systemic steroid therapy (>7.5 mg of prednisone / >1 mg of dexamethasone or their equivalent dose) or any other form of immunosuppressive therapy within 7 days prior to the first dose.
- Patients with evidence of active autoimmune disease requiring systemic treatment within the past 3 months or a documented history of clinically severe autoimmune disease, or a syndrome that requires systemic steroids or immunosuppressive agents or an autoimmune disease that is currently quiescent off any treatment, but deemed at risk of a significant flare if treated on this protocol.
- Patients who have received prior therapy with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137, or anti-Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) antibody (including ipilimumab or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| PembrolizumabAlso: KeytrudaPembrolizumab will be continued dosed at 200 mg given every 3 weeks Drug: Pembrolizumab Pembrolizumab in week 1 dosed at 200 mg (prior to SBRT) and then treatment with pembrolizumab will be continued dosed at 200 mg given every 3 weeks. | Drug | Expansion cohort, Initial safety cohort |
| Stereotactic Body Radiotherapy (SBRT)Also: SBRTStereotactic Body Radiotherapy (SBRT) 30 Gy 3 fractions (#) | Radiation | Expansion cohort, Initial safety cohort |
Primary outcome
Percentage of Patients With Dose Limiting Toxicity (DLT)
Time frame: Worst grade as assessed at cycle 1 day 1 of pembrolizumab, at each of three radiotherapy fractions (cycle 1 days 15, 17, 19) and then at day 1 of each 21 day cycle, up to 12 weeks from last dose of SBRT (i.e. cycle 6 day 1)
Dose limiting toxicity is assessed using CTCAE v5.0 and defined as any one of: neutropenia with fever grade>=3; neutropenia grade>=4; thrombocytopenia with bleeding grade >=3; thrombocytopenia grade >=4; any non-haematological toxicity grade >=3 which is definitely, probably or possibly related to the combination of pembrolizumab and SBRT
7 secondary outcomes
Worst Acute Toxicity Grade
Time frame: Worst grade as assessed at cycle 1 day 1 of pembrolizumab, at each of three radiotherapy fractions (cycle 1 days 15, 17, 19) and then at day 1 of each 21 day cycle, up to 12 weeks from last dose of SBRT (i.e. cycle 6 day 1)
Overall Response Rate
Time frame: Response assessed from start of pembrolizumab, every 9 weeks for the first 6 months, then every 12 weeks thereafter, until the first instance of documented disease progression, start of new anti-cancer treatment, death or end of study (24 months)
Disease Control Rate
Time frame: Response assessed from start of pembrolizumab, every 9 weeks for the first 6 months, then every 12 weeks thereafter, until the first instance of documented disease progression, start of new anti-cancer treatment, death or end of study (24 months)
Overall Survival (OS) at Six Months
Time frame: 6 months after start of pembrolizumab treatment
Overall Survival (OS) at Twelve Months
Time frame: 12 months after start of pembrolizumab treatment
Progression Free Survival at 6 Months
Time frame: 6 months after commencing pembrolizumab treatment
Progression Free Survival at 12 Months
Time frame: 12 months after commencing pembrolizumab treatment
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Feb 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Fiona McDonald study chair
Royal Marsden NHS Foundation Trust
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Pembrolizumab and Stereotactic Body Radiotherapy (SBRT) in people with Advanced Malignant Pleural Mesothelioma, run by Royal Marsden NHS Foundation Trust at 2 sites in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 14 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 4 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 4 Feb 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of Patients With Dose Limiting Toxicity (DLT) (time frame: Worst grade as assessed at cycle 1 day 1 of pembrolizumab, at each of three radiotherapy fractions (cycle 1 days 15, 17, 19) and then at day 1 of each 21 day cycle, up to 12 weeks from last dose of SBRT (i.e. cycle 6 day 1)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Feb 2026.