NCT03430700

Who might be able to join this trial:

• You have been diagnosed with high-grade recurrent ovarian cancer, fallopian tube cancer, or primary peritoneal cancer (not the mucinous type)
• You are 18 years of age or older
• You are willing and able to sign a consent form showing you understand the study, its risks and benefits, and what it involves
• You have received at least 4 cycles of weekly paclitaxel (a chemotherapy drug) for your recurring cancer, given because further platinum-based chemotherapy was not considered suitable
• You have had no more than 3 previous rounds of platinum-based chemotherapy for ovarian cancer before starting weekly paclitaxel
• Your cancer has at least stayed stable (not grown) or improved after at least 4 cycles of weekly paclitaxel, confirmed by a CT or MRI scan
• You are able to start the trial treatment (pembrolizumab) within 8 weeks of your last paclitaxel dose
• A stored sample of your tumour tissue is available from a previous biopsy
• You are willing to have a fresh tumour biopsy taken at the start of the trial if it is considered safe and technically possible to do so, and a second biopsy before cycle 4 if also feasible
• You are in good general health and able to carry out most normal daily activities (confirm with trial site — this is based on a standard medical fitness scale scoring 0 or 1)
• You are willing and able to follow all study procedures, appointments, and follow-up visits for the full duration of the trial
• Your blood tests show that your organs (such as your kidneys, liver, and bone marrow) are working well enough, tested within 10 days of starting treatment
• If you could become pregnant, you have a negative pregnancy test before starting treatment
• If you could become pregnant, you are willing to use a reliable method of contraception from the start of treatment until 4 months after your last dose of the study drug

Who may not be able to join:

• You have previously been treated with certain immunotherapy drugs that target PD-1, PD-L1, PD-L2, CTLA-4, or similar pathways (confirm with trial site if unsure about your previous treatments)
• You have been diagnosed with low-grade or mucinous ovarian cancer
• You have a condition that affects your immune system, or you are currently taking high-dose steroid tablets or other medicines that suppress your immune system (inhaled steroids are generally allowed; confirm with trial site)
• You have a known history of active tuberculosis (TB)
• You have a known history of Hepatitis B or Hepatitis C infection
• You have a known history of HIV
• You have received any other cancer treatment (including experimental treatments) within the past 4 weeks, or you have not yet fully recovered from side effects of previous treatments (minor nerve-related side effects may still be acceptable — confirm with trial site)
• You have had radiotherapy within the past 2 weeks, or you have not recovered from radiation-related side effects
• You have been diagnosed with another cancer in the past 5 years, with some exceptions such as very early-stage womb cancer, cervical cancer in situ, or certain early breast conditions (confirm with trial site)
• You have active cancer that has spread to the brain or the lining around the brain (previously treated brain metastases may be acceptable — confirm with trial site)
• You have an autoimmune disease (where your immune system attacks your own body) that has needed treatment with strong medicines in the past 2 years, with some exceptions such as vitiligo or childhood asthma that has fully resolved
• Your blood calcium level is too high and has not responded to treatment to bring it down
• You have a history of, or currently have, lung inflammation (pneumonitis) or scarring of the lungs (interstitial lung disease) that required steroid treatment
• You have a recently diagnosed blood clot (such as a DVT or pulmonary embolism) that has not yet been treated with blood-thinning medication for at least 14 days, or you have a history of a blood clot in an artery
• You currently have an active infection that requires treatment with medicines given through a drip or by mouth
• You have had symptoms of bowel blockage in the past three months
• You have a serious ongoing medical or mental health condition that, in your