Press release posted 29 July 2025
Zara McCormick, a 36-year-old mum and project manager from Gee Cross in Tameside, is celebrating more than 18 months of being free from bowel cancer after taking part in a clinical trial at The Christie NHS Foundation Trust, a specialist cancer centre in Manchester.
The interim results of the NEOPRISM trial show that giving people with microsatellite instability (MSI-H) bowel cancer* like Zara’s an immunotherapy drug called pembrolizumab** instead of chemotherapy before surgery dramatically improved outcomes.
Almost 60% of patients had no signs of cancer after treatment with pembrolizumab alone, with the rest cancer free after subsequent surgery.*** The current standard of care would be surgery, and then possibly conventional chemotherapy which is likely to be less effective than immunotherapy prior to surgery.
Zara, who is married to Paul and is mum to Lewis (3), was diagnosed the same week as Lewis’s first birthday, had initially put her symptoms – anaemia which was causing fatigue and breathlessness – down to pregnancy. However, when they continued after Lewis was born, she went to have some tests at her local hospital and was diagnosed with stage 3c bowel cancer with an MSI-H mutation. This type of cancer is very responsive to immunotherapy, so she was referred to The Christie to find out more about the NEOPRISM trial.
“I didn’t have any of the typical symptoms like blood in my poo, so the diagnosis came as a massive shock. At first, I was quite hesitant about going on a trial, but my team at The Christie really helped to put my mind at ease. They took the time to talk me through everything and answer all my questions. They explained that my type of cancer might not respond to chemotherapy – the standard treatment currently available – and gave me all the information I needed to make the right choice for me. By the end of the appointment, I’d decided to go for it,” says Zara.
Zara started her 3 cycles of pembrolizumab in June 2023. She then had a scan, which showed that the tumours in her bowel and lymph nodes had shrunk significantly, and she had surgery to remove part of her bowel. She had the operation at The Christie in September, and the subsequent biopsy result showed there were no active cancer cells, only scar tissue, so she’d had a complete response to her treatment.
Zara remains cancer-free and now has 6-monthly scans and yearly colonoscopies at The Christie.
Of her experience, she says: “Although I tolerated the treatment well, it did leave me feeling fatigued, so I’m really focused on getting my fitness back so I can be as active as my little boy is. I’m back at work and looking forward to the little things, like celebrating my 10th wedding anniversary in a couple of years and seeing Lewis start school. I’m also involved in some bowel cancer support groups, helping others like me.
“I was so well looked after by my team at The Christie, I can’t thank them enough for what they’ve done for me. Anup, my nurse, was particularly brilliant. He was the first person I spoke to at my first appointment and has been there for me every step of the way. Having someone like that there when you’re going through a difficult time makes all the difference.
“One of the reasons I wanted to share my story is to change the perception that clinical trials are a last resort. For me, this was the first treatment I had, and I’m so glad I said yes. I would encourage other people with cancer to be open-minded about taking part. New treatments wouldn’t be possible without trials, so you’re also helping make things better for other people in the future. There’s something very special about that.”
Professor Mark Saunders, Zara’s consultant oncologist at The Christie, comments: “It’s brilliant to see that Zara and all the other patients have responded so well to immunotherapy. More trials need to be done to validate the findings, but the results we’ve seen so far are really encouraging. Pembrolizumab is a very effective drug and has the potential to change the lives of a few thousand people diagnosed with this type of bowel cancer in the UK every year.”
The NEOPRISM trial is still recruiting patients, and over the next few years, researchers will assess overall survival and relapse rates. NEOPRISM is a collaboration between UCL (University College London), UCLH, The Christie, St. James’s University Hospital in Leeds, University Hospital Southampton, and the University of Glasgow.
It is led and sponsored by University College London (UCL) with funding from pharmaceutical company Merck, Sharp and Dohme, and is being conducted by the CRUK and UCL Cancer Trials Centre.
The target recruitment is 78 people, and the team hope to complete recruitment as soon as possible.
When patients are referred to The Christie to discuss their cancer treatment, details regarding potential clinical trials they may be suitable for will be discussed. Together, the patient and clinical team will decide whether it is appropriate to proceed with a trial or not. More information about taking part in clinical trials can be found on our taking part in studies and trials page.
*This type of cancer occurs when mismatch repair (MMR) genes, whose job is to correct errors that happen during cell division, stop functioning properly. Around 10-15% people with bowel cancer have this mutation.
** Immunotherapy works by stimulating the body’s immune system to identify and fight cancer. Pembrolizumab is a type of targeted therapy drug called an immune checkpoint inhibitor (a type of immunotherapy). It works by keeping cancer cells from suppressing the immune system. This allows the immune system to attack and kill the cancer cells. It is currently approved for us in the UK for a wide range of cancers including breast cancer, melanoma, cervical cancer and some types of lymphomas and carcinomas.