- Clinical study data shows that patients who receive immunotherapy drug pembrolizumab to treat rare pregnancy cancer show high remission rates.
- Gestational Trophoblastic Disease (GTD) is a broad term to define abnormal cells or tumors in the womb cells that form the placenta.
- Effects of pembrolizumab on fertility need to be determined to assess if it can be offered to women at an earlier stage of treatment.
Immunotherapy drug, pembrolizumab, shows promise in the primary clinical trials in treating women with a rare pregnancy cancer. Three out of four patients who were administered pembrolizumab for gestational trophoblastic disease (GTD) achieved complete remission from the disease. The study findings are published in The Lancet. The research team from Imperial College London suggest that this immunotherapeutic drug could be another treatment option for women who have drug-resistant GTD.
Gestational Trophoblastic Disease (GTD)
GTD is a broad term to describe abnormal cells or tumors that arise in the womb cells that normally give rise to the placenta. Although extremely rare, these occur during or after pregnancy. The most common type is the molar pregnancy
where the fetus cannot develop in the womb but forms abnormal placenta like tissues. While this can be easily removed through a surgery, portions of the tumor may stay behind and lead to metastasis.
180,00 women globally are diagnosed with cancerous forms of GTD that require either surgery or chemotherapy to treat. However, there are women in the five percent group that are either resistant to chemotherapy or have cancers like placental site trophoblastic tumors (PSTT) that develop years after the causative pregnancy has ended.
The trial was aimed to determine the efficacy and remission rates of an immunotherapeutic drug Pembrolizumab
in treating women with multi-drug resistant cancerous GTD. The study carried out at Charing Cross Hospital, part of Imperial College Healthcare NHS Trust, is the first to show that pembrolizumab can be used to successfully treat women with GTD.
‘High remission rates observed in patients who received immunotherapy drug pembrolizumab used to treat gestational trophoblastic disease.’
Four participants aged between 37 to 47 years were given pembrolizumab intravenously every three weeks over a six month period between 2015 and 2017. Following this the pregnancy hormone hCG was measured in the blood. hCG is an indicator letting us know if there are any cancerous placental cells in the womb or other body parts.
The research team found that for most patients hCG levels started to fall by three doses. Once the hCG was normal, five consolidation doses of pembrolizumab were given before stopping treatment. Pembrolizumab was well tolerated by GTD patients and did not cause problems like nausea, vomiting and hair loss that are commonly observed with chemotherapy
"We have been able to show for the first time that immunotherapy may be used to cure patients with cancerous GTD. The current treatments to tackle GTD cure most cases of the disease. However, there are a small number of women whose cancers are resistant to conventional therapies and as a result have a fatal outcome. Immunotherapy may be a life-saving treatment and can be used as an alternative to the much more toxic high dose chemotherapy that is currently used. These are landmark findings that have implications on how we treat the disease in the UK and around the world," Michael Seckl, lead author of the study said.
The cost factor
Pembrolizumab costs Ģ30,000 per patient compared to Ģ70,000 for two rounds of high dose chemotherapy that is used as the standard treatment.
Melody Ransome was one of the participants who took part in the clinical trial after being diagnosed with choriocarcinoma
. The cancer had spread from her uterus to her liver, kidney, pancreas, lungs and brain. Melody received pembrolizumab over five months in 2015. After the second infusion, Melody's hCG levels dropped by 50% and she achieved remission two months later and that continues even now, 2 years after receiving the immunotherapy.
This is what Melody had to say about her treatment:
"Before the trial I was being treated by high dosage of chemotherapy which made me feel awful. I experienced hair loss, fatigue and it was difficult to carry out normal tasks like looking after my two children. On top of that, the chemotherapy wasn't working. This all changed for me once I was given the immunotherapy drug. Each week I felt better and better. I had no side effects and I started to feel more normal. When I was told that I was in remission I was shocked that the treatment had worked in such a short amount of time." References:
- Michael J Seckl et al. Pembrolizumab is effective for drug-resistant gestational trophoblastic neoplasia. The Lancet, November 2017 DOI: 10.1016/S0140-6736(17)32894-5