Loading
Blocking the immune brake CTLA-4 was the first treatment ever to prolong life in metastatic melanoma, with about one in five patients alive at two years and a new class of autoimmune side effects.
This phase 3 trial randomised 676 patients with previously treated, HLA-A*0201-positive metastatic melanoma in a 3:1:1 ratio to ipilimumab plus a gp100 peptide vaccine, ipilimumab alone, or gp100 alone. The primary endpoint was overall survival. Median OS was 10.0 months with ipilimumab plus gp100 and 10.1 months with ipilimumab alone versus 6.4 months with gp100 (hazard ratios 0.68 and 0.66), with survival curves showing a durable tail. Grade 3-4 immune-related adverse events occurred in 10-15% of ipilimumab-treated patients, and 14 deaths were related to study drugs, 7 from immune-related events. It led to FDA approval in March 2011 and validated James Allison's checkpoint-blockade hypothesis in humans.
This paper launched the immunotherapy era. It was the first randomised evidence that taking a brake off the immune system could extend life in a solid cancer, and it introduced clinicians to immune-related adverse events and to responses that arrive late or after apparent progression. Ipilimumab alone has since been superseded by PD-1 antibodies and combinations, but every checkpoint programme traces back to this result.
For patients with advanced melanoma, immunotherapy offers a realistic chance of long-term survival and probably cure, and the ten-year data show that patients who are alive and progression-free at three years rarely die of melanoma afterwards. Nivolumab plus ipilimumab gives the best long-term results but at a high price in serious side effects; nivolumab alone or nivolumab plus relatlimab are alternatives for patients at lower risk or with autoimmune concerns. The trial is also a caution about surrogate endpoints: the survival plateau took years to become visible.
Checkpoint inhibitors are now given to hundreds of thousands of patients a year, many in community clinics and emergency departments, so a common, explicit playbook for their autoimmune side effects saves lives. The guideline standardised when to stop, when to give steroids and when to escalate, and made multidisciplinary toxicity teams routine. It does not remove the judgement needed for rare events or for patients whose cancer is responding.
This trial settled which checkpoint to block first in melanoma and set the pattern for PD-1 antibodies displacing ipilimumab across cancers. Long-term follow-up later showed that many responders remained free of progression years after stopping treatment.
This is the most cited map of the immunotherapy revolution and a good first read before the trials. Its predictions largely held: PD-1 pathway antibodies became the most widely used cancer drugs, PD-L1 testing entered practice, and LAG-3 blockade was approved in melanoma a decade later.
This study is why PD-1 inhibitors were developed across cancers rather than in melanoma alone: unexpected activity in lung cancer, historically thought immune-resistant, changed drug development priorities industry-wide. It also introduced PD-L1 immunohistochemistry as a candidate biomarker and pneumonitis as a signature toxicity. Within five years PD-1 blockade was approved in more than ten cancers.
Shares Padmanee Sharma, James P. Allison, CTLA-4, No one can predict who responds to immunotherapy.
Shares James P. Allison, CTLA-4, No one can predict who responds to immunotherapy, Ipilimumab.
Shares F. Stephen Hodi, Jedd D. Wolchok, Treat the draining lymph node before removing it, CheckMate 067 at ten years: nivolumab plus ipilimumab produces long-term survival in half of patients with advanced melanoma.
Shares Jedd D. Wolchok, Pardoll 2012: the blockade of immune checkpoints in cancer immunotherapy, Immune-related adverse events (irAEs), CTLA-4.
Shares Immune-related adverse events (irAEs), Overall survival (OS), No one can predict who responds to immunotherapy, Bristol Myers Squibb.
Shares KEYNOTE-006 (Robert 2015): pembrolizumab versus ipilimumab in advanced melanoma, CTLA-4, Ipilimumab, Melanoma.
Shares ASCO 2021 guideline: how to recognise and manage the immune-related side effects of checkpoint inhibitors, CTLA-4, Ipilimumab, Melanoma.
Shares Immune-related adverse events (irAEs), No one can predict who responds to immunotherapy, Ipilimumab, Toxicity and quality of life are undervalued.