Pembrolizumab

For the first time a new drug has beaten pembrolizumab, the global first-line standard, in a randomised lung cancer trial, and it did so by combining checkpoint blockade with anti-angiogenesis in one molecule. For patients outside China nothing changes yet: the drug is not approved in the West, the trial was single-country, and survival benefit has not been shown. If confirmed in the global HARMONi-3 and HARMONi-7 trials, PD-1 x VEGF bispecifics could replace PD-1 antibodies as the immunotherapy backbone.

Almost every patient newly diagnosed with advanced bladder or urothelial cancer should now be offered enfortumab vedotin plus pembrolizumab rather than chemotherapy, with median survival extended from about 16 months to over two and a half years. Neuropathy and skin toxicity need monitoring and dose adjustment, and patients with severe diabetes or pre-existing neuropathy need care. Platinum chemotherapy remains an option for those who cannot receive the combination.

For the first time a randomised trial suggests that a vaccine tailored to an individual's tumour can reduce relapse when combined with immunotherapy, which is a proof of concept for a field that had failed for decades. Nothing changes for patients yet: the trial was small, the confidence interval crossed one, and the phase 3 trial in melanoma (and parallel trials in lung and other cancers) must confirm it. If it does, personalised mRNA vaccines could become a routine adjunct to checkpoint inhibitors after surgery.

Women with locally advanced cervical cancer that is node-positive or stage III-IVA should now be offered pembrolizumab alongside and after chemoradiotherapy, which improves the chance of cure. The result matters most in countries where cervical cancer is common but immunotherapy access is poorest, so its global impact depends on pricing and health-system capacity. It does not apply to early-stage disease treated with surgery or to lower-risk locally advanced disease without nodal involvement.

Cercek's dostarlimab study is the clearest demonstration that immunotherapy can replace surgery in a solid tumour: patients with dMMR rectal cancer can keep their rectum and avoid the permanent effects of pelvic radiotherapy and surgery. Non-operative management after PD-1 blockade is now in guidelines for this group, and MMR testing before treatment of rectal cancer is essential. The approach applies only to the 5-10% of rectal cancers that are dMMR.

For stage II-III triple-negative breast cancer, chemotherapy plus pembrolizumab before surgery and pembrolizumab alone afterwards is now the standard approach worldwide, and the survival gain is real, not just a surrogate. It does not apply to stage I disease or to hormone-receptor-positive or HER2-positive cancers. The price is a year of immunotherapy with a meaningful chance of a permanent endocrine side effect such as hypothyroidism or adrenal insufficiency.

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.

Patients with newly diagnosed advanced clear-cell kidney cancer should receive an immunotherapy-based combination; lenvatinib plus pembrolizumab gives the highest response rate and longest PFS of the available options, at the cost of more side effects requiring dose adjustment. Sunitinib alone is no longer an appropriate standard. Choosing among the combinations depends on risk group, symptoms, comorbidity and the value placed on treatment-free survival, which favours nivolumab plus ipilimumab in intermediate and poor risk.

Patients whose kidney cancer has been removed but who are at high risk of recurrence (large or high-grade tumours, node involvement, or resected metastases) can now be offered a year of pembrolizumab, which increases the chance of being alive and cancer-free several years later. Roughly nine patients need treatment to prevent one recurrence at two years, and some will have permanent side effects, so shared decision-making matters. Why pembrolizumab succeeded where similar drugs failed is not fully understood.

Every colorectal cancer should be tested for mismatch repair deficiency, because patients whose metastatic tumour is dMMR should receive pembrolizumab rather than chemotherapy as first treatment, gaining a much better chance of durable remission with fewer side effects. About a third of dMMR tumours do not respond initially, so early scans are essential and chemotherapy remains available. The trial does not apply to the 95% of colorectal cancers that are mismatch-repair proficient.

Patients with head and neck squamous cell cancer that has recurred or spread should be treated first with pembrolizumab: alone if their tumour is strongly PD-L1 positive and they can wait for a slower response, or with chemotherapy if the tumour is bulky or PD-L1 low. Cetuximab-based chemotherapy is no longer the default. Long-term follow-up shows a small but real group of patients alive at four to five years, which was almost unheard of before.

Most patients with newly diagnosed advanced non-squamous lung cancer that lacks a targetable mutation should receive chemotherapy plus pembrolizumab; those with PD-L1 of 50% or more may reasonably receive pembrolizumab alone. About one in five patients is alive at five years, compared with roughly one in ten with chemotherapy alone. Patients with EGFR or ALK alterations were excluded and should have targeted therapy first.

This paper established a new regulatory paradigm: a drug approved for a molecular feature regardless of organ. It made MSI/MMR testing standard across advanced cancers and remains the clearest example of a biomarker that works across histologies. It also anchored the idea that mutation load, via neoantigens, is what makes tumours visible to T cells.

This small trial explained why colorectal cancer had seemed immune-resistant (most is MMR-proficient) and established the principle that a genomic feature, not the tissue of origin, can predict immunotherapy response. It led directly to the 2017 tissue-agnostic approval of pembrolizumab and to routine MMR/MSI testing of many cancers. Every patient with advanced dMMR cancer should now be considered for checkpoint blockade.

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.

Tumours hide from T cells by displaying PD-L1; blocking that interaction lets the immune system attack. This is the mechanism of pembrolizumab, nivolumab, atezolizumab and their relatives, which now treat more than 20 cancer types.