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How long does it take for Keytruda to work?

Medically reviewed by Nicole France, BPharm. Last updated on Sep 9, 2021.

Official answer


Keytruda (pembrolizumab) is a programmed death receptor-1 (PD-1)-blocking monoclonal antibody used to treat a number of different types of cancer. Keytruda is administered via a 30 min intravenous (IV) infusion every 3-6 weeks. A response to treatment is typically seen within 2-4 months of starting treatment with Keytruda, but the time it takes to work will vary based on cancer type and the stage of disease.

Keytruda is a type of immunotherapy that works by preventing cancer cells from hiding from your immune system. Immunotherapy works differently to traditional chemotherapy drugs - it takes time for the immune system to identify and attack cancer cells once Keytruda helps prevent the cancer cells from hiding.

When determining how long Keutruda takes to work, researchers measure the ‘time to response’, which gives the time frame in which you’d expect to see a patient’s cancer show signs that it is responding to treatment.

‘Time to response’ is the time taken from the day a patient is assigned to receive a particular therapy until the first day that the patient has a partial or complete response to the treatment. The ‘time to response’ observed in a number of clinical trials used to gain approval of Keytruda are reported in the table below.

Time to response following treatment with Keytruda

Cancer Type
(Trial name)
Median Time to Response
Keytruda: 85-86 days (range 32-251)
Yervoy (ipilimumab): 87 days (range 80-250)
Keytruda: 13-15 weeks (IQR 12-18)
Investigator-choice (paclitaxel plus carboplatin, paclitaxel, carboplatin, dacarbazine, or oral temozolomide): 13 weeks (12-18)
Non-small cell lung cancer
Keytruda + pemetrexed + cisplatin or carboplatin: 1.4 months (1.2-3.0)
Placebo + Alimta (pemetrexed) + cisplatin or carboplatin: 1.4 months (1.2-4.9)
Non-small cell lung cancer
Keytruda + carboplatin + paclitaxel or Abraxane (nanoparticle albumin-bound paclitaxel): 1.4 months
Placebo + carboplatin + paclitaxel or Abraxane: 1.4 months
Non-small cell lung cancer
Keytruda: 2.2 months
Investigator-choice (carboplatin plus pemetrexed, cisplatin plus pemetrexed, carboplatin plus gemcitabine, cisplatin plus gemcitabine, or carboplatin plus paclitaxel): 2.2 months
Head and neck squamous cell cancer
Keytruda: 2 months (2-17)
Classical Hodgkin lymphoma
Keytruda: 2.8 months (1.0-31.2)
Adcetris (brentuximab vedotin): 2.8 months (1.0-7.3)
Classical Hodgkin lymphoma
Keytruda: 2.8 months (2.1-16.5)
Primary mediastinal large B-cell lymphoma
Keytruda: 2.9 months (2.4-8.5)
Urothelial Carcinoma
Keytruda: 2.1 months (1.3-9.0)
Urothelial Carcinoma
Keytruda: 2.1 months (1.4-6.3)
Investigator-choice (paclitaxel, Taxotere (docetaxel), Javlor (vinflunine)): 2.1 months (1.7-4.9)
Microsatellite instability-high or mismatch repair deficient cancer
Keytruda: Following ≥2 prior lines of standard chemotherapy - 4.3 months (1.8-24.9)
Following ≥1 prior lines of standard chemotherapy - 3.9 months (1.8-12.5)
Microsatellite instability-high or mismatch repair deficient cancer
Keytruda: 2 months (2-17)
Microsatellite instability-high or mismatch repair deficient cancer
Keytruda: 2 months (1.7-3.7)
Microsatellite instability-high or mismatch repair deficient cancer
Keytruda: 2.1 months
Microsatellite instability-high or mismatch repair deficient colorectal cancer
Keytruda: 2.2 months (1.8-18.8)
5-fluorouracil–based therapy with or without Avastin (bevacizumab) or Erbitux (cetuximab): 2.1 (1.7-24.9)
Gastric cancer
Keytruda: 2.1 months (1.7-6.6)
Esophageal cancer
Keytruda: 4.1 months (2.0-6.3)
Hepatocellular carcinoma
Keytruda: 2.1 months (1.8-4.8)
Merkel cell carcinoma
Keytruda: 2.8 months (1.5-9.7)
Renal cell carcinoma
Keytruda + Inlyta (axitinib): 2.8 months (1.5-16.6)
Sutent (sunitinib): 2.9 months (2.1-15.1)
Endometrial carcinoma
Keytruda + Lenvima (lenvatinib): 2.1 months
Investigator choice (doxorubicin or paclitaxel): 2.1 months
Cutaneous squamous cell carcinoma
Keytruda: 2.0 months (1.4-3.3)

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