Keytruda, known generically as pembrolizumab, is an immunotherapy agent produced by the American pharmaceutical company Merck & Co (MSD) for the treatment of various types of cancer. This drug is classified as a “checkpoint inhibitor,” which functions by disabling the mechanisms that inhibit the body’s T cells—essential components of the immune system—from attacking cancerous cells. Essentially, it harnesses the body’s immune capabilities to combat cancer.

The mechanism of pembrolizumab involves its binding to PD-1 receptors on T cells. This binding blocks T cells from interacting with PD-L1 receptors found on cancer cells, enabling T cells to recognize and mount an immune response against these abnormal cells.

Initially authorized by the United States Food and Drug Administration (FDA) in 2014 for the treatment of advanced skin cancer, Keytruda has since gained approval for several other cancers, including specific lung cancers, cervical cancer, renal cell carcinoma, and aggressive breast cancer. It is currently the highest-grossing drug worldwide, with revenue reaching $29.5 billion in 2024, accounting for nearly half of Merck & Co’s total earnings.

Keytruda is a key component of immunotherapy, a broad category of treatments that empower the immune system to fight diseases, primarily various cancers. Immunotherapy works alongside other treatment modalities such as chemotherapy, radiotherapy, and, when necessary, surgical interventions.

How does immunotherapy differ from traditional chemotherapy and radiation therapies?

Unlike chemotherapy and radiation, which directly aim to destroy cancer cells while also affecting some healthy cells, immunotherapy enhances the body’s natural immune response to recognize and eliminate cancer cells. This targeted approach tends to spare healthy cells and has shown promising outcomes in late-stage cancer patients, with some experiencing complete tumor regression. Immunotherapy has been associated with improved survival rates, even among those with aggressive cancer types.

What is Keytruda’s role within immunotherapy treatments?

Keytruda is categorized as a monoclonal antibody—synthetic molecules engineered to bind with specific targets, thereby enabling the immune system to identify and destroy malignant cells.

Other significant immunotherapy options include:

• CAR-T cell therapy: This process entails extracting a patient’s T cells, modifying them to create chimeric receptors, multiplying these engineered cells, and reintroducing them into the patient. These personalized T cells are then equipped to recognize and eliminate cancer cells that might otherwise evade immune detection.
• mRNA cancer vaccines: Currently under research, these vaccines differ from traditional vaccines as they are administered to patients with existing cancers to prevent recurrence. They work by training the immune system to detect neoantigens, which are proteins unique to cancer cells. Once identified, the immune system can remember these markers over the long term, continuing the fight against cancer.

Are immunotherapies accessible in India?

A variety of monoclonal antibodies, including Keytruda, are available in advanced healthcare facilities throughout India. Some generic alternatives, such as trastuzumab and nivolumab (another PD-1 inhibitor), can also be found.

While CAR-T therapy is highly effective, it is also costly and reliant on sophisticated technology. An Indian startup, ImmunoAct, incubated at IIT Bombay, has developed the country’s first indigenous CAR-T therapy named NexCar19, which is now among the most accessible options available.

What is the cost of Keytruda in India? What is the standard dosage? How can it be obtained? Are there insurance policies that cover it? Do specialized cancer care insurance plans include it?

Merck & Co recommends a dosage of 200 mg every three weeks. Each 100 mg vial is priced at over Rs 1.5 lakh, meaning that patients without insurance or financial aid may face monthly costs exceeding Rs 3 lakh.

Consequently, many patients in India access Keytruda through the company’s Patient Access Program, which offers 30 complimentary vials after an initial purchase of five for approximately Rs 10 lakh. Patients can utilize third-party health insurance for the initial dose, but the program has specific criteria—such as a maximum annual income of Rs 25 lakh.

While standard health insurance may cover some costs associated with these therapies, specialized cancer care policies are tailored to help with the expenses of such high-cost medications. Additionally, certain government health programs, like CGHS, may also provide access to these treatments.

Why is Keytruda priced so high? Is a more affordable alternative on the horizon?

The manufacturing complexity of monoclonal antibodies like Keytruda makes them more expensive than simpler medications, such as Paracetamol. A significant portion of the cost is attributed to patent protections. Keytruda’s patent is set to expire in 2028, with various companies already in the process of developing generic alternatives that could reduce prices by as much as 70%.

What significance does India hold for Merck in the Keytruda market?

With one of the largest populations globally and an increasing incidence of cancer, access to immunotherapy in India is largely hindered by financial barriers. Although the cancer incidence rate in India is currently lower than the global average, it is steadily rising. Recent estimates from the Global Burden of Disease indicate that cancer rates have increased from 84.8 cases per 100,000 people in 1990 to 107.2 per 100,000 in 2023.

Data from the WHO’s Global Cancer Observatory reveals that India recorded 1.413 million cancer cases in 2022, with projections suggesting a surge of 73.8% to 2.456 million cases by 2045. GLOBOCAN estimates place India’s incidence rate at 98.5 per 100,000. In contrast, Australia, which has one of the highest rates at 462.5 per 100,000, is expected to see a more modest increase of 49.9% by 2045, with case numbers rising from 212,000 in 2022 to 318,000 by 2045.

In light of these trends, the Indian government has taken measures to reduce the financial burden of Keytruda by eliminating the basic customs duty on the drug last year.