What is the MOA of Loqtorzi (toripalimab)?

Key Points

• Loqtorzi (toripalimab) is a programmed death receptor-1 (PD-1) blocking antibody that binds to the PD-1 protein on T-cells (a type of immune cell).
• It works by blocking PD-L1 and PD-L2 molecules found on the surface of some cancer cells. This allows the immune system to activate and kill the tumor.
• Loqtorzi was the first FDA-approved agent for treatment of nasopharyngeal carcinoma (NPC), a rare type of head and neck cancer.

Loqtorzi was approved on October 27, 2023 for the treatment of advanced nasopharyngeal carcinoma (NPC). It is used:

• as first-line treatment of adult patients with metastatic (cancer that has spread) or with recurrent (cancer that has returned) in nearby tissues (locally advanced NPC) in combination with cisplatin and gemcitabine.
• as a single agent for the treatment of adult patients with recurrent unresectable (cannot be removed surgically) or metastatic NPC with disease progression on or after a platinum-containing chemotherapy (the chemotherapy did not work or is no longer working).

What is nasopharyngeal carcinoma?

Nasopharyngeal carcinoma is an aggressive type of cancer that starts in the upper part of the throat behind the nose and near the base of the skull (called the nasopharynx). Surgery is rarely an option due to the location of the cancer, so patients with localized cancer may be treated with radiation and chemotherapy.

How does Loqtorzi work in cancer?

Loqtorzi is known as an immune checkpoint inhibitor. Loqtorzi works with the immune system to help fight cancer and is considered an immunotherapy treatment. It is given as an intravenous (IV) infusion.

The immune system helps to guard the body from infections due to bacteria, viruses, and even cancer. The immune system has a memory, too, and it can remember and recognize when foreign invaders, such as cancer, attempt to inhabit our body.

However, the immune system is not perfect in fighting these intruders. It appears some tumors can 'turn off' the ability of cancer-fighting cells such as T-cells (a type of white blood cell) to attack these foreign cells.

• Our immune system needs to be able to tell the difference between foreign invaders and healthy tissue so that our cells and organs are not mistakenly attacked. To do this, our immune system has a set of "brakes", like a bike, that can help it to stop and go.
• When the immune system brakes are "off", it's active and attacks cells that are considered foreign invaders such as cancer. Our immune system is very good at this, but cancer can still fool the "brakes".
• When the T-cell is stopped (the "brakes" are on) it can't fight the cancer. Loqtorzi works by helping to reactivate these T cells by releasing the “brakes”.

Loqtorzi is classified as an anti-PD-1 monoclonal antibody. T-cells (a type of white blood cell found in our body) help protect us from infection and may help fight cancer. When PD-L1 (a protein found on some cancer cells) binds to another protein called PD-1 (found on T cells), it has a negative effect - it keeps T cells from killing the cells that contain PD-L1, including the cancer cells.

Normally, this mechanism (immune checkpoint) is used to help prevent our body from attacking normal cells, but when it happens with cancer cells, the cancer can grow unchecked.

That’s where immune checkpoint inhibitors come into play. Immune checkpoint inhibitors like Loqtorzi bind to PD-L1 and block (prevent) its binding to PD-1. This releases the “brakes” on the immune system and leaves T cells and their immune response free to kill cancer cells.

Examples of checkpoint proteins found on T cells or cancer cells include PD-1/PD-L1 and CTLA-4/B7-1/B7-2.

Examples of other common immune checkpoint inhibitors used to treat cancer include pembrolizumab (Keytruda), ipilimumab (Yervoy), and nivolumab (Opdivo).

Which immune checkpoint inhibitors are approved by the FDA?

The number of approved Immune Checkpoint Inhibitors has skyrocketed in recent years. These medicines now play a major role in cancer treatment for some of the most advanced cancers. These include:

• Yervoy (ipilimumab)
• Opdivo (nivolumab)
• Keytruda (pembrolizumab)
• Tecentriq (atezolizumab)
• Bavencio (avelumab)
• Imfinzi (durvalumab)
• Libtayo (cemiplimab-rwlc)
• Jemperli (dostarlimab-gxly)
• Opdualag (nivolumab and relatlimab)
• Imjudo (tremelimumab-actl)
• Zynyz (retifanlimab-dlwr)
• Tevimbra (tislelizumab-jsgr)

This is not all the information you need to know about toripalimab (Loqtorzi) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

See also:

Related medical questions

• What are Monoclonal Antibodies and how do they work?
• How does Loqtorzi work for nasopharyngeal carcinoma?
• How Accurate is Screening for Nasopharyngeal Carcinoma?

Drug information

• Toripalimab Information for Consumers
• Toripalimab prescribing info & package insert (for Health Professionals)
• Side Effects of Toripalimab (detailed)

Related support groups

• Toripalimab (4 questions, 4 members)
• Nasopharyngeal Carcinoma (3 questions, 4 members)

Medical Disclaimer