A mesothelioma patient has received a first dose of the CA-170 immunotherapy drug in a Phase 1 trial looking at patients with various advanced tumors and lymphomas, including a mesothelioma cohort (a group of mesothelioma patients).

Curis, Inc. — a biotechnology company that focuses on treatments for cancer — announced that the first mesothelioma patient was dosed in the Phase 1 trial of CA-170 ahead of schedule.

CA-170 is a drug that works to stop V-domain Ig Suppressor of T-cell Activation (VISTA) and programmed death-ligands 1 (PD-L1) from sending their messages throughout the cancer site because these messages encourage tumors to grow.

Stopping these substances from sending their growth signals could prevent the multiplication of mesothelioma cells.

About the Phase 1 CA-170 Study

Three hundred cancer patients whose tumors are no longer responding to standard treatments are participating in this study at several cancer center locations across the United States.

Like all Phase 1 clinical trials, this study focuses on finding a safe dose of the new CA-170 immunotherapy drug. To find the safe dose, patients will be given increasingly stronger doses to determine the safest amount that will produce some results without causing too many dangerous side effects.

The researchers are hopeful they will determine the maximum tolerated dose of CA-170, and how many patients hit the dose-limiting toxicity level — the amount of CA-170 they can receive before it becomes too much for their bodies.

If researchers can find this maximum tolerated dose in the first cycle of treatment, they can determine the recommended dose for Phase 2.

About the CA-170 Immunotherapy Drug

CA-170 is an oral medication. Preclinical studies showed it was safe to take once a day. However, drugs that are not tested on humans may not react the same way in the human body.

This is why phase 1 studies need to determine a safe dose, instead of using the one the researchers already found to work in Petri dishes or animals tests.

CA-170 is a type of immunotherapy drug, which means that it works with the body’s immune system to fight cancer. In this case, CA-170 targets both VISTA and PD-L1, which are both checkpoint inhibitors — meaning they both tell the immune system there is nothing wrong with the body and to stop fighting.

By targeting these substances, CA-170 helps activate the body’s immune system to better fight mesothelioma cells.

How CA-170 Can Help Mesothelioma Patients

VISTA is a checkpoint inhibitor found naturally in the body. However, when a person has mesothelioma, the amount of this inhibitor increases.

Over 90% of mesothelioma cells create VISTA. This is a problem because VISTA stops T-cells — the white blood cells that protect your body from diseases —from working.

VISTA-production has also been identified as one of the reasons PD-L1 inhibitor drugs don’t work as effectively as researchers would have thought. PD-L1s are proteins. Like VISTA, they also stop T-cells from working properly.

Previous studies have shown that PD-L1 inhibitor drugs stop PD-L1 proteins from sending their messages to T-cells, the body’s immune system activates and can attack cancerous cells.

PD-L1 and VISTA deactivate the immune system for different reasons.

Because they each have different mechanisms for preventing the immune system from responding, a therapy that targets both can potentially increase treatment effectiveness by addressing both issues in one drug.

Hope for Patients With Advanced Mesothelioma

If the Phase 1 trial goes well, CA-170 will move to Phase 2 trials where researchers will look at how well the medication works. Then, hopefully, it will move to Phase 3 trials where it will be available on a broader scale.

If CA-170 makes it through all of the clinical trials, it will mean that patients will have access to a new type of mesothelioma treatment.

This is especially important for patients with advanced mesothelioma who are no longer responding to chemotherapy and to those whose mesothelioma has relapsed after having been treated with chemotherapy.

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Laura WrightWritten by:

Lead Editor

Laura Wright is a journalist and content strategist with more than 15 years of professional experience. She attended college at the University of Florida, graduating magna cum laude with a bachelor’s degree in journalism in 2008. Her writing has been featured in The Gainesville Sun and other regional publications throughout Florida.

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  1. “First Mesothelioma Patient Dosed in CA-170 Study” BioSpace. Retrieved from: https://www.biospace.com/article/releases/first-mesothelioma-patient-dosed-in-ca-170-study/. Accessed January 30, 2019.

  2. “A Study of CA-170 (Oral PD-L1, PD-L2 and VISTA Checkpoint Antagonist) in Patients With Advanced Tumors and Lymphomas” ClinicalTrials.gov. Retrieved from: https://clinicaltrials.gov/ct2/show/NCT02812875. Accessed January 30, 2019.

  3. “CA-170 (Oral, Small Molecule VISTA/PD-L1 Antagonist)” Curis. Retrieved from: http://www.curis.com/pipeline/ca-170. Accessed January 30, 2019.

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