This clinical trial is continuing the research of a mesothelioma drug adapted from the virus used to make the smallpox vaccine. It has already shown positive results in some patients.

Mesothelioma Virotherapy

Virotherapy is a branch of treatment that uses a genetically modified virus to attack a disease. The drug in this study, GL-ONC1, has been engineered to target pleural mesothelioma cells. This experimental drug has proven to be well-tolerated among clinical trial candidates and has also begun to show promise fighting mesothelioma cells.

  • GL-ONC1
    GL-ONC1 Defined – This drug is a genetically modified form of the vaccinia virus, which was used to develop the smallpox vaccine. GL-ONC1 invades mesothelioma cells and infects tumors with the modified virus while leaving healthy cells unharmed.

Doctors have known for decades that viruses could be used to kill cancerous cells. However, the technology wasn’t developed enough until very recently to safely deliver viruses to fight cancer. Now, drugs like GL-ONC1 contain genetically modified viruses that are designed to leave healthy cells unharmed, which reduces potential side effects.

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The ultimate goal of GL-ONC1 is to eradicate mesothelioma tumors. While it’s only in the early phases of clinical trials, there is considerable optimism surrounding this drug.

Mesothelioma patients may benefit from this trial because it:
  • Offers new treatment options to late stage patients and those who aren’t responding well to standard treatments
  • Provides treatment from leading mesothelioma specialists at one of the country’s most renowned cancer centers
  • Has already shown potential for being effective against mesothelioma

GL-ONC1 Behind the Scenes

GL-ONC1 is part of an emerging form of cancer treatment known as oncolytic virotherapy. This is just a scientific way of saying, “fighting cancer with viruses.”

The virus that makes up GL-ONC1 is a modified vaccinia virus. The viral particles in the drug target and invade mesothelioma cells inside the tumor, growing and replicating. This leads to the destruction of mesothelioma cells and releases developed viral particles back into the tumor to infect other individual mesothelioma cells. This creates a domino effect of tumor cell destruction.

The virus also activates genetic markers that emit light visible on CT scans and can be used by doctors to track the progress of the virus. This also allows doctors to monitor the progression of the disease itself more easily.

The biggest advance in virotherapy like this was the ability of scientists to genetically engineer viruses. This was necessary so the virus could withstand assaults from the immune system and target cancerous cells.

Role of the Immune System

GL-ONC1 also engages the immune system, which adds an extra line of offense to attack the disease. This happens when tumor cells are killed and release antigens that are recognized by the immune system. The antigens act as a signaling mechanism for immune cells to attack mesothelioma cells. This continues until tumors are destroyed.

Additionally, GL-ONC1 relies on the mesothelioma tumor and its cells for protection from natural immune responses. Therefore, once tumors are destroyed, the virus is also destroyed which can be determined by the lack of light emission.

Who Is This Trial For?

This trial may benefit any patient with mesothelioma. Those who are not eligible for surgery most likely to benefit. Qualifying for eligibility is also fairly straightforward and not as strict as for some other trials.

General eligibility criteria includes:

  • No sign of brain metastasis
  • Two weeks since treatment with chemotherapy, radiation and/or immunotherapy (palliative radiation is an exception)
  • Have not had any prior gene therapy or virotherapy


This clinical trial is being conducted exclusively at Sloan-Kettering. This cancer center is one of the most renowned treatment and research facilities for mesothelioma. Not only do participants in this study reap the benefits of receiving care from the top doctors in the field, they also get the comfort of knowing Sloan-Kettering is a front-runner in developing effective experimental treatments.

  • Memorial Sloan-Kettering Cancer Center

    Memorial Sloan-Kettering Cancer Center

    Principal Investigator: Dr. Valerie Rusch
    Dr. Rusch is one of the leading mesothelioma surgeons in the country. She has led many mesothelioma clinical trials at Memorial Sloan-Kettering. Her work has contributed to longer lives for many of her patients. Although this trial is still in the early phases, Dr. Rusch said that, “clearly we have a number of patients who have stable disease.”

Is This Trial for You?

Clinical trials for mesothelioma are a gateway to innovative, experimental treatments when other avenues of treatment have closed. This trial may be beneficial for patients at any stage, but late stage patients have the most to gain. If you want to participate in this study, we can get you connected to Sloan-Kettering and discuss other clinical trial options as well. Get connected to this clinical trial today.