Modified herpesvirus completely wiped out terminal cancer

A patient in a study testing a herpesvirus-based cancer treatment saw his cancer disappear completely and has remained cancer-free in the 15 months since his treatment began, the Institute of Cancer Research (ICR) in London said.

The result for west London builder Krzysztof Wojkowski was the most dramatic result seen in the small Phase 1 trial of an experimental cancer therapy called RP2. Thirty-nine patients who had exhausted all other treatment options received the treatment. Nine received viral therapy alone, while 30 received it in combination with immunotherapy.

“I was told there were no more options for me and that I would receive end-of-life care,” Wojkowski said in the statement. “It was devastating, so to get the chance to be part of the process was incredible.”

While it’s still early days, the findings, presented at the 2022 European Society for Medical Oncology congress in Paris, offer further evidence that cancer-killing viruses may be up to the task of wiping out cancer where other methods have failed, and “Can provide potent systemic antitumor effects,” the authors write in their poster.

A patient in a study testing herpes’ ability to fight cancer saw the virus wipe him out completely.

The virus: RP2 isn’t just any herpesvirus: it’s a genetically modified version of the herpes simplex virus (HSV-1), the culprit behind cold sores (and an incredibly common pathogen, affecting over 50% of US adults).

Herpesviruses, which include the viruses behind chickenpox and genital herpes, have developed a number of remarkable abilities, including the trick of infecting and hiding within nerve cells from which they regularly erupt to flare up sores or rashes like shingles.

They also preferentially infect cancer cells. The HSV-1 in the UK study was further modified to specifically target tumor cells and made “oncolytic” – meaning it infects and kills cancer cells.

Injected directly into tumors, the virus hijacks the tumor cells, replicates, and explodes them from within — while blocking the production of a protein called CTLA-4, which the tumor uses to restrain your immune system.

When the virus is running, the immune system can do what it does best: kill rogue cells.

This isn’t the first time we’ve developed a modified herpesvirus to fight cancer—modified versions of HSV-1 have previously shown success in melanoma and brain tumors.

In fact, IRC researchers have previously developed T-Vec, a virus approved by the NHS to treat skin cancer. Lead researcher Kevin Harrington told the BBC that RP2 is like T-Vec with even more teeth.

“It has other modifications of the virus so that when it gets into cancer cells, it effectively signs their death warrant,” Harrintgon said.

“I was told there were no more options for me and that I would receive end-of-life care. It was devastating so to get the chance to be part of the process was incredible.”

KRZYSTOF WOJKOWSKI

The process: The ongoing Phase 1 study, conducted with The Royal Marsden NHS Foundation Trust and sponsored by RP2 manufacturer Replimune, was designed to test the drug’s safety and best dosage, as well as its ability to shrink different types of tumours.

Thirty-nine patients were enrolled whose cancer had not responded to other treatments.

Of the nine patients who received only RP2, three saw results. In two of them, one with cancer of the esophagus and the other with a rare eye cancer called uveal melanoma that had spread to the liver, the tumors shrank but the cancer’s progression was still halted 15 and 18 months after treatment, respectively.

The other patient, West London builder Wojkowski, had his salivary gland cancer completely eradicated.

Of the 30 patients who received RP2 along with an immunotherapy called nivolumab, seven responded to the combined drugs. In melanoma, choroidal melanoma, and head and neck cancer patients, their cancer growth stopped or shrank. At 14 months, six of the seven cancers had still not progressed.

When the patient’s tumors were biopsied before and after the injection, they found evidence that herpes was working to activate the immune system, with more immune cells around the tumor. The drug caused mild side effects, including fever, chills, and fatigue.

Although it’s a small and ongoing study, these early results are promising, Jonathan Zager of Tampa’s Moffitt Cancer Center told Insider.

“We will see more studies in the near future and I’m excited – certainly not discouraged or skeptical,” said Zager.

“Viruses are one of humanity’s oldest enemies, as we have all seen during the pandemic. But our new research suggests we can exploit some of the properties that make them challenge opponents to infect and kill cancer cells.”

KRISTIAN HELIN

Next Steps: “Our study shows that a genetically engineered, cancer-killing virus can deliver a double whammy against tumors – by destroying cancer cells directly from the inside while simultaneously using the immune system against them,” Harrington said in a statement.

The next step is to test RP2 in more patients to see if its effectiveness lasts, particularly in cancers that are resistant to current treatments.

“Viruses are one of humanity’s oldest enemies, as we’ve all seen during the pandemic,” said Kristian Helin, IRC’s executive director.

“But our new research suggests we can exploit some of the properties that make them challenge opponents to infect and kill cancer cells.”

This article was originally published by our sister site Freethink.