Study: Immunotherapy Vaccine for Mesothelioma Still Promising

The ONCOS-102 immunotherapy vaccine continues its move toward future, first-line standard of care treatment for malignant pleural mesothelioma, based upon the latest study follow-up data.

When combined with standard chemotherapy, the genetically modified adenovirus has produced a median overall survival of at least 18.2 months, according to results released in late November from the ongoing clinical trial.

Median overall survival was more than four months better than the control group receiving chemotherapy alone in the randomized trial.

ONCOS-102 is manufactured by Targovax, a small Scandinavian biotech company focused on oncolytic viruses targeting hard-to-treat solid tumors.

“At this point, we’re pretty confident that it will become part of standard of care for mesothelioma in the future,” Dr. Magnus Jaderberg, chief medical officer at Targovax, told The Mesothelioma Center at Asbestos.com. “This is exactly what we had hoped to see.”

Vaccine Shows Strong Immune System Activation

The multicenter study across France and Spain involves 31 patients, 20 of whom received the vaccine/chemotherapy combination, and many of whom had inoperable, advanced-stage disease.

At the 18-month follow-up, more than half the participants were still living, sparking a belief that the difference between the two groups will further increase at the next follow-up in 2021.

Earlier reports listed the 12-month survival rate at 64% and few side effects beyond what is expected normally with chemotherapy.

Study analysis throughout has shown a robust immune system activation.

“Our numbers are small, but the data is pointing in the right direction,” Jaderberg said. “We are starting to see the immune activation translating into encouraging, improved survival outcomes.”

Another FDA Approval Possible

In October, the U.S. Food and Drug Administration granted historic approval to the immunotherapy combination of Opdivo and Yervoy for first-line treatment of mesothelioma after showing similar four-month improvement advantages.

It was the first new drug regimen approved for mesothelioma in 16 years.

Targovax already has announced plans for another clinical trial, spread across several United States cancer centers and a few in Europe. It will combine ONCOS-102 with Keytruda, known generically as pembrolizumab and manufactured by pharmaceutical giant Merck & Co.

That study will start early in 2021 and include Memorial Sloan Kettering Cancer Center in New York City.

“We could end up with a very powerful immunotherapy combination,” Jaderberg said during an earlier interview with The Mesothelioma Center.

Combinations Are Key to Vaccine Effectiveness

Based upon the latest results, Jaderberg believes strongly that ONCOS-102 will be best used in a combination treatment that ignites a synergistic, immunotherapy effect between multiple drugs.

The FDA already approved Keytruda for mesothelioma in a second-line setting, but only for a small percentage of patients expressing high levels of PD-L1, a particular cell-surface protein.

Many oncologists believe that adding ONCOS-102 could make Keytruda much more effective and expand the percentage of mesothelioma patients for whom it would work well.

Until now, a multidisciplinary combination of chemotherapy, surgery and radiation has been the most effective therapy for pleural mesothelioma.

Unfortunately, less than a third of those diagnosed have been eligible for aggressive, potentially curative surgery because the disease is too far advanced.

Urgent Need for Improved Mesothelioma Treatments

Standard of care, until the approval last month, involved the intravenous use of the pemetrexed and cisplatin chemotherapy combination. The median overall survival has stayed in the 12-month range for many years.

ONCOS-102 has been engineered to selectively infect cancer cells and activate the immune system. It also is being studied with colorectal cancer and melanoma. Impressive results from a melanoma clinical trial are expected to be announced in December.

“There is a huge medical need for these mesothelioma patients right now – a massive need for a new treatment that can provide better long-term outcomes,” Jaderberg said. “We’re excited about what we’ve seen.”

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