Novel Clinical Trial Helping Late-Stage Mesothelioma Patients

Research & Clinical Trials

Late-stage patients with pleural mesothelioma have survived longer than anticipated — with good quality of life — in a phase I clinical trial studying the effectiveness of a novel combination treatment.

The treatment involves galinpepimut-S, the latest targeted cancer vaccine also known as GPS, in combination with Opdivo, a popular immunotherapy drug.

Memorial Sloan Kettering Cancer Center is hosting the study sponsored by SELLAS Life Sciences Group, a late-stage clinical biopharmaceutical company based in New York City.

“We’ve seen some very, very positive results,” Dr. Dragan Cicic, director of Clinical Development at SELLAS, told The Mesothelioma Center at “Patients in advanced stages can still go forward with a solid quality of life. This is very promising.”

Patients Find Hope in Trial

All patients started the trial after previous treatments had stopped working, or never slowed their tumor progression, leaving them with little hope in the final stages of a cancer with no cure.

“What we’re seeing in our study is increased survival in comparison to other trials out there,” Cicic said. “Our goal is to bring this treatment to as many patients as possible. The ultimate goal is to expand it, and make it something that can benefit all patients, and not just those with access to the clinical trial.”

Early results of this single-center trial included a median overall survival of 10.5 months from the time the earlier treatment was stopped.

By comparison, patients with relapsed or refractory mesothelioma typically have an estimated overall survival of just 20-24 weeks.

Six of the eight patients in this latest trial arrived in stage 3 or 4. The median survival time of 10.5 months is expected to improve as the trial progresses. Half of the patients were alive when results were released.

The median progression-free survival, from the start of the combination, was 11.9 weeks.

Vaccine Fills Huge Void for Patients

There is currently no FDA approved second-line therapy for pleural mesothelioma, but Cicic believes this latest combination could eventually fill that void.

Opdivo, also known generically as nivolumab, was approved by the FDA in 2020 for first-line treatment of mesothelioma in combination with Yervoy, another immunotherapy drug.

In combination with Keytruda, GPS also showed surprising effectiveness recently in a clinical trial with late-stage cases of ovarian cancer.

GPS works by targeting the WT1 protein, which is expressed in unusually high levels in several cancers but rarely seen in normal adult cells. Standard of care chemotherapy has been ineffective in targeting the WT1 protein.

According to Cicic, the combination has shown little or no side effects beyond what is expected with Opdivo, which is minimal.

“This is a very good option for patients, very little in terms of side effects,” Cicic said. “It shows that mesothelioma stage 4 does not have to be an immediate death sentence.”

Vaccine Working Toward FDA Approval

In 2016, the FDA granted Fast Track status to GPS. Fast Track was designed to expedite the drug review process, which normally takes 10 years, and provide financial incentives for the developers. It also is aimed at unmet medical needs for tough-to-treat cancers like mesothelioma.

As a single agent, GPS also has shown effectiveness in several early-stage cancers. When used in combination with surgery, the vaccine improved median survival 25% in one clinical trial with mesothelioma patients. In another trial combination that involved complete resection, the vaccine almost doubled the median survival time when compared to a control arm.

“This updated data is very encouraging,” said Dr. Angelos Stergiou, president and CEO of SELLAS. “Of additional importance is the fact that both recent trials (for mesothelioma and ovarian cancer) addressed patients with bulky, active disease, the setting in which other cancer vaccines have had very little effect.”

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