The Lynx Group

PV-10 Therapy Shows Promise for Hepatic Tumors

June 2017, Vol 8, No 3

Hollywood, FL—A basket study of the oncolytic immunotherapy PV-10 (10% Rose Bengal disodium for injection), which included patients with tumors originating in various locations, showed that data for gastrointestinal lesions were especially encouraging, reported Paul M. Goldfarb, MD, FACS, a surgeon at Oncology Associates of San Diego, CA, at the 2017 Clinical Interventional Oncology annual symposium.

Dr Goldfarb described “intriguing” long-term survival in some patients with metastatic colorectal cancer (CRC) with a poor prognosis, and in an interview, called chemoablation with PV-10 “a therapy that potentially has real viability.”

Intralesional injections of PV-10 cause rapid disruption of tumor cells and immunogenic cell death, leading to T-cell priming and activation and eventual remote tumor regression. The majority of clinical testing of PV-10 has been in cutaneous melanoma that demonstrated high rates of complete response and durable local control; a phase 3 clinical trial of PV-10 versus chemotherapy or oncolytic virus therapy in melanoma is underway.

Dr Goldfarb presented data from 16 patients with hepatic lesions—5 patients with metastatic CRC with liver metastases, 6 patients with hepatocellular carcinoma (HCC), 2 patients with lung cancer, and 3 patients with melanoma, pancreatic cancer, or ovarian cancer. Patients with at least 1 liver tumor ≥1 cm received a single intralesional injection of PV-10 to a designated target lesion. After assessment at 28 days, patients could receive sequential injections to additional tumors.

At the last follow-up, 4 of 5 patients with metastatic CRC with hepatic tumors remained alive 9 months to 73 months after treatment, including 1 patient with no evidence of disease by 73 months. The fifth patient died from disease progression at 3 months.

“They were smaller lesions, and we were able to treat them completely. We had multi-year good disease control at a rate certainly as good as surgical resection,” said Dr Goldfarb.

“It’s simpler than doing radiofrequency or microwave or external radiation, and because the needle is dramatically smaller, there appears to be less risk of seeding. Also, it doesn’t preclude your coming back later and doing a surgical resection or other procedure,” he added.

In addition, 2 patients with HCC remained alive 75 months and 58 months (the former with no evidence of disease), respectively, after PV-10 treatment, and 1 patient with pancreatic cancer remained alive 12 months after PV-10 treatment. Overall, 2 patients with lung cancer and extensive multifocal disease died 4 and 12 months, respectively, after PV-10 therapy.

Overall, toxicity was transient. One elderly patient with an 8.9-cm HCC lesion died from an apparent thrombus that was not attributed to treatment. Expansion cohorts are assessing activity in multiple hepatic tumor types.

Advantages of PV-10 Therapy

Unlike radioembolization, which delivers yttrium-90 beads through the vasculature to an entire region of the liver, PV-10 does not appear to affect the liver beyond the injected tumor. “You’ve really limited exposure to the ablative mechanism to just the intended specific area of the tumor without affecting normal liver tissue,” he said.

Treatment for HCC has changed in recent years, with transplant becoming the primary mode of therapy, and therapies that serve as a bridge to transplant gaining interest, noted Dr Goldfarb.

“PV-10 may lend itself well to that, because it is minimally invasive, it doesn’t appear to injure surrounding liver tissues, and we haven’t observed significant scarring,” he said.

However, although PV-10 ablates HCC lesions, it does not necessarily address the underlying disease, Dr Goldfarb said, because potential immunogenic effects may not occur universally.

In addition, PV-10’s mechanism of action is appropriate for cancers that appear as isolated solid lesions, such as in hepatic and kidney cancer and melanoma, and may increase long-term remission in these cancers.

“My impression is that this therapy is agnostic to histology and works regardless of the histology of the primary tumor. Its utility may be limited for breast cancer or other cancers, which tend to be multifocal,” noted Dr Goldfarb.

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