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ASCO 2016: Nivolumab Shows Promise in Refractory, Metastatic Anal Cancer

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Key Points

  • Of the 37 patients evaluable for response based on intent to treat, two patients (5%) had a complete response, seven (19%) had a partial response, and 17 (46%) had stable disease—a control rate of 70%.
  • The median progression-free survival was 3.9 months.
  • This is the first completed anti–PD-1 study to include HIV-positive patients as well as patients with Hepatitis B or C. Two HIV-positive patients were enrolled in the trial.

In the first-ever clinical trial for metastatic patients previously treated for the disease, research led by The University of Texas MD Anderson Cancer Center found that the immune checkpoint inhibitor nivolumab (Opdivo) shows promise for the majority of patients with squamous cell carcinoma of the anal canal (SCCA). The study also is the first to investigate the use of immunotherapy in this patient population.

The prospective phase II trial findings were presented at the 2016 ASCO Annual Meeting by Cathy Eng, MD, Professor of Gastrointestinal Medical Oncology at MD Anderson and the study’s national principal investigator (Abstract 3503).

According to the American Cancer Society, more than 8,000 people will be diagnosed with anal cancer in the United States in 2016 and more than 1,000 people will die from the disease. About 20% of patients present with metastatic SCCA, and an additional 20% who had early-stage disease will later develop metastatic anal cancer, explained Dr. Eng.

“Although a rare malignancy, the incidence is on the rise and has a strong association with the human papillomavirus (HPV),” said Dr. Eng, who is also co-leader of MD Anderson’s HPV-related Cancer Moon Shot. “There are no standardized treatment options for metastatic anal cancer patients, so there’s truly an unmet need in those whose disease has not responded to initial therapy.”

Study Details

Conducted through the National Cancer Institute’s (NCI) Experimental Therapeutic Clinical Trial Network and Cancer Therapy Evaluation Program, 39 patients enrolled in the trial, NCI9673, with 37 patients receiving treatment. MD Anderson enrolled 18 patients. All were previously treated; however, prior immunotherapy treatment was not allowed. Programmed death ligand-1 (PD-L1) expression was not required for participation. The study’s primary endpoint was response rate, with overall and progression-free survival rates (OS and PFS, respectively) and toxicity as secondary endpoints.

The study closed within 5 months of opening because of the rapid accrual rate—underscoring the unmet need in this patient population.

Also of note, this is the first completed anti–PD-1 study to include HIV-positive patients as well as patients with Hepatitis B or C. Two HIV-positive patients were enrolled in the trial.

“Immunosuppression is a known risk factor for this disease. Since HIV predisposes patients to compromised immune systems, it is a well-defined risk factor for anal cancer,” said Van Morris, MD, Assistant Professor of Gastrointestinal Medical Oncology at MD Anderson. “It was important to include a patient population that was representative of this disease.”

Findings

All patients received nivolumab every 2 weeks. Of the 37 patients evaluable for response based on intent to treat, two patients (5%) had a complete response, seven (19%) had a partial response, and 17 (46%) had stable disease—a control rate of 70%. The median PFS was 3.9 months. Six patients remain on study. Common adverse events included fatigue, anemia, and rash; there was one incident of pneumonitis.

“Our findings represent an exciting step forward for patients with no standard of care. We now plan to expand the study further looking at combined immunotherapy agents,” said Dr. Eng.

The study was supported by MD Anderson’s HPV Moon Shots Program and the HPV and Anal Cancer Foundation, the E.B. Anal Cancer Fund, an NIH N01 award and a philanthropic donation.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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