Evaluating PD-1 inhibitor therapy for recurrent or non-responsive classical Hodgkin lymphoma

This phase 2 study evaluated the effectiveness and safety of camrelizumab alone or in combination with decitabine (Dacogen) for recurrent or non-responsive classical Hodgkin’s lymphoma (cHL). This study concluded that the combined treatment was safe and highly effective in these patients.

Standard first-line chemotherapy is highly effective in treating 70 – 80% of patients with cHL. Unfortunately, many patients experience cancer recurrence or develop disease that stops responding to treatment. PD-1 inhibitors such as nivolumab (Opdivo), pembrolizumab (Keytruda) or camrelizumab may help.

PD-1 inhibitors bind to cancer cells, marking them as targets for the body’s immune system. This leads to cancer cell death. This treatment is effective in most patients. However, for those whose cancer comes back, treatment remains challenging. Adding decitabine to camrelizumab treatment is another option. Decitabine is a chemotherapy drug. The effectiveness and safety of this combination are under investigation.

This study had 86 patients with cHL that has come back or stopped responding to treatment. Patients were divided into two groups. Patients in the first group were not treated with anti-PD-1 inhibitors before. These patients were given either camrelizumab alone or combined with decitabine (group 1). Patients in the second group did have anti-PD-1 inhibitor therapy before. These patients were given camrelizumab plus decitabine (group 2). Patients were followed-up for an average of 14.9 months.

In group 1, significantly more patients given combination treatment had a complete disappearance of cancer compared to patients treated with camrelizumab alone (71% vs. 32%). At 6 months after treatment, more patients given combination treatment were still alive without tumor growth or spread compared to patients treated with camrelizumab alone (100% vs. 79%). At 1 year, this rate was 89% vs. 59%.

In group 2, 28% of patients had a complete disappearance of cancer. In group 2 the overall response to decitabine and camrelizumab combination was 52%. 24% of patients in this group had tumor shrinkage. 79% of patients were still alive 6 months later without tumor growth or spread. At 1 year, this rate was 59%.

Overall, 84 patients experienced side effects. More patients on combined treatment developed low white blood cell count (76% vs. 32%). 39% of patients on combined treatment developed severely low white blood cell count. More patients on combined treatment had immune-related side effects compared to treatment with camrelizumab alone (30% vs. 26%).

This study concluded that camrelizumab plus decitabine was more effective for patients who were not previously treated with anti-PD-1 inhibitors. The authors suggest that this combination may help patients with cHL that stopped responding to anti-PD-1 inhibitor therapy.

This was a small study with a short follow-up period. Larger studies are needed to confirm these results.