An analysis of data from a Phase II study of Merck & Co's immunotherapy Keytruda has demonstrated high response rates in heavily pre-treated patients with relapsed or refractory classical Hodgkin lymphoma (cHL).

The analysis of outcome measurements from three different patient cohorts in the KEYNOTE-087 trial showed the the overall response rate (ORR) to be more than 70 percent, while 90 to 93 percent of patients experienced a reduction in tumour size.

In Cohort 1 (progressed after transplant and subsequent brentuximab vedotin treatment; n=30), ORR to Keytruda (pembrolizumab) was 73 percent, with complete responses in 27 percent and partial responses in 47 percent.

In Cohort 2 (progressed following salvage chemotherapy, transplant-ineligible, and progressed following brentuximab vedotin treatment; n=30), ORR was 83 percent, with complete responses in 30 percent and partial responses in 53 percent.

In Cohort 3 (progressed after transplant and not treated with brentuximab vedotin after transplant; n=30), ORR was 73 percent, with complete responses in 30 percent and partial responses in 43 percent of patients.

"Recurrence of Hodgkin lymphoma occurs in almost half of patients following autologous stem cell transplantation, and the prognosis for patients relapsing or refractory to second-line chemotherapy and transplant is particularly poor, which means there is a significant need to identify therapeutic options that provide meaningful clinical benefit," noted Dr Craig Moskowitz, clinical director, division of haematologic oncology, Memorial Sloan Kettering Cancer Center.

Data 'encouraging'
"These early data are encouraging, as they demonstrate high response rates - up to 83 percent - with pembrolizumab in heavily pre-treated patients."

The safety profile of Keytruda in the trial was consistent with that reported in previous studies, with Grade 3-4 treatment-related adverse events - including neutropenia, increased amylase, cytokine release syndrome, herpes zoster, increased lipase, lichenoid dermatosis, colitis, and diarrhoea - observed in 4 percent of patients. Two discontinued due to treatment-related side effects.

The drug - a humanised monoclonal antibody that boosts the body's immune system to help detect and fight tumour cells, by blocking the interaction between PD-1 and its ligands to activate T lymphocytes - is approved for unresectable or metastatic melanoma and for certain non-small cell lung cancer populations.