Young patients whose lives are blighted by an aggressive blood cancer have been offered new hope by an experimental immunotherapy drug.
Of those taking part in a new trial, 66.3% experienced "considerable" shrinking of their tumours and typically remained symptom-free for nearly eight months.
The drug, nivolumab, is one of a new generation of "smart" medicines that interfere with the ability of cancers to shield themselves from the immune system.
Known as a "checkpoint inhibitor", it has already proved affective against melanoma, the most dangerous form of skin cancer, and one type of lung cancer.
The new study looked at nivolumab's ability to tackle classical Hodgkin's lymphoma in patients who failed to respond to other treatments and "rebooting" of their immune systems using transplants of stem cells taken from their own bone marrow.
A total of 80 patients took part in the Phase II trial, ranging in age from 18 to 72.
Hodgkin's lymphoma develops in the lymph system and affects immune system blood cells called B-lymphocytes. In 2013, 1,954 people in the UK were diagnosed with the disease. Of these, 95% had the "classical" form of the illness.
Most of those affected are young adults in their early 20s and older people over 70.
Dr Graham Collins, consultant haematologist from Oxford University Hospitals Foundation Trust, a member of the trial team, said: "Every year in the UK, around 2,000 people are diagnosed with Hodgkin lymphoma and, sadly, many will be in their 20s or 30s.
"If a patient's cancer progresses despite available treatment, there is often little that can be done. For the first time in this very sick patient group we are seeing immunotherapy treatment considerably reduce cancer burden in a majority of patients.
"Nivolumab is now offering real promise in this disease. The hope is that this will translate into longer survival in more patients than has been possible to date."
Results from the CheckMate - 205 trial were presented at the annual meeting of the European Haematology Association in Copenhagen, Denmark, and are due to be published in the journal The Lancet Oncology.
Jonathan Pearce, chief executive of the Lymphoma Association, said: "It is vital that innovative treatments are being developed and made available to lymphoma patients.
"We want everyone affected by lymphoma to receive the best possible treatment and care, and the more options there are to improve outcomes and quality of life for patients, the better."