Health New Zealand has explained a U-turn to give a small group of cancer patients early access to Keytruda treatment.

It had earlier said it would wait to offer patients the drug, until Pharmac funding started in October.

Chief Clinical Officer Richard Sullivan says up to 30 people can get the drug this month.

"After reaching out to our clinical colleagues in our cancer centres, recognising the number of patients we could bring in early under this access program - is a small number we felt the system could do."

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