Pharmac has struck a provisional deal to fund a breast cancer drug which petitioners and sufferers have been demanding.

Government drug-buying agency Pharmac has proposed to fund Palbociclib, marketed as Ibrance, after reaching an agreement with supplier Pfizer.

Health professionals will now be consulted and if feedback is positive, patients could be prescribed Ibrance from April.

"Our clinical experts have told us that these types of medicines (CDK4/CDK6 inhibitors) can stop or slow down the progression of the cancer, giving people more time to spend with their loved ones," says Pharmac.

More than 2000 New Zealanders are expected to be eligible for the first and second line treatment in the first year of funding, and up to 950 New Zealanders eligible each year afterwards.

"We are here to make more medicines available for more New Zealanders," says Pharmac's chief executive Sarah Fitt.

"We do this by negotiating with medicine suppliers and running competitive pricing processes. In this instance we ran a request for proposal process and Pfizer offered the most competitive package."

At the moment the drug is not subsidised by Pharmac, meaning users have to pay the full cost themselves of more than $5000 a month.

The announcement has "delighted" the Breast Cancer Aotearoa Coalition.

"This will be a huge relief for the hundreds of New Zealand women who are struggling to self-fund this medicine," says Libby Burgess, its chair.

"Other countries have funded this type of medicine for several years now - Canada since 2016, UK and Scotland since 2017 and Australia since 2018."

Libby says a group of women with advanced breast cancer marched to Parliament in October 2018 to present a petition calling for Ibrance to be funded.

"We're pleased that this action has led to positive change, but it's a tragedy that so many of those women are now no longer with us."

A petition last year urging Health Minister David Clark to fund the drug received 50,000 signatures, and one in 2018 presented to Parliament received 34,000 signatures.

"Cancer kills one in three New Zealanders, and we need to ensure that we keep up with the rest of the world when it comes to cancer medicines," says Libby.

"New Zealanders deserve world-class cancer care, and access to modern medicines is a critical part of that. New Zealand's current medicines budget is one of the lowest in the OECD and this must change."

Pharmac says it had funded nine new medicines and widened access to 26 other in the last six months.

It announced funding for Kadcyla, another type of breast cancer drug, in October.

-RNZ.