Abi Longfellow suffers from a one-in-a-million kidney disease called Dense Deposit Disease (DDD), which stops the kidneys from filtering waste from the blood.
A petition set up by her parents, Andy and Jo Longfellow, to get Abi, 13, the drugs she needs has been signed by more than 200,000 people.
And the teenager wrote a heartfelt letter to Prime Minister David Cameron asking for his help last year.
NHS England has now drawn up a draft policy proposing to commission the drug eculizumab, which costs £393,000 a year, to patients who meet a set criteria.
Mrs Longfellow, from Robin Hood, said: “This is a significant step forward after eight long months of campaigning. We have been overwhelmed by the support we have received.
“Abi had a massive smile on her face when we told her and the consultant is very confident she will be given the drug. They are now writing up her post transplant protocol.”
NHS bosses are due to publish the final policy in March.
Mrs Longfellow said: “We are not celebrating yet but it could make history for patients like Abi if it is approved.”
NHS England refused to pay for the drug because Abi’s condition is too rare to be covered by the national funding policy, but not rare enough to qualify as an exceptional case.
And in a cruel twist, eculizumab is kept under lock and key at Leeds General Infirmary where she is treated.
If the drug is commissioned, Abi would undergo a kidney transplant and eculizumab would help ensure her new organ remains healthy.
A NHS England spokesman said: “We have prepared a new draft policy on eculizumab which we are now consulting on.”