Nineteen patients with genetic emphysema are to continue receiving a key medication for life after the HSE reached agreement with the manufacturer on its provision.
However, the deal came too late for two other patients who died after the treatment was removed last because of a pricing row.
It also does not apply to another 40 patients who were not part of the original compassionate use programme but would benefit from the treatment.
Under the agreement, manufacturer CSL Behring will continue to supply the medication, Respreeza, to the patients with Alpha-1, or genetic emphysema.
The two patients died while off the treatment in 2017 when the supply of the therapy was stopped for a six-week period, according to the Alpha-1 Foundation.
Respreeza, which is available in 12 European countries but not Ireland, is linked to a decrease in the frequency and severity of chest infections and resultant hospital admissions.
New patients requiring the drug will not be able to avail of it until CSL Behring submits a new proposal for price reimbursement to the HSE. The original one was rejected on cost efficiency grounds.
"Today's decision brings to an end a hugely stressful and difficult time for these 19 patients and for the families of the late Anna Cassidy and Marion Kelly who campaigned for over a year for approval of Respreeza," said Geraldine Kelly, chief executive of Alpha-1 Foundation Ireland.
The family of a Co Tipperary woman, who died just under a year ago after the drug was withdrawn, said the agreement reached by the HSE and the drug manufacturer to make it available again indefinitely was hugely welcome but bitter-sweet.
The family of Marion Kelly (53), from Nenagh, expressed relief “that the common sense denied Marion has now at last prevailed”.
The family spent the 12 months since her death leading a campaign to secure the long-term provision of the drug and have said today that the positive outcome means that her death was not entirely in vain.
Ireland has among the highest prevalence of Alpha-1 Antitrypsin Deficiency in Europe. About 3,000 people have severe Alpha-1 on the island of Ireland, with up to 250,000 people with a milder form of the condition at increased risk of lung disease, particularly if they smoke.