Emma and Chris Corr, of Wansbeck Road, Jarrow, hope to be among a select group admitted to the House of Commons’ public gallery for the key session.
They want to hear what MPs have to say about the possible licensing of highly effective but ultra-expensive Orkambi on the NHS.
If barred due to seating limitations, they will join other supporters protesting outside.
The couple hope the hearing will conclude with MPs agreeing to push for the drug to come under health service funding.
They say that would lead to thousands of sufferers, including their daughter Harriet, three, gaining access to a treatment proven to have dramatic health benefits.
Jarrow MP Stephen Hepburn, who has supported their fight, is among parliamentarians lining up to speak.
English teacher Emma, 37, said: “We don’t expect anything to come of this on the day, we know the MPs won’t stand up and make Orkambi available there and then.
“The best outcome is that they decide this is an issue that must be carried forward and that further action is needed.
“I don’t exactly know what the next step would be, but I’m hopeful this debate is part of a process that will lead to Orkambi being made available.”
She added: “Other countries have come to agreements with its manufacturer over costs, so I don’t know why this country can’t.
“A number of sufferers have died in the past few weeks - it is awful to have this carrot dangled but then for stalemate to set in.”
Chris, 36, a supervisor with engineering firm Seimens, and Emma are among more than 100,000 people to have signed an online petition supporting the drug’s use.
Under government rules, that level of support automatically triggers the right for the issue to be debated by Parliament.
Through price-cutting deals with other governments, drug company Vertex has been able to make Orkambi widely available in some countries.
But it is thought to cost the NHS £104,000 per person for treatment a year, making it currently prohibitive.
Orkambi corrects faults in the lungs on a cellular level rather than just treating the symptoms of cystic fibrosis.
It works by helping water and salt pass normally out of the lungs of people with the most common type of the condition.
Vertex is understood to have approached the UK government with a proposal around pricing.
Last month, the firm confirmed it hoped to soon bring even better cystic fibrosis drugs to market.
These have the potential to make the condition chronic but manageable rather than life-shortening and terminal.
The petition can still be signed and can be found at https://petition.parliament.uk/petitions/209455%EF%BF%BD