The actress was given the heartbreaking terminal diagnosis last October, and was met with masses of support and donations from fans in a bid to find a cure.
However, Leah – who played Zoe Tate in Emmerdale – has sadly revealed that her new treatment has stopped working, but she is still determined to find a cure.
After being told her illness couldn’t be treated in the UK, Leah raised money to have pioneering immunotherapy in Germany.
She later discovered her Chinese heritage meant she was compatible for a clinical trial in the UK, and started her NHS treatment here at the end of last year.
But the 53-year-old yoga teacher’s partner Jez Hughes has told supporters on her crowdfunding page that the treatment has unfortunately failed.
He wrote: “We have found out the drug definitely isn’t working so she has been off this for a while while we find out the next steps.
“We think it probably stopped working back in March or even before. So for the last five months she has been prospering solely on the alternative treatments.
“This is due to your incredible support as these aren’t cheap. So we are so grateful for the opportunity to keep Leah strong and well. We really believe it is working.”
The 51 year old discovered symptoms weeks before her diagnosis, after she struggled to walk up the stairs.
And just days later, the star was rushed into hospital where she had to have an emergency procedure – where doctors had to remove a large amount of fluid from her chest.
The mum of two has since been diagnosed with lung cancer, which doctors have said is inoperable.
Leah was the first lesbian character on a British soap, winning Best Exit at the British Soap Awards when she left the show in 2006. She has since been teaching yoga and mediation after moving to Sussex.