From what I recall, this is exactly the same as selling shares -...

From what I recall, this is exactly the same as selling shares -
Selling for a profit attracts a capital gains tax and if the options or shares are held longer than 12 months, then there is a 50% reduction in CGT.
So options are no different to shares in regards to tax, whether sold as an option or exercised & converted (the share purchased) & sold as a share. Once the option to purchase is exercised & converted, then the share needs to be held for 12 months to qualify for the 50% tax reduction.
Therefore if the option is not sold or converted prior to the expiry date, then the cost of the expired options can be claimed as a capitol loss.

This is my understanding so just be mindful that there will always be a tax implication. I got caught once trying to hold for 12 months to obtain the 50% reduction, only to see a substantial profit become a substantial loss just 2 weeks out from the 12 months period when the SP took a massive nose dive.
Talk about a kick in the guts.