Or actually, this is better.
https://wiki.guildwars.com/wiki/Melandru%27s_Resilience"Elite Stance. (8...18...20 seconds.) You have +4 Health regeneration and +1 Energy regeneration for each condition and hex on you."
In the game, it can work well, but especially on hard mode, many spells and attacks deal so much damage that you can still easily get overwhelmed. That's the big paradox with guild wars .. one has to check out the enemies and their skills before clearing an area .. and i don't think that should be necessary. But, trial and error is part of any game .. so there it is. I actually made it quite far, played it many hundreds of hours.. finished all expansion packs and cleared many hard mode areas..
Guild Wars Stingray Strand Vanquish Clear Ranger Hero Team
https://www.youtube.com/watch?v=R2f6ZjJl4LkAnd the condition on topic, lol ^^ Very fitting
https://wiki.guildwars.com/wiki/Virulence"Elite Spell. Inflicts Disease, Poison, and Weakness conditions (3...13...15 seconds). No effect unless this foe already had a condition."
So melandru's resilience would be a great healing counter spell against that. But again, on hard mode, the ai usually have many other spells that deal direct damage, like shatter hex and such.
One last negative about it, is that hit point regeneration is capped at 9. So even if the calculation sometimes may not favour a great overburden of regeneration, missing out on those extra points is a negative factor.