When will leave to amend a Complaint for failure to state a claim be granted?

When a complaint is dismissed for failure to state a claim, leave to amend should be granted unless it can be determined that no possible amendment would cure the complaint's deficiencies. Reddy v. Litton Indus., Inc., 912 F.2d 291, 296 (9th Cir.1990), cert. denied, 112 S.Ct. 332 (1991). Moreover, an "amended complaint may only allege other facts consistent with the challenged pleading." Id. at 297 (quotation omitted).