"Rules adopted in four states since last year cap what insurers can charge patients out-of-pocket for expensive medicines -- typically, to $150 a month. Similar legislation is under consideration in at least nine other states ... driven in some cases by patient-advocacy groups supported by companies like Pfizer Inc. under a campaign called Cap the Copay. If successful, the lobbying may short-circuit health insurers' attempts to persuade drug companies to moderate their prices."