(Reuters) -AstraZeneca ( AZN ) said on Monday it would cap out-of-pocket costs for its inhaled respiratory products at $35 per month in the United States, starting June, following a similar move by rival Boehringer Ingelheim earlier this month.

The cap would apply to all its respiratory products portfolio, including inhalers to treat asthma and chronic obstructive pulmonary disease (COPD), AstraZeneca ( AZN ) said.

Boehringer had also said it would cap out-of-pocket costs for its inhaler products for chronic lung disease and asthma to $35 per month, starting June 1.

These announcements come amid scrutiny from lawmakers such as Bernie Sanders into the high cost of inhalers that 25 million Americans with asthma and 16 million Americans with COPD use.