Ensuring Access to Lower-Cost Medicines for Seniors Act This bill requires prescription drug plans under the Medicare prescription drug benefit to include generic drugs and biosimilars on their formularies. Specifically, the bill requires plans that use formularies to include generic drugs and biosimilars on the formularies and without any requirements (e.g., prior authorization requirements) that are more restrictive as compared to those for brand-name drugs and biologics. Plans that use cost-sharing tiers must also have specific tiers for generic drugs and biosimilars, in accordance with certain limitations.