U.S. Rep. Elizabeth Esty just helped prevent devastating cuts to the prescription drug coverage that over a quarter million Connecticut Medicare beneficiaries depend on. She deserves our deep gratitude.

Earlier this year, the Centers for Medicare and Medicaid Services (CMS) introduced “reforms” that would have decreased access to a whole range of medications covered by Medicare’s prescription drug benefit, known as Part D.

Fortunately, Esty and her colleagues blocked the new rules and persuaded the administration to take them off of the table. But similar changes targeting Part D are almost certain to pop up again. CMS Administrator Marilyn Tavenner has already announced plans for “advancing some or all of the changes . . . in future years.”

The proposed rules would have eliminated immunosuppressants, antidepressants, and antipsychotics from Part D’s list of six “protected classes” of drugs. Had these reforms passed, countless beneficiaries would have found their health — perhaps even their lives — at risk.

Altering the coverage of these six classes of drugs would place some of our most vulnerable populations in jeopardy. Patients rely on these types of medications to maintain their daily lives. The medications require a strict adherence and dosing schedules. Anything that would disrupt these routines could cause debilitating setbacks.

Not only were the six protected classes at risk, but the CMS proposed rule would also restrict plan options for seniors. Part D sponsors would only be permitted to offer two plan options per region. An analysis by the Avalere group suggests that such a rule would result in the elimination or consolidation of a full 40 percent of enhanced plans by 2016.

To keep Part D working well, Washington lawmakers must remain vigilant and keep fighting against proposals to gut the program. Part D is too important — not just to seniors here in Connecticut, but to Medicare beneficiaries all across America.

Medicare Part D took effect in 2006 and has proven its worth year after year. Its competitive, market-based design continues to be key in providing a wide variety of low-cost plan options.

Consider that in Connecticut, nearly half of all plans offered under Part D have no deductible. Premiums start at just $15 per month. And these lower costs don’t mean lower quality coverage. Savings are real and significant. Studies have shown that in the United States as a whole, more than 6.6 million Medicare beneficiaries have saved upward of $7 billion thanks to Part D coverage.

Moreover, better access to prescription medications decreases overall healthcare expenditures. Harvard researchers found that after Part D’s implementation, non-drug medical spending dropped $1,200 each year for patients formerly covered by limited drug plans. After the first full year of the program, Part D savings reached $13 billion.

With all these positives, it’s no wonder Part D has a 90 percent approval rating among enrollees.

Part D has also been a bargain for taxpayers. Overall Part D costs are 43 percent — or roughly $350 billion — less than initially anticipated by the CBO.

In light of Part D’s success, CMS’s attempt to “fix” the program doesn’t make sense.

Cutting back on plan options would essentially undermine what has made Part D so successful — its market-based structure. An open-plan design fosters competition between providers, incentivizing these plan sponsors to offer the best coverage at the lowest possible price. In fact, a recent CBO analysis found that between 2007 and 2011, providers offered lower bids in areas with more plan sponsors.

She may not have won a national championship, but Congresswoman Esty and her fellow policymakers just scored a huge victory for America’s Part D beneficiaries.

Shawn M. Lang is the director of public policy at AIDS Connecticut.