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As a physician for more than 35 years with a large multiple sclerosis practice, I am more than familiar with the increasing challenges my patients face in accessing their critical treatments. And the Nov. 11 Economy & Business article "Pricey specialty drugs force seniors to make hard choices " accurately highlighted the incredible dilemma faced by seniors on Medicare who need expensive specialty medications to treat their illnesses. Access to medically necessary health care is critical for successful patient outcomes, yet it is often impeded or blocked by unaffordable deductibles, co-payments and co- ­insurance. For many Medicare beneficiaries, there are no limits on the amount of cost sharing.

However, the article left out an important part of the equation: Independent charitable patient- ­assistance foundations offer a critical safety net to the Medicare population and other underinsured individuals by paying for a portion of their out- ­of-pocket costs. Until there is a systemic fix to the problem of underinsurance, patient-assistance programs will continue to play an essential role in ensuring that hundreds of thousands of patients get the care they need.

Donald A. Barone, Washington

The writer is chairman of the Patient Access Network Foundation, a nonprofit funded in part by pharmaceutical companies that helps people pay for the out-of-pocket costs of their medications.