She said FDA inspection processes and enforcement rules have not changed.

"What has changed is that there is an aging manufacturing infrastructure, and there are serious quality problems that have required companies to close down to fix the problems."

On Monday, the FDA issued a letter to Rep. Elijah Cummings (D-Maryland) of the House Oversight Committee, responding to the committee's blaming the FDA for the shortages. The letter reiterated the report was false and emphasized the FDA is part of the solution.

What happened with Doxil

While Doxil is not a generic drug, it was manufactured by Ben Venue Laboratories, one of the country's four largest producers of generic injectables.

The Ben Venue lab was the sole manufacturer of Doxil in the nation. It voluntarily shut down in November 2011.

A May 2011 FDA inspection found a string of problems, including inadequate oversight and metallic particle shards in some of the drugs produced on site.

A November 2011 FDA inspection found additional problems, including finding a 10-gallon can in a storage area that contained urine.

In a statement sent to CNN after it shut down, Ben Venue labs said its team "has been working around the clock to implement changes needed to ensure a more sustained supply of the medicines we produce and to address the manufacturing-related issues at our facility noted in recent inspections by the FDA and other global regulatory agencies."

However, Ben Venue maintained that none of the Doxil supply was affected.

From their findings, the House Oversight Committee found that 58% of the drugs on the shortage list were produced at facilities cited by the FDA. They also found that the FDA's warning letters increased 156% from 2010 to 2011.

Dr. Scott Gottlieb, former FDA deputy commissioner, said the FDA isn't concerned about the outcome, though.

"They go in, they inspect facilities and then they issue findings. You're not asked to worry if there's a stable supply. You're asked to make sure the facility falls in line."

But Kweder says it's quite the opposite. "Well, it's our job to worry about it in our drug shortages team. When we issue warning letters today, we ask companies to very specifically communicate with us how they plan to address the problem, so we can assess what the potential of a shortage is, " she told CNN.

Kweder also cited the recent reauthorization of the Prescription Drug User Fee Act as a key to preventing shortages.

Signed by President Barack Obama earlier this month, the act will help the FDA expedite the drug review process, particularly for drugs in shortage. It will also require companies to notify the FDA if they anticipate an interruption in production.

"It allows us as a regulatory agency to step in, and try and prevent the shortage in the first place," Kweder said. "So for example, we can go to other companies to ask them to increase their production. We can assist companies that are having difficulties to finding alternatives for the difficulties they are having, and even in rare cases, we can seek sources of medications from other countries, where they might be being produced to our standards."

Help comes from abroad

That's actually what happened in the case of Doxil.

In February, the FDA stepped in and allowed the importation of Lipodox from an Indian manufacturer, a possible therapeutic alternative. But Naumann said he was never able to get his hands on it.

"The key is having enough notice," says Kweder. Since Obama signed an executive order requesting early notification from manufacturers in November 2011, more and more companies have been able to give the FDA the needed heads-up.

"We've done that successfully innumerable times. Just since January, at our count, we've prevented 94 to 100 shortages, things the public never sees," Kweder told Gupta.

"I think it's a start," says Naumann, but it's not enough.

"I think these shortages are going to continue because of the same problems that we have. There are certainly fixes out there for it. I don't think these shortages are going to go away because of this bill."

For Mosier's daughters, it's all too late.