Multiple sclerosis is an autoimmune disease that tends to strike young people, usually between their 20s and 50s, with unpredictable and often disabling symptoms. The immune system attacks the coating around nerve fibers, hampering the system's ability to communicate -- resulting in symptoms ranging from blindness to fatigue to paralysis.
The progress, severity and specific symptoms of MS in any one person cannot yet be predicted. Though symptoms may not be permanent, each relapse leaves the body worse off.
At least two to three times more women are diagnosed with the disease than men. MS affects more than 2.3 million people worldwide.
Source: National Multiple Sclerosis Society
The strange pains would attack without warning, almost as if they were changing with the weather.
And every time they hit Katy Mena - a young twentysomething, seemingly in her prime - it was something different. An unshakable cold in her legs. Double vision. Tingling pain in her limbs. A tight, squeezing sensation around her torso, like an unwelcome hug.
Sometimes a leg would go limp, or she suddenly couldn't use her arm. Some days she would feel electric shocks all over her body.
For nearly a decade, Mena, now 32, battled the progression of multiple sclerosis with treatments that couldn't seem to do much to keep its devastating effects at bay.
"MS is such an invisible disease," she explained. "You can't see if somebody's seeing two of everything. You can't see if someone feels like their flesh is being ripped off with hot knives. You just can't see these things."
For the longest time, Mena herself had a hard time understanding the disease.
The photos she flips through of her mother, Vicky, show a woman whose warm, wide smile and easy laughter bear no trace of the decades of pain she, too, suffered with the disease.
And for many who know the vibrant Greek-American Signal Mountain clan -- which Mena describes as "just like what you see in 'My Big Fat Greek Wedding'" -- the MS has been easy to overlook.
But the disorder has left a deep mark on the Menas. Katy's mother died from complications of the disease in January after battling it for more than 30 years -- many of which did not include treatment.
Katy Mena's disease is taking a different route than her mother's did early on. Katy and her physician say that's because of treatment with an experimental drug called Lemtrada.
In the past six years, the drug has stemmed the strange and painful relapses that damaged her nervous system, and appears to have checked the disease's progression.
Nothing has worked as it has, she says.
That's why, when Katy Mena found out -- just a few days after her mother's death -- that the U.S. Food and Drug Administration had rejected Lemtrada for the market, she was shocked and dismayed.
"I really believe that [Lemtrada] has saved my life," she said.
"And I believe that if it had been available in those first years that my mom wouldn't have passed away as young as she did at 59. I don't know why we would withhold having access to this treatment."
BATTLING THE INVISIBLE
For Katy Mena, the fight with the disease started with a slight tingling in her hand.
A few weeks later, she was having dinner with her family when she turned to look at her sister, Alexia, and saw two of her.
When she told her parents, they were alarmed. Vicky Mena's double vision in the 1970s was the first sign of a disease that would not be formally diagnosed until the 1990s.
Back then, treatment options were scarce or non-existent.
It seemed unthinkable that the Menas' daughter could have the same disorder. At that time, there was no clear hereditary link.
But an MRI a few weeks later confirmed their fears: Katy also had MS.
Her first treatments in 2001 involved giving herself a shot every day or two.
A few years later, she and her mother began driving to Cullman, Ala., to see neurologist Dr. Christopher LaGanke. He treats about 2,000 MS patients at a center named after his mother, who also died of complications from MS.
The doctor saw that Katy's disorder was progressing much faster than the typical MS patient.
"She was looking at very significant disabilities within just a few years," LaGanke said.
In 2008, LaGanke told her about clinical trials for Lemtrada. It wasn't a cure, but it could potentially halt the disease's progress.
Lemtrada is a form of chemotherapy, LaGanke explained. Antibodies bind to the outer circuits of key cells -- the cells that wreak havoc on the nervous system -- and destroy them.
When the bone marrow remakes the cells, the immune system is reprogrammed.
Sixteen patients at La-Ganke's center were involved in the trial.
Katy Mena started the grueling treatment in 2008: Eight hours of IV infusion for five days in a row one summer, then another three days of the same treatment one year later. While most patients needed only two infusions, Mena needed three.
But after her recovery, she says she feels the best she has since the disease set in. She still feels pain and fatigue, but not nearly at the same scale.
"I started to get better, and I've felt really good since then," she said.
She married on New Year's Eve two years ago. She's a writer and works in public relations. She keeps up with two large dogs. She does yoga five days a week.
LaGanke said most of his patients have shown similar improvement. Five years after the treatment, 80 percent of all the people involved in the trial have not needed any further treatment, he said.
"No MS trial has had the mean patient better at the end of two years of the trial," the doctor said.
Dr. Jack Burks, chief medical officer with the Multiple Sclerosis Association of America, has said the drug "has the potential to be a major contributor in the fight to manage MS."
While her own health deteriorated, Vicky Mena remained a fierce cheerleader for her daughter.
"We were already really close, but it was just another way for us to be closer, for me to truly empathize with what was happening with her," her daughter says.
But Vicky Mena's disease, largely untreated and left free to damage her system for 20 years, got much less benefit from Lemtrada. She grew worse, needing to use a walker, then a scooter, to get around.
One Monday night in January the mother and daughter talked, making plans for lunch the next day. Two hours later, Katy Mena got a phone call from her brother.
Her mother had died. The family believes it was a pulmonary embolism, a complication of her MS.
At the funeral home a few days later, people started lining up to pay their respects at 4:30 p.m. The line didn't peter out until six hours later.
Not long after, the FDA rejected Lemtrada for the market even though an FDA committee had recommended approval just a month before.
"I was angry," said Katy Mena. "My mom had just died. I know that it had saved my life up to this point. ... If we have the technology and we have the resources, why would we withhold something that is so effective in this disease?"
According to a news release from Genzyme, the company that makes Lemtrada, the FDA decided that more clinical trials would be needed before the drug's final approval.
"This is disappointing news, given the need for more therapeutic options for people with MS living in the United States," said Timothy Coetzee, the chief advocacy and research officer at the New York City-based National Multiple Sclerosis Society.
"Lemtrada is already approved within the European Union, Canada and Australia. These approvals were made from the same data that were submitted to the FDA for approval in the United States," Burks said.
The MS Society has since surveyed MS specialists and found that 77 percent of the physicians who responded "disagreed or strongly disagreed" with the agency's decision.
LaGanke said the FDA's decision left him "disappointed and infuriated."
"Patients with MS need more choices," said LaGanke. "There are still unmet needs."
While doctors involved in the study have acknowledged that Lemtrada can cause thyroid problems, low platelet counts and infusion reactions, the FDA has said its chief concern is with the clinical trial's design.
The format did not meet the agency's standard requirement of double-blind, placebo-controlled drug trials -- where some patients unknowingly receive placebo treatments from their equally unknowing doctors.
In this case, a double-blind test involving a placebo would not have been effective, doctors like LaGanke argue, and they say the FDA was aware of the study's structure from the start.
Lemtrada and other MS treatments have very noticeable side effects that would make it easy for participants to know if they were on a placebo. Advocates argue that the same model used for Lemtrada has been used in trials for other MS drugs that were approved.
They also worry about a possible spike of "medical tourism" among Americans with MS.
"Interested patients with means are likely to travel to countries where the product is available but lose the close monitoring required for its use," said Arney Rosenblat, associate vice president of the MS Society.
The FDA does not comment on drugs under review. Genzyme plans to appeal the decision and is conducting an extension of the study.
Mena is still being monitored, but the situation upsets her.
"To know people won't have this as an option is horrifying to me," she said.
She plans to continue to push for expanded MS research and treatment options. She doesn't want the disease to be her main focus -- something she said her mother taught her.
When she thinks of her mother, she doesn't think of a long-term MS patient.
She thinks of a woman who trekked through Greece and Paris and Mexico. A woman who spearheaded committees, loved Greek dancing and was deeply devoted to her studies of the Orthodox faith. A wife and mother.
"She lived with [MS] and she fought against it, but that wasn't who she was," Katy Mena says. "They lived their life. And when I was diagnosed, she said the same thing to me. 'Live your life.'"
Contact staff writer Kate Harrison at firstname.lastname@example.org or 423-757-6673.