Lauren Sullivan is battling to get health insurance approval for a gene therapy for her daughter.

When a $2.1 million gene therapy offering the chance of a cure for her daughter's rare disease won government approval in May, Lauren Sullivan was struck by a sense of "dangerous hope.''

But after UnitedHealthcare said it would not cover the treatment, Sullivan's hope has given way to an anxious race against the calendar.

The Food and Drug Administration said the new drug, which works by replacing the defective gene that causes Daryn's spinal muscular atrophy with a good one, must be administered by age 2. Daryn's second birthday arrives in early October.

With time running out, the family is caught in a battle over who gets treated with a cutting-edge drug that is also extraordinarily expensive.

The outcome, which raises uncomfortable medical, financial and ethical questions, carries deep implications for access to future gene therapies.

Numerous gene therapies are under development for a range of diseases, but the supercharged prices pharmaceutical companies are expected to demand will thrust doctors and patients into epic showdowns over costs.

Lauren Sullivan makes dinner as Daryn washes her hands at their home in McLean, Va. on July 5.

Zolgensma - the gene therapy for SMA - is the first big test case, and Sullivan said she feels powerless in a tussle between health-care giants.

"There's a lot of screaming into the void around here,'' Sullivan said as she pored over the fine print of UnitedHealthcare's Zolgensma coverage policy while working on an insurance appeal in the bedroom of her home in McLean last week.

On one side is Novartis, the drug giant that set the record $2.1 million price when it began marketing Zolgensma in late May; on the other is UnitedHealthcare, which is among insurance companies that are drawing up coverage policies to guide who will get the advanced treatment and who will not.

Sullivan blames UnitedHealthcare for its coverage denial, but also Novartis for setting a prohibitively high price.

"If a patient needs something, especially a baby, and her doctor prescribes it, and her parents agree that she needs it, you should be able to get it,'' Sullivan said. "But I feel that it's wrong to just price a drug as high as you can, because you can. So I'm very conflicted.''

SMA is caused by a genetic deficiency that causes nerve connections to die off, leaving the patient with an inability to control muscles. The most common form of the disease, Type 1, is also the worst, and leaves infants unable to sit up, breathe or eat. They typically die, and if they don't, they must be kept alive by respirators and feeding tubes. Type 2 and Type 3 forms of the disease are milder but still serious; Type 4 affects adults.

Daryn, 21 months old, has the milder Type 3 form of SMA, which has an estimated incidence per live birth of 13 percent. She can walk, breathe and eat on her own. She has some limitations in walking.

For purposes of insurance coverage, Daryn's relative good fortune has counted against her, because she apparently has been deemed not sick enough to qualify, Sullivan said.

The family's experience is reflective of a partially restrictive approach to coverage by insurance companies in the second month since Zolgensma won approval, according to a financial analysis released last week.

The FDA approved the drug for children under 2 with all forms of the disease, but a number of insurance companies are limiting coverage more tightly, said the report by Bernstein analyst Ronny Gal.

Gal based the analysis on a survey of 30 top U.S. insurers. Some are limiting coverage to only Type 1 SMA cases, and some limit it to children under 6 months old. The tally of defective or missing genes needed to qualify also varies by policy. That means children with the worst form of the disease are getting the therapy, but children with less severe forms may not.

"By making coverage choices that may be legally defensible but deny Zolgensma to patients who could clearly benefit, the payers are sending a clear signal that they are very unhappy with the price of Zolgensma,'' Gal wrote.

Two of the largest companies in Gal's survey, UnitedHealthcare and Anthem, suggested they are writing coverage guidelines based on clinical trial evidence, not the broader FDA approval.

"We will continue to provide access to Zolgensma in accordance with the emerging clinical evidence for treating spinal muscular atrophy,'' UnitedHealthcare said in an email. United covers the treatment for children until their second birthday. Anthem cuts coverage off after 6 months of age.

"Anthem criteria are aligned with the ages, medical conditions and other clinical characteristics of infants evaluated in clinical trials for whom there is published medical evidence to assess safety and efficacy,'' Anthem said in a statement.

The health insurance lobby America's Health Insurance Plans (AHIP) said it could not comment on individual coverage decisions by member companies, but in general it said insurance companies are a crucial defense against exorbitant pricing by drug companies.

"The problem is the price - a therapy is useless if no one can afford it,'' said Cathryn Donaldson, an AHIP spokeswoman. "We want to encourage this type of innovation but must also recognize the need to balance innovation, accessibility and affordability.''

Novartis said it was confident insurers will recognize the benefits of Zolgensma and cover the drug. Novartis bought AveXis, the company that developed Zolgensma, for $8.7 billion in 2018.

"We are pleased with the way payers are writing and implementing policies,'' Novartis said.

Zolgensma is supposed to be a permanent, one-time fix, although it is so new no one knows whether its benefits will last throughout a patient's life. It competes with an SMA therapy made by Biogen called Spinraza, which costs $750,000 for the first year and $375,000 a year after that, and requires spinal injections at four-month intervals for the patient's entire life.

Spinraza was approved in 2016, just a few months before Sullivan learned she and her husband, Kevin Sullivan, had passed SMA's defective genes down to their unborn baby.

Lauren Sullivan spends time with her daughter Daryn at their home in McLean, Va., on July 5.

Lauren, a consultant from a military family, and Kevin, a finance manager from Long Island, met in 2012 at Solly's Tavern in Washington. They married in 2015 and are now both 34.

The discovery that their baby would have SMA led to hard conversations and "many tears,'' Lauren said. They opted to continue with the pregnancy, a decision made easier because Spinraza offered the baby a chance of an effective treatment, she said.

"We just kind of knew it is going to be a different life than what we first thought.''

Lauren went into labor with an action plan; emails to doctors, the insurer, her employer and others were sent a little over two hours after Daryn arrived. Daryn received her first Spinraza treatment.

Daryn cannot be sick when she is put under general anesthesia at Children's National Hospital for her three-times-a-year Spinraza infusions. So the family undergoes a two-week quarantine period before each treatment.

Daryn also cannot show any signs of decline in motor function, or else she will no longer qualify for Spinraza coverage, Lauren said. She monitors the child's every developmental milestone for signs of trouble. So far, Daryn has trouble running and for a while had problems rolling.

"It's extreme pressure and constant, relentless fear. You have to keep showing gains,'' she said.

Zolgensma's one-time treatment would be far more desirable than the Spinraza regimen, she added.

"Daryn is an ideal candidate for this medication, because it could be a cure for her,'' she said. "She may not have to be in physical therapy for the rest of her life.''

Lauren has communicated with other SMA families on Facebook, some of whom are in a similar predicament.

Rajdeep Patgiri's 10-month-old daughter, Tora, has also been denied Zolgensma by UnitedHealthcare. Patgiri and his wife, who were living in London, found out Tora had SMA a few months after she was born, when she was not moving her legs.

"I just did a quick Google search, on 'baby doesn't move her legs,' and the first result that came up was spinal muscular atrophy,'' said Patgiri, a financial asset manager. The family moved to Ohio to be close to the site of a clinical trial for Zolgensma at Nationwide Children's Hospital in Columbus, where the drug was invented.

Once the FDA approved Zolgensma, Patgiri tried to get insurance approval for commercial purchase of the drug. Tora could get the drug intravenously that way, reaching more muscles, Patgiri said, rather than a direct injection into the central nervous system, which is the method in the clinical trial.

UnitedHealthcare denied the claim with little explanation, even after speaking with Tora's doctor, so Patgiri is appealing. Tora is not on a ventilator. She can eat solid food. She sits up and plays in her crib.

"We don't give up, so we keep fighting'' after the denial, he said. "It takes a lot to get back into fighting mode, but there is no other alternative, really.''