The downside of drug development. It’s not always a happy ending. For some families struggling with a common cause of autism, one drug made a difference. Now it’s gone after its maker pulled financial support. Where do patients go from here? It’s a question doctors and families hope to answer.

It’s a rare moment of calm for 12-year-old Matthew Zolecki.

Melissa Zolecki, Matthew’s Mother: “We’ve known since he was twelve days old that he had Fragile X.”

And for 12 years Melissa Zolecki has patiently guided her son through the challenges of Fragile X syndrome — the most common known genetic form of autism that begins with a gene defect on the X chromosome.

Dr. Elizabeth Berry Kravis, Rush pediatric neurologist: “Patients don’t make a special protein responsible for helping brain cells to wire and connect normally. Individuals with this condition have intellectual disability and prominent behavior problems.”

For Matthew, it’s fits of aggression and anxiety sparked by simple, daily activities.

Melissa Zolecki: “Going into school, going into restaurants, at school going from classroom to classroom. Not getting his way. He would have meltdowns — fall to the ground, bite his hand, bang his head.”

There are other struggles — words are often repeated, and conversations limited. But movement is constant.

Melissa Zolecki: “You can see he’s all over the place.”

Behavioral therapy helped then a new drug entered the picture. Rush pediatric neurologist Elizabeth Berry Kravis enrolled 50 patients in a clinical trial to test the medication.

Dr. Berry Kravis: “Not everyone responds to the medication, some patients don’t do well. There’s a subgroup that constitutes what I would estimate to be about a third of patients that do very well.”

Matthew was among them. He started taking Arbaclofen in 2009.

Dr. Berry Kravis: “It helps with behavior, it helps with socialization, it helps with communication.

Unlike supportive therapies that address symptoms like attention problems or aggression, Arbaclofen targets the root of the problem in the brain – too much glutamate — an excitatory neurotransmitter that’s overactive in patients with Fragile X syndrome.

Melissa Zolecki: “I mean, the things we saw for him. We certainly saw an increase in language, more thoughtful speaking, not as much of the repetitive, same conversations over and over. But then the everyday stuff.”

Like going to the dentist — a drill that once required five adults to hold him down during a routine check. On the drug …

Melissa Zolecki: “He sat in the chair and they cleaned his teeth and I sat in the waiting room the whole time. I didn’t have to coach him. When you look at that and want to say concretely how did it help him, well there’s no test that’s going to measure that but I can see a difference.

But the FDA needs proof, and Arbaclofen manufacturer Seaside Therapeutics says their drug did not meet expectations in reducing social withdrawal – the primary goal of the study. Parents say there were other benefits.

Dr. Berry Kravis: “I have emails from families saying their child has become aggressive again. It is heartbreaking to hear the stories. I do believe the medication works.”

Melissa ran out of Arbaclofen pills about a month ago – already she sees changes in her son’s behavior.

Melissa Zolecki: “Things were never easy … but things were easier. Now they are back to a lot more of I have to really, really think ahead and plan.”

There is still a glimmer of hope — Seaside Therapeutics hopes to have results from its final Arbaclofen trial, which was conducted with younger children, by late summer. If the results are positive, the company may move forward with FDA approval.