In the lab: David Kass, left, and Nazareno Paolocci

David Kass

“HNO was doing this in a different way, and one that looked like it would be safer and more synergistic with other heart failure therapies.”

Sometime in the summer of 2000, Nazareno Paolocci, then a postdoc in the cardiology division of the school of medicine, walked into the office of his faculty mentor, David Kass, to show him some curious data he had collected. Paolocci had been experimenting with a compound called Angeli’s salt, a white, powdery substance that when mixed in aqueous solution releases a molecule called nitroxyl, or HNO. Paolocci had discovered that when he injected a solution of the salt into dogs, their hearts’ contractility, or pumping power, increased, and their veins and arteries dilated, making it easier for their hearts to work.

Kass, who was known around the department as a “heart failure guy” for his work in probing dysfunctional hearts and therapies that might improve them, wasn’t impressed. He had never heard of HNO or Angeli’s salt before, and the improvement in heart function noted in Paolocci’s experiments could have been due to any number of things. “I had certainly seen many drugs that increased contractility before,” says Kass. “This did not seem like it was going to be a rip-roaring effect from what I was seeing in the data. But I didn’t tell him, ‘Under no circumstances are you to do this again.’ Rather, I suggested he rule out some likely confounding factors first.”

 So, as a sort of side project, Paolocci conducted his experiment again. And again. Each time, he increased the sample size, ruling out some of the issues Kass had raised. Some time after, Paolocci started recording the same positive results in dogs with heart failure, and Kass became a believer as well.

Last fall, the two researchers and their business partners sold Cardioxyl Pharmaceuticals, the company they co-founded based on Paolocci’s original investigations, for $300 million to Bristol-Myers Squibb. The total deal could top $2 billion depending upon future development, regulatory and sales achievements of Cardioxyl’s CXL-1427, an intravenous treatment for late-stage heart failure known as acute decompensated heart failure (ADHF). The condition’s symptoms include edema, fatigue and shortness of breath, which often leads to hospitalization.

Through early clinical trials, Cardioxyl demonstrated that CXL-1427 improves how the heart muscle relaxes and contracts without the complications incurred by current treatments, which frequently produce an increase in heart rate, oxygen consumption or both. Other drugs used for heart failure have been known to restrict blood flow to parts of the body or cause severe arrhythmia.

CXL-1427, which has completed phase IIa clinical trials to evaluate efficacy and safety in selected populations, could provide hope for a condition that contributes to one in nine deaths annually, according to the Centers for Disease Control and Prevention.

“A lot of drugs in the heart failure field fail because they tackle just one aspect of a multisided kind of disease,” says Paolocci. “It’s something that is affecting too many things at the same time. With HNO, the whole thing was very different. We were not facing an agent doing only one thing; it was doing at least two or more. You had its relaxing effects on arteries and veins, but also an increase in contractility of the muscle. I had shown this second part was not because of reflexes that are activated when blood pressure falls but because of a direct effect. That was the sparkling point that told us we might be facing something different here.”

“There were combination dilator/contraction-enhancing drugs before, so this part alone was not the be-all for HNO,” notes Kass. “But HNO was doing this in a different way, and one that looked like it would be safer and more synergistic with other heart failure therapies.”

But the road from concept to compound has not been without its challenging hurdles. In fact, right when everything seemed to be going along smoothly, it nearly all came to an unexpected end.

It was an Italian chemist named Angelo Angeli who published the first study about nitroxyl in 1901. But Angeli, a contemporary of Albert Nobel, whose chemically similar explorations involving nitroglycerin literally exploded around the world, was a notorious recluse and did little to promote his discoveries. (Angeli was reportedly so shy that when the Italian government tried to award him for his efforts in developing a gas mask for the Italian army, he requested his prize be a suspension from all academic duties involving teaching and public speaking at his university in Florence.) 

Nearly 100 years later, Paolocci, another Italian-born and educated scientist, became acquainted with HNO when a researcher at the National Cancer Institute named David Wink introduced him to Angeli’s salt. Paolocci had read about the possible vasodilation properties of HNO in several decade-old papers, yet few researchers were studying it. It’s discouragingly difficult to generate and hard to detect, and ultimately reacts with itself, forming water and nitrous oxide, more commonly known as laughing gas. “In a way, it was good that nobody was chasing the same issue, so we were in no rush from competitors,” says Paolocci. “It allowed us to finish our papers calmly—and we never had trouble publishing the results.”

After publishing two well-received papers in 2001 and 2003 in the Proceedings of the National Academy of Sciences on the effects of HNO on dogs with both normal and failing hearts, Paolocci and Kass realized they might be on to something. They, along with several pioneers in the HNO field, including Wink, patented the concept in 2004 and began thinking about forming a company to develop a compound for human use.

But there was a major problem with using Angeli’s salt in clinical treatment: The compound is notoriously unstable and short acting. “When the company was founded, we realized Angeli’s salt wasn’t druggable,” says Kass. “To have a drug you’re going to administer to a patient, you have to have something you can stick in a medicine bag and let it drip into someone’s IV. If you have to change the bag every 10 minutes because this stuff deteriorated or decomposed, that is not a viable option. It’s perfectly good for acute experiments but totally useless as a drug.”

What the researchers needed was a more effective donor—or prodrug—than Angeli’s salt, which acted as a Trojan horse in delivering HNO once it entered the bloodstream. They needed one that would release the proper amount of nitroxyl in a stable, reliable manner. Unfortunately, nothing like that existed.

Not long after Paolocci and Kass patented their concept, Wink gave a talk at a chemistry colloquium organized by John Toscano, a professor in the Department of Chemistry at Johns Hopkins’ Krieger School of Arts and Sciences. It just so happened that Toscano had recently become fascinated with Angeli’s salt—as well as its limitations—and was working on synthesizing other HNO donors that were easier to work with. As Toscano recalls: “Dave Wink said to me, ‘Do you know these folks down in your medical school? They’re looking at effects of HNO on heart function.’ I had no idea. They were doing the physiology. We were doing the fundamental chemistry, and once we hooked up, there were lots of dots to [connect].”

Soon after Toscano joined the research efforts, Christopher Kroger, a venture capitalist from Aurora Funds in Raleigh, North Carolina, and then Peter Suzdak and Reza Mazhari, two pharmaceutical company veterans, approached the Johns Hopkins Office of Technology Transfer (now known as Johns Hopkins Technology Ventures) to inquire about any promising business opportunities. The office hooked them up with Paolocci, Kass and Toscano, and in 2005, Cardioxyl was born.

“[The story here] is that big pharma has reduced its R&D capabilities and increasingly looks for startup companies to develop and de-risk technologies it can take on by acquisition,” says Neil Veloso, Tech Ventures’ executive director for technology transfer. “That’s where Tech Ventures comes in. We can look to either license the technology to pharma, or the more immediate step would be to create new companies based on the technology a researcher discovers. Part of that new company creation involves identifying appropriate venture capital investment, like what we saw with Cardioxyl.”

The team developed an ambitious business plan that called for the creation of a potential drug by the end of 2006. Clinical trials were expected to start three and a half years later. Despite the lack of an actual drug, the promise of one was convincing enough that the venture capital began to flow in, eventually reaching more than $65 million.

With an influx of money, the company was able to outsource its research and development to a drug development firm in Europe. Cardioxyl continued as a side venture for the Johns Hopkins researchers, who primarily served in advisory roles. Paolocci worked closely with Toscano, who would conceive potential groups of compounds to test, while the lab in Europe conducted the experiments, relaying the data back to the U.S. By 2009, right on schedule, a new, more stable prodrug went into clinical trials.

And then disaster struck.

Several months into the trials, redness began appearing on test subjects’ arms at the site of injection of the drug. Something was wrong; the trials were stopped.

“It was like a come-to-Jesus moment,” recalls Kass. “We thought, ‘Are we going to do this? Is this it? Is it, everyone gets one bite at the apple and you’re done?’ But there was conviction throughout the company that we could get through it.”

With its clinical trials suspended and funding dangling by a tenuous thread, Cardioxyl decided to start anew. Researchers hypothesized their compound was modeled maybe too much like Angeli’s salt. It acted too quickly. The Trojan horse—the prodrug that was injected into the bloodstream before releasing its supply of HNO—was unloading its cargo too quickly and all in one spot, causing inflammation and thrombosis at the site of injection.

After a year of additional work, researchers came up with a new compound. After receiving FDA approval, in newly launched clinical trials, the drug, now known as CXL-1427, proved to have an even greater effect on contractility and vasodilation than the original drug—and it didn’t show any toxicity.

With the trials back on track during 2011 and 2012, it was time for the brain trust at Cardioxyl to consider its next move. Should the company attempt another round of venture capital funding—researchers had started to test an oral form of an HNO prodrug on dogs, an undertaking that would require tens of millions more in funding—launch an IPO … or find a buyer?

 After discussions with several pharmaceutical companies, Bristol-Myers Squibb, which lacked a significant heart failure medication in its portfolio, emerged as the strongest suitor. “The acquisition of Cardioxyl strengthens Bristol-Myers Squibb’s heart failure pipeline with a phase II asset that has the potential to change the course of the disease rather than simply treating the symptoms,” Francis Cuss, Bristol-Myers Squibb’s chief scientific officer, said last fall.

For Kass, Paolocci and Toscano, all of whom will likely serve on a Bristol-Myers Squibb advisory board of some sort, it was an affirmation of years of work—if not a financial windfall. Since their shares in the company were so heavily diluted during the rounds of venture capital funding, the Johns Hopkins researchers won’t be retiring as millionaires anytime soon. But they remain invested in seeing the project through to completion.

“We beat the odds multiple times,” says Kass. “But the good stuff still has to come. There needs to be more testing to prove it actually works in a meaningful way in patients. If it does work, then this will be a great success. So long as we give it our best shot and move forward carefully so any failure is not due to our own mistakes, the rest will be up to HNO and our molecules. ”

If the drug does prove effective in further trials, Kass sees the potential of the intravenous version being used in tandem with a pill. Patients suffering from ADHF would receive the drug intravenously in the hospital and then go home with a supply of the pills—potentially saving some of the $34 billion that’s spent annually on heart failure-related hospitalizations. “We’ll be looking to see if there is a more sustained, bell-ringing effect,” says Kass. “If you can reduce rehospitalization significantly with that kind of a protocol and show that this combo will keep patients out of the hospital at a much higher rate over a six-month period or longer, that’s a win. A huge win.”

Of course, Kass says, the ultimate goal would be a drug that could combat heart failure before it even reaches the acute stage—something HNO might have the potential to do.

Meanwhile, Paolocci and Toscano continue to collaborate on investigating the chemistry and biology behind the molecule, which has become a burgeoning field of inquiry, with dozens of new papers published by research groups around the world. Paolocci, for one, is still amazed that something he began almost as a lark 15 years ago has spawned a potential therapy for a condition that historically has been so challenging to treat.

 “To be honest, I always had the hope inside,” he says, “but I kept it silent. In the heart failure field, you see 100 compounds get into clinical trials, and you see 99.9 of them for one reason or another fail. The idea that somebody will take this to the very end and say it’s good or not good, that’s what I am looking forward to. For me, it will hopefully be a positive ending to a very long story.”

Nazareno Paolocci

“In the heart failure field, you see 100 compounds get into clinical trials, and you see 99.9 of them for one reason or another fail.”