More optimistic than ever, CHDI head scientist sees unprecedented mobilization in the fight to treat Huntington’s disease

 

In the wake of last week’s 20th Annual Huntington’s Disease Therapeutics Conference, the chief scientific officer for CHDI Foundation, Inc., declared that HD scientists had mustered unprecedented efforts toward therapies (treatments).

 

“I’ve been in the drug discovery business for over 30 years now,” Robert Pacifici, Ph.D., the CHDI head scientist, told me in a 37-minute video interview after the conference, referring to the key theme of crucial modifier genes, a focus of the meeting. “I’ve never seen the mobilization of efforts as quickly and as deliberately – from the identification of those genes to the understanding of how those genes mechanistically are having their effect – to actually developing candidate therapies that are modifying those processes.”

 

Dr. Pacifici observed that, in the HD field, “everybody’s pushing wherever they can to accelerate therapeutics. But we all know that sometimes you just hit roadblocks, you hit bottlenecks.”

 

He said that those difficulties can be overcome with “new technologies, new methods, new techniques,” which often result in “breakthrough moments. They allow you to do things that you just could never contemplate doing before.”

 

Dr. Robert Pacifici, wearing a Team Hope shirt from the Huntington's Disease Society of America, overseeing the 20th Annual HD Therapeutics Conference (photo by Gene Veritas, aka Kenneth P. Serbin)

 

The efforts forming around this hottest of topics in the HD field are “incredibly exciting,” Dr. Pacifici said. The “big news” over the next two years should include getting drugs that imitate the effect of the modifier genes – which research has demonstrated delay the onset of HD symptoms – into clinical trial programs.

 

As reported in this blog, the now defunct Triplet Therapeutics had aimed from 2020-2022 to develop and test a modifier gene drug (click here to read more).

 

Dr. Pacifici said that he is “more optimistic” than ever that HD drugs will get approved.

 

I attended the conference. Below you can watch a video of my interview with Dr. Pacifici.

 

 

 

Attacking the harmful protein

 

While this year’s Therapeutics Conference did not include any major positive announcements like the approval of a drug, Dr. Pacifici observed that it also did not bring the kind of disappointing news experienced by the HD community in 2021 with negative results from trials run by Roche and Wave Life Sciences.

 

The conference did bring reports from both Roche and Wave about their revised clinical trial programs. PCT Therapeutics and uniQure also reported on their ongoing clinical trials.

 

All four programs use drugs to lower the amount of harmful mutant huntingtin protein in the brain cells of patients. This is the first of three approaches to defeating HD, Dr. Pacifici recalled.

 

I will detail these updates soon.

 

‘Lucky’ and ‘unlucky’ genes

 

The second, more recent approach involves the search for drugs to imitate the modifier genes, as Dr. Pacifici noted above. These genes are related to somatic instability – the tendency of the expanded HD gene to expand further with time. This process can be triggered by negative modifier genes.

 

Dr. Pacific described those genes as “lucky” or “unlucky.” A good modifier gene can delay HD onset, whereas the bad one can hasten the start of the disease, he explained.

 

These genes act as “sentinels” in the bookkeeping of our DNA, Dr. Pacifici added. “We want our DNA to stay clean and error-free.”

 

Dr. Pacifici emphasized how more than 12,000 HD-affected individuals and their relatives in genetic research helped lead to the discovery of the modifier genes a decade ago. A study of a large group of people’s DNA is known as a Genome Wide Association Study (GWAS).

 

Fixing broken cells

 

The third approach to treating HD involves yet another set of genes that emerged from the HD GWAS. They were a key topic at the conference.

 

Dr. Pacifici stated that these genes are “every bit as validated” as the ones involving somatic instability. “We just don’t know the effect yet,” he said.

 

Dr. Pacifici added that understanding these genes will help answer a key unanswered question about HD: “what is it actually inside a cell at the molecular level that’s broken” and how to fix it.

 

All three of these areas could be targeted by an eventual cocktail of HD drugs, Dr. Pacifici said.

 

Key new genetic research and ‘rock star’ HD families

 

“We keep on thinking of ways of getting even more information out of persons with HD,” Dr. Pacifici said.

 

CHDI has announced that all 22,000 participants in Enroll-HD, the global registry of HD patients and relatives, will be full-genome-sequenced. That means their entire DNA will be  mapped.

 

“That’s a lot of data,” Dr. Pacifici noted. “It’s going to be the next set of breakthroughs, where we understand not just little bits of DNA information but the whole story for every participant.”

 

This will be “incredibly impactful,” he said.

 

The HD families that have provided all of this crucial data underlying these approaches to treatments are true “rock stars,” Dr. Pacifici said. Their interaction with HD scientists is critical, he concluded, to advancing scientific breakthroughs.

Huntington’s disease community will 'get there' in search for therapies, CHDI chief scientist declares after ‘terrific’ conference

 

After presiding over a “terrific” research conference, CHDI Foundation Chief Scientific Officer Robert Pacifici, Ph.D., declared that the Huntington’s disease community will “get there” in the search for long-awaited therapies.

 

Dr. Pacifici commented in an interview with me on March 1, after the CHDI-sponsored 19th Annual HD Therapeutics Conference, held in Palm Springs, CA, from February 26-29.

 

The CHDI chief scientific officer (CSO) provided his optimistic assessment in referencing the featured presentation by David Altshuler, M.D., Ph.D., CSO of the Boston-based Vertex Pharmaceuticals.

 

“They’ve solved some unbelievably difficult problems,” Dr. Pacifici said of Vertex, noting that it found a cure for hepatitis C.

 

Vertex has also developed therapies for three tough diseases that, like HD, are genetic: cystic fibrosis, sickle cell disease, and transfusion-dependent beta thalassemia.

 

At future therapeutics conferences, “we would love for the last talk” to focus on a new drug that is “now going to be approved,’” Dr. Pacifici told me.

 

“We’re going to get there,” he continued. Dr. Altshuler, who Dr. Pacifici said carefully calibrates his optimism, “was very complimentary and very confident that if we stay on this path, we’ll actually achieve that. He felt that the collective efforts that CHDI is trying to catalyze throughout the community are going to be successful.”

 

Dr. Pacifici pointed out how CHDI has adhered to another key principle of drug discovery emphasized by Dr. Althsuler: studying HD in human cells, tissues, and postmortem samples.

 

Dr. Pacifici said he expects the HD field will hear more from Dr. Altshuler and welcomed Vertex’s possible revived involvement.

 

In 2010 I spoke on my family’s fight against HD at the Vertex labs in San Diego and chronicled its search at the time for an HD therapy, though so far without results reported by that lab.

 

Dr. David Altshuler presenting a timeline of Huntington's disease scientific landmarks at the 19th Annual Therapeutics Conference, February 28, 2024. Pictured in the slide is James Gusella, Ph.D., whose lab discovered the huntingtin genetic marker in 1983 and the gene in 1993 (photo by Gene Veritas, aka Kenneth P. Serbin, and posted with permission of CHDI Foundation). (Click on the image to make it larger.)

 

The need to celebrate milestones

 

“But I think what you will see is incremental successes,” Dr. Pacifici continued. “We’re going to have these new findings, these critical milestones and stepping stones along the way that we should embrace and celebrate and use those as a source of hope that, even though it never moves as fast as we would like, we’re making very real, tangible progress”

 

Dr. Pacifici described the 19th conference as “terrific,” noting that more than 450 people – a record – 50 companies, and 70 academic institutions took part. He recalled how no biopharma firms attended the first few conferences. Now such companies “come to a conference because they think an area is ripe for discovery,” he observed.

 

“Everybody commented on how quickly the conference went this year,” Dr. Pacifici said. “There was just so much information and so much happening and actually people were sad when it was over.”

 

I found this, my twelfth CHDI conference, particularly exhilarating because of the amount of new data and the high quality of the presentations.

 

A virtual nonprofit biotech, CHDI is the largest private funder of HD research. As in our interviews at past therapeutics conferences, Dr. Pacifici summarized the key findings of the scientists’ presentations. Watch our 39-minute interview in the video below.

 

 

Key developments

 

Dr. Pacifici explained several key developments.

 

The session on new data and insights into the basic biology of HD included presentations that help “to understand exactly how we can custom craft the profile of candidate drugs to make sure that they hit the right things and are as safe as possible,” Dr. Pacifici said. Such crafting would mean that drugs could effectively address the numerous specific problems in HD, he added.

 

Another session “shined a bright light” on DNA repair, modifier genes, and somatic instability, the tendency of the deleterious expansion of the DNA to worsen with age and therefore trigger disease onset, Dr. Pacifici said. The new findings can contribute to the ongoing effort to “manipulate” these processes to slow or stop instability and therefore prevent the disease, he explained.

 

Including talks detailing HD at the cellular and molecular level, the session titled “It’s a Brain Disease” was “unbelievably informative” about specifying how HD harms the brain, Dr. Pacifici said.

 

Clinical trial news and the importance of participation in research

 

The final session featured clinical trial updates from uniQure, PTC Therapeutics, and Roche. None of these has yet reached Phase 3, the definitive test of a drug.

 

Referring to the 2021 results of Roche’s first attempt at a Phase 3 trial, Dr. Pacifici noted that the firm’s scientists “have really gone to town and reanalyzed the samples, reanalyzed the data in a way that is hopefully going to teach us not only why that particular trial didn’t meet its endpoints” but also “what we can do differently.” Roche’s reassessment of its drug, tominersen, in a Phase 2 trial, GENERATION HD2, is in progress.

 

Ultimately, the field needs a “conveyor belt” of new drug possibilities to develop the multiple kinds of drugs necessary for treating different aspects of HD, Dr. Pacifici concluded. Not all those new drugs will be successful, he said, but the more produced, the greater likelihood for successful therapies.

 

Dr. Pacifici pointed out that many of the discoveries discussed at the meeting resulted from the human data collected from tens of thousands of research volunteers.

 

Future projects and breakthroughs will continue to rely on large numbers of participants, he said. Some individuals may carry unique genetic characteristics revealing new kinds of therapies.

 

“Hang in there,” Dr. Pacifici said in his closing comment for the HD community. “I hope that next year at the 20th [conference] we’ll have some more good news to communicate.”

 

Stay tuned for further news from the conference!

At CHDI conference, advocates inspire acceleration of quest for Huntington’s disease therapies

 

With a record 420-plus participants, the 19th Annual Huntington’s Disease Therapeutics Conference got under way on February 26 with the aim of speeding the quest for therapies to slow, halt, or reverse the symptoms of this incurable disorder.

 

Sponsored by CHDI Foundation, Inc., the largest private funder of HD research, the event runs through February 29 at the Parker hotel in Palm Springs, CA, and will feature three days of scientific and clinical presentations.

 

“In recent years the quest for HD therapeutics that will make a real difference to affected families has accelerated and deepened,” CHDI Chief Scientific Officer Robert Pacifici, Ph.D., wrote in a welcome letter to the participants. “Accelerated in the sense that every week seems to bring new scientific insight, whether from publications or reports on new and ongoing clinical initiatives. Deepened in the sense of the sophistication of our understanding of the underlying HD biology that informs our drug development work.”

 

HD research has also “broadened,” Dr. Pacifici added, noting that participants are displaying a record 140-plus posters. Representatives from 55 pharmaceutical and biotech companies and 69 academic institutions will take part.

 

In his letter and opening remarks to the conference, Dr. Pacifici outlined how CHDI has reorganized its scientific-thematic approach to “better align” its activities “with this burgeoning body of knowledge.”

 

The conference, following such themes, will focus on new research into the roles of mutant huntingtin DNA, RNA, and protein in HD. Conference-goers also will focus on the hot topic of somatic instability, the tendency of the deleterious expansion of the DNA to worsen with age and therefore trigger disease onset.

 

A caregiver’s moving keynote and a vital TED Talk

 

Following Dr. Pacifici’s overview, the audience watched a deeply moving 80-minute keynote speech, not to be shared publicly, by Cheryl Sullivan Stavely, RN. Stavely recounted her 30-plus years as an advocate and caregiver to her late husband John and daughter Meghan, who both succumbed to HD.

 

Stavely thanked the scientists for their dedication and said she hoped that 30 years from now HD conferences will become unnecessary with the development of treatments.

 

Choking up at Stavely’s recollections of Meghan, I found the keynote highly effective in summing up the many health and social challenges faced by HD-affected people and their families such as the affected person losing the ability to work and making insurance and end-of-life arrangements.

 

Scroll to the end of this article for photos of Stavely’s presentation and others.

 

Earlier, I interviewed leading HD global advocate, Emmy Award winning television journalist, and fellow HD gene expansion carrier Charles Sabine about his compelling TED Talk “The Unlimited Capability of Every Human.” Launched on February 1, the talk already has had 4,500 views.

 

Sabine stressed the importance of making the presentation “gather viral momentum” and transform the way HD is viewed by the general public everywhere. I will explore the implications of Sabine’s vital talk in a future article.

 

Stay tuned for further coverage of the therapeutics conference. 

 

Displaying a slide of daughter Meghan, Cheryl Sullivan Stavely delivers the keynote address at the 19th HD Therapeutics Conference, February 26, 2024 (this and the photos below by Gene Veritas, aka Kenneth P. Serbin).

The audience watching Stavely's presentation

Cheryl Sullivan Stavely and husband Kevin Stavely

 

Leslie Thompson, Ph.D., of the University of California, Irvine, greeting Kevin and Cheryl Stavely

 

Stavely with Karen Anderson, M.D., of Georgetown University

 

Stavely (left) with Haiying Tang, Ph.D., of CHDI and Wenzhen Duan, M.D., Ph.D., of Johns Hopkins University
 

After a difficult year for the Huntington’s disease cause, CHDI chief scientist feels ‘reinvigorated’ and ‘optimistic’ about quest for therapies

 

Having faced negative results in two key clinical trials a year ago while battling the coronavirus pandemic, the Huntington’s disease community has renewed the quest for therapies (treatments).

 

A vital sign of this: despite initial fears about the omicron variant of COVID-19, the 17th Annual HD Therapeutics Conference took place ­from February 28-March 3 at the Parker Palm Springs hotel in Palm Springs, CA. The 305 fully vaccinated attendees gathered under a massive tent, which allowed social distancing and provided good ventilation.

 

Shortly after the March 2020 conference, much of the world went on lockdown to avoid the ravages of the virus, pushing the 2021 conference online.

 

“I don't think it's hyperbole to say that coming here for this conference in person feels like a rebirth,” said Robert Pacifici, Ph.D., in a half-hour interview with me on March 4. “It's been a hard couple of years for everybody, but for the Huntington's disease community in particular.”

 

Dr. Pacifici is the chief scientific officer of the conference sponsor, CHDI Foundation, the nonprofit virtual biotech entity geared solely towards finding HD therapies. CHDI is the largest private funder of HD research.

 

In March 2021, the community “learned that two of the really well thought-out and very rational clinical trials for Huntington's disease had been halted and it dashed a lot of people's hopes,” recalled Dr. Pacifici, referring to GENERATION HD1, the largest clinical trial in HD history, run by Roche, and two smaller trials with a similar drug run by Wave Life Sciences.

 

Those results “must have been devastating” for people awaiting an “efficacious treatment,” Dr. Pacifici continued. “But we do what the Huntington's community always does: we persevere, we lift ourselves up by our bootstraps, and we go forward.”

 

Witnessing a “bunch of reasons” for hope about therapies at the conference, Dr. Pacifici declared, “I'm reinvigorated and very optimistic.”

 

For an overview of the conference and my interview with Dr. Pacifici, watch the video below.

 

 

Above, HD Therapeutics Conference attendees view scientific posters presenting new research, and, below, watch one of the many presentations at the four-day event (photos by Gene Veritas, aka Kenneth P. Serbin).

 

 

Learning from last year’s setbacks

 

At the Therapeutics Conference, Roche elaborated on new data from GENERATION HD1 and its plans to develop an improved clinical trial. Wave provided an update on its new early-stage trial, SELECT-HD.

 

Both firms use gene silencing drugs to attempt to reduce the amount of the toxic huntingtin protein in the brain (called huntingtin lowering). Both seek to build on the lessons learned from the 2021 setbacks.  (Click here to read about Roche’s recent announcement and here about Wave’s new trial.)

 

“I'm heartened that there's still a lot of enthusiasm for the huntingtin-lowering approach,” Dr. Pacifici observed. “There's actually a very impressive portfolio of other companies, therapeutic modalities, and approaches to huntingtin-lowering.”

 

Other plans to attack the mutant protein

 

PTC Therapeutics and Novartis Pharmaceuticals presented updates on their respective ongoing clinical trials using different huntingtin-lowering approaches. Whereas Roche and Wave drugs were administered via an uncomfortable spinal tap done at a clinic, PTC and Novartis use so-called small molecules: pills.

 

Besides the obvious convenience, such small-molecule drugs offer other key advantages, Dr. Pacifici explained.

 

“We know that mutant huntingtin is expressed everywhere [in the body] and so it’s good to know that you can lower it everywhere with a small molecule,” he said, noting that dosages can then be calibrated to achieve different lowering effects.

 

A higher dose creates more lowering, while a lower dose lessens it, Dr. Pacifici explained.

 

“From a safety perspective, if we ever found a long-term problem with huntingtin lowering, you can stop taking the compound and let the huntingtin come back so that then you can decide,” he continued, referring to a practice called picket-fence dosing, in which patients stop and restart dosing as needed.

 

Triplet gears up to test its approach

 

With no guarantee that reducing the toxic protein will result in an effective treatment, the Huntington’s field has purposefully diversified.

 

A key example is the work of Triplet Therapeutics. Triplet focuses on somatic expansion (also known as somatic instability), the tendency in HD of the already expanded (and therefore mutant) huntingtin gene to continue growing in length with age. The greater the expansion, the earlier the impact of the mutation on brain cells. This process is governed by recently discovered modifier genes that slow or hasten disease onset. (Click here and here to read more.)

 

“That's what actually causes the cells to malfunction, to die, and eventually leads to the underlying physiology of Huntington's,” Dr. Pacifici said. “So, not surprisingly, that gives us another therapeutic handle. Can we slow down that somatic instability?”

 

At the conference, two Triplet scientists presented a preliminary analysis of data from SHIELD-HD, a research study of 70 presymptomatic and early-disease-stage carriers of the HD mutation. SHIELD-HD is furnishing data for a clinical trial of Triplet's drug candidate, TTX-3360, aimed at blocking somatic expansion and, therefore, potentially delaying or avoiding HD onset.

 

Triplet Therapeutics scientists Irina Antonijevic, M.D., Ph.D., the chief medical officer (right), and Peter Bialek, Ph.D., senior director of translational science, after their presentation at the HD Therapeutics Conference (photo by Gene Veritas)

 

Founded in 2018, Triplet has used the science of somatic expansion and HD modifier genes to move with “record-breaking speed” towards a clinical trial, Dr. Pacifici said.

 

In a brief interview after the Triplet presentation, Irina Antonijevic, M.D., Ph.D., the company’s chief medical officer, confirmed that it will file a Clinical Trial Application this summer for permission to start a Phase 1 dose escalation clinical trial of TTX-3360, mainly to test safety and tolerability. Regulatory agencies can take a few months to review the application, after which the firm could start recruiting people with HD.

 

“We’re very excited,” Dr. Pacifici said. “The whole area of somatic instability is a great complement to huntingtin lowering. It's possible that eventually, if God forbid, huntingtin lowering turns out not to be viable, we've got a great backup plan. But even if it is, these things could actually synergize with each other. I could imagine people in the future being treated with a combination of therapies that address both of these things – lowering the huntingtin protein, but also preventing additional somatic instability.”

 

A future article will explore the SHIELD-HD presentation and Triplet’s clinical trial plans.

 

The value of family participation

 

Most of the conference presentations focused on human data, as opposed to research in animals. Dr. Pacifici pointed out that many advances in HD research result from the participation of thousands of gene carriers in studies and clinical trials.

 

“I appreciate that families are willing to give their time, their blood, their urine, and the travel, the poking, the prodding they're going through,” Dr. Pacifici said. “I want to express my heartfelt gratitude. This year, more than ever, I guess I'm happy to say I told you so, meaning that I always encourage people to participate and we're now seeing the fruits of that participation. We now have the evidence that those samples are being used judiciously and are providing unparalleled value.”

 

Dr. Pacifici also pointed to the steadfast commitment of both scientists and families to HD research during the pandemic, which “required people taking risk and going into the clinics and the labs.”

 

“Hang in there, be resilient, participate when you can,” Dr. Pacifici concluded, because a “really talented, committed global group of passionate drug discovery professionals would love nothing more than to deliver what you need so desperately, which are effective treatments for Huntington's disease.”

 

For my coverage of the start of the conference, click here.

 

For additional coverage, visit HDBuzz.

‘The first at-bat is never a grand slam’: how Huntington’s disease drug research has matured with the Roche and Wave setbacks

Despite the disappointing clinical trial results reported last week by Roche and Wave Life Sciences, Huntington’s disease drug researchers see an upside: they are using the data collected to achieve new insights, offering renewed hope of effective treatments.

 

The news of these setbacks produced one of the most heartbreaking moments of the last several decades for the HD community and researchers.

 

“That kind of news, I hope it’s okay to say: it sucks!” said Robert Pacifici, Ph.D., the chief scientific officer for CHDI Foundation, Inc., of the Roche and Wave trial data. “All of us who hold out so much hope and recognize that there are so many families who so desperately are waiting for much needed relief and therapies – it knocks the wind out of you.”

 

The companies made their first formal scientific presentations of their data at the start of the CHDI-sponsored 16th Annual HD Therapeutics Conference, held virtually from April 27-29. A nonprofit virtual biotech, CHDI focuses solely on developing Huntington’s therapies.

 

Roche confirmed that its drug tominersen failed to alleviate symptoms in its Phase 3 clinical trial; patients receiving the highest of two possible doses may have done even slightly worse than those on placebo. Two early-stage Wave trials failed to meet the goal of reducing the amount of mutant huntingtin protein in the trial participants – an objective already achieved by Roche in an earlier tominersen trial. (Click here to read more.)

 

Dr. Pacifici offered his assessment of the Roche and Wave data and the state of HD drug research in a wide-ranging, 46-minute Zoom interview with me after the close of the event.

 

Dr. Robert Pacifici moderates panel discussion of huntingtin-lowering clinical trial results with Dr. Vissia Viglietta of Wave Life Sciences and Dr. Scott Schobel of Roche (screenshot by Gene Veritas, aka Kenneth P. Serbin)

 

Gaining perspective

 

“My reaction though, now that I’ve come back down to earth, is really not one of surprise,” Dr. Pacifici said. “Drug discovery, as we’ve discussed many times, is a really tough business. The probability of success on any given endeavor is incredibly low.”

 

Dr. Pacifici used a baseball metaphor to explain: “How often does the first batter get up to the plate and hit a grand slam home run? A grand slam, never, because you need to load up the bases with three people. Even a home run is incredibly rare.”

 

The “name of the game” in discovering effective treatments is to carry out as many trials as necessary, “doing it well, failing, but making it a good failure that we can learn from so that subsequent efforts have a much higher chance of success,” Dr. Pacifici explained. “And we continue to snowball and build on that so that we can learn the things to do better, the things that we can do differently, or the things that we should stop doing altogether because we now have confirmed that those are not viable lines of investigation.”

 

The accumulation of experience through research and clinical trials, including the crucial participation of patient volunteers, has produced “an incredibly positive thing,” Dr. Pacifici observed.

 

“Look at how the field has matured,” he said. In the past, scientists would have kept a trial running for three years, waiting for patient improvement, only to discover that “the drug really didn’t even have a chance of working” because it hadn’t done what it was “tasked with doing, which is lowering huntingtin levels.”

 

Now the process is moving “faster” and is “better informed,” Dr. Pacifici said.

 

Watch the entirety of my interview with Dr. Pacifici in the video below.

 

Huntington's disease drug research now a 'mature field' from Gene Veritas on Vimeo.

 

Huntingtin lowering still in the running

 

Dr. Pacifici commented on the critical topic of lowering (reducing) the mutant huntingtin protein, the first strategy aimed at HD’s genetic cause. Scientists believe that the mutant protein is a main driver of the disease. In mouse studies, lowering that protein led to a disappearance of symptoms, and, beginning with the Roche trial, researchers have sought to achieve similar results in humans. Thus, until now, lowering mutant huntingtin has been seen as the potentially most promising path to a treatment.

 

Both Roche and Wave used a type of drug known as an antisense oligonucleotide (ASO), an artificial strand of DNA. Other firms and labs are also investigating ASOs.

 

“When two of those things don’t move forward simultaneously, it’s perfectly reasonable to ask the question, ‘Well, is this one of those times where we’ve learned that this approach is not going to work?’” Dr. Pacifici asked. “I can say unequivocally that that’s not yet the case. There are just too many things that factor into how a drug needs to do its job that remain unanswered.”

 

He said that possible key factors affecting the outcomes of the Roche and Wave trials include the stage of disease of the participants, the concentration of the drug tested, and the proper distribution of the drug within the brain. The particular characteristics of the drugs selected could have also impacted the outcome, he added.

 

Another possible explanation involves the design of the trials, the techniques for measuring patient response, and biomarkers (signs of disease and a drug’s effects).

 

In addition, even though Roche’s tominersen reduced the level of mutant huntingtin protein in trial volunteers’ cerebrospinal fluid, researchers still do not know whether the samples of protein actually came from the brain and, if so, cells relevant to HD, Dr. Pacifici cautioned. Scientists also lack other critical details about those samples; for example, they could be fragments, he said.

 

Crucially, the “interim analysis” of the Roche data at the Therapeutics conference did not demonstrate whether lowering huntingtin can help people feel, function, or survive better, Dr. Pacifici observed.

 

Even a “whisper of efficacy” would have validated the huntingtin-lowering approach and “prepared the path for subsequent trials with gusto and confidence,” he continued, adding, however, that “the opposite is not true. We still have great hopes that this is a viable mechanism of action.”

 

Wave plans to start a trial of a third ASO later this year. Roche has also stated that it will continue to explore drugs for HD.

 

Exploring other avenues

 

Because the effectiveness of huntingtin-lowering remains an open question for the field, Dr. Pacifici renewed his call to redouble and diversify drug-hunting efforts.

 

Dr. Pacifici noted that other potential huntingtin-lowering approaches are in the works using non-ASO compounds, while others propose different methods of delivery, including a pill. In the Roche and Wave trials, participants received the drug via spinal tap.

 

“If we were in a fantasy world of the 20th new treatment for Huntington’s coming, you would worry about things like convenience: ‘I’d like to have a pill instead of an injection,’” Dr. Pacifici said. “‘I’d like to have a pill I can take once a day. I’d like to have a small pill that’s easy to swallow.’”

 

However, Dr. Pacifici observed, “we’re not at that stage yet.” Even so, “very critical advantages” exist in exploring different modes of delivery, he said.

 

Indeed, another possibility emerged at the conference. A scientist from pharmaceutical giant Novartis presented research on its drug branaplam, a pill used to treat spinal muscular atrophy (SMA), which causes severe muscle weakness in children. Novartis researchers discovered that Branaplam also reduced the amount of the huntingtin protein in a study of SMA patients. Novartis plans a trial of branaplam in HD patients, with details expected in the coming weeks and over the summer (click here to read more).

 

Like other so-called small-molecule drugs, branaplam becomes distributed very evenly across the whole body, including the brain, whereas a drug like an ASO tends to concentrate where it is administered, Dr. Pacifici explained. He added that small-molecule drugs can be dosed “creatively” – for example, weekly instead of daily – to maximize the “beneficial effect” and allow the person a rest from the drug.

 

(I will explore the quest to develop this type of HD drug in a future article.)

 

Dr. Rajeev Sivasankaran of Novartis presents data demonstrating the effect of the drug branaplam on huntingtin RNA in a study of spinal muscular atrophy patients (screenshot by Gene Veritas).

 

Sharing knowledge rises all boats

 

Dr. Pacifici emphasized that success in the fight against HD ultimately depends on the sharing of scientific information – even negative research results that private companies are loathe to reveal to protect their egos and their stock prices.

 

He cited the presentation by featured speaker Aled Edwards, Ph.D., the founder and CEO of the Structural Genomix Consortium, which practices and advocates for open sharing of scientific information, particularly as it applies to protein science, chemical biology and drug discovery. Dr. Edwards spoke on “HD drug discovery in the public domain – a model for CHDI.”

 

“I think the HD field will benefit by everybody realizing how difficult this problem is,” Dr. Pacifici concluded. “It’s not giving up a competitive advantage by being transparent about what happened. It’s sharing data. That knowledge rises all boats. Everybody needs to know about these things.”

 

Sharing of data and other knowledge has also been one of CHDI’s trademarks as a nonprofit. Dr. Pacifici pointed to specifics: knowledge about the disease, potential treatments, biomarkers, and clinical outcome measures (the techniques for measuring patient response).

 

With such sharing, he asserted, everybody will have an increased chance of success.

 

Refusing to do so will “doom us to the same failure we see in other neurodegenerative fields that have outspent us and been at this a lot longer than we have.”