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November 22, 2022


A Letter From Mark de Souza, PhD, SonALAsense CEO, to the DIPG/DMG Community

In the last six weeks, we have shared exciting milestones with you the DIPG and DMG communities. The first child in SDT-201, our Phase 1/2 trial in DIPG, received SDT using SONALA-001 and ultrasound. The moment gave me pause to consider what this means for all the stakeholders, our team at SonALAsense, the clinicians across the country, the FDA, and most importantly, what it means for you the patients, caretakers, and bereaved families who are waiting eagerly for a non-invasive effective treatment for DMG, including DIPG, to treat your loved one.

I am a father of two children I love very much. I’m also the uncle to a teen with neurofibromatosis type 1 which leads to tumors arising from nerve cells. While I can’t truly know the very difficult road as a parent of a DIPG or DMG patient, I can empathize with you and imagine what I would want to do to protect my child and give my child the best chance for healing and quality of life.

In fact, I carry forth that perspective in all I do. My role as a father and also an uncle to a rare disease warrior is a big influence in every decision I must make. It is a part of the urgency our team feels to move our Phase 1/2 safety trial forward quickly. It is the reason for the investment in strong compassionate patient navigation. It is part of the proactive planning of resources we do to make sure our clinical trials will not stall due to a lack of funding or trial sites.

As a father first, I know choosing a safe trial design matters. I’m committed to working hard to bring that to the community. As a parent I would be searching for any option. It is for that reason I want to communicate with you in a way many CEOs may not. I want to take the opportunity to tell you where we are in our rollout of SDT. I want to explain what we are doing at SonALAsense to develop SDT and evaluate its safety and efficacy in the shortest time frame possible to support FDA and other regulatory approvals. As much as we wish it were yesterday, it takes time to perform the clinical trials necessary to demonstrate safety and efficacy with our dedicated clinical trial investigators. I am eager to reach the day I can tell you these trials prove our therapy is effective to combat DIPG, DMG and GBM. When I do, I want you to see the research data from a well-designed clinical trial backing it up.

For now, I can share what we know. We have just started with SDT using ALA and ultrasound in the pons.  We do not know what doses of drug and ultrasound energy are well tolerated safely. We also do not know what effect it will have on the tumor or whether it will provide clinical benefit. We focus all our resources, both financial resources and human resources on moving to a safe dose that is also effective as soon as we can. Unfortunately, for this same reason, it is too early for SonALAsense to offer a compassionate use or expanded access program today. When we have more information on how to treat children with DIPG. Including the right dose and data that show benefit, then we will be ready to discuss these options with the FDA and the community to help as many children as much as we can.

We do however have ongoing clinical trials. You will find these at this link


Very rarely, our investigators seek permission from us and the FDA to treat a patient who is not eligible for our clinical trials but may provide very important information to the overall trial research. When they do, this process is called Single Patient Expanded Access. It is with this a second child with DIPG was treated to learn more about the method on someone who did not recently receive radiation and had a different tumor presentation than a typical trial patient.

There are many limitations to treating patients outside of our protocol. Pushing these limits early may pose a risk to our dose escalation schedule and ability to bring SDT to the DIPG and GBM community as therapy quickly. To work around these limitations, one of our investigators has proposed a trial to evaluate the safety and efficacy of SDT in patients with DIPG who are not eligible for our SDT-201 clinical trial. Setting this up will take several months because we will need to find the funding for this trial and file the paperwork to get the trial protocol approved by ethics committees and the FDA.

Time is not a word I use lightly as I know time is not often on your side. I share your feelings and pain and use them to balance my responsibilities for safe and effective drug development. Our innovative, talented team of doctors, researchers, and staff with decades of experience in clinical operations, regulatory affairs, manufacturing, and other functional areas have spent our careers developing drugs for rare diseases. Most of these diseases have no approved therapies. This is a sweet spot for our team. We have advanced multiple drugs and drug-device combinations through FDA approval into mainline treatment because we believe those with rare diseases deserve options for quality of life and long life.

Please allow our team a chance to work through these hurdles to bring SDT to  a broader group of patients than those eligible for SDT-201 once we have sufficient safety data and have determined the optimal dose of the drug and ultrasound energy.  Please trust that our team and I are as excited about the potential of SDT as I know you are. Please know that we are moving as quickly as we can to bring SDT to those affected by DIPG and GBM.  Please feel that YOU are driving us forward because we know YOU deserve better treatments and more options.  Please understand we will do all we can to provide that to you in as short a timeframe as possible. Finally, please continue to advocate for your loved ones and the other children and adults with DIPG, DMG, and GBM. We can move the needle together, as fast as possible, to the day these tumor types no longer claim lives and devastate families. We hear you. We won’t stop listening. We’re working hard to change the course.


Mark de Souza, PhD

Chief Executive Officer


Dad to Isabella and Kian

Uncle to Prithvi

From the Desk of the CEO

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