Cancer treatment is well-known to be a gruelling process. Chemotherapy causes a range of unpleasant side effects including hair loss, exhaustion and a weakened immune system. Radiotherapy can lead to lymphedema, fatigue and numerous problems with eating and drinking. Side effects of immunotherapy affect fewer patients than other treatments, but the technology is still in early stages and can’t be used to treat the majority of patients.
Now, University of Michigan spin-out HistoSonics has developed a novel cancer treatment using ultrasound technology to target malignant cells. The company’s robotics platform, Edison, employs robotically assisted sonic therapy (RAST) to destroy and liquefy targeted tissues at sub-cellular levels. It’s able to do this while preserving the surrounding, non-targeted tissue, where other methods of cancer treatment can see this damaged as well.
HistoSonics vice-president of marketing Josh King says: “Edison delivers a non-invasive, non-thermal and non-ionizing method to precisely destroy diseased or unwanted tissues.”
Forming a bubble cloud
The therapeutic technique in use here is called histotripsy. Pulsed soundwaves are used to create a ‘bubble cloud’ that destroys tissue while simultaneously allowing for real-time visualisation by clinicians to enable precise tissue destruction. The bubble cloud is a space where negative pressure is so strong that it pulls native gas out of a target point within tissue. The cloud forms and collapses thousands of times a second to pull apart cells and destroy them.
A patient simply lies on a table and Edison’s ultrasound transducer is positioned over the site of their tumour. Just like in an ultrasound of a foetus, the clinician is able to see the tumour in real time.
King says: “Once a targeted treatment plan has been created by a physician, the platform can deliver a series of ultrasound sensing pulses to discrete points inside the targeted tissue. These sensing pulses create a personalised treatment plan for each patient and the software ensures the treatment is delivered to all aspects of the target. This precision method of destroying tumours is guided through the 3D volume of the tumour by the on-board software and remains under the continuous visualization of the treating physician.
“Once the procedure begins, the treating physician monitors both the treatment and the treatment effect on the targeted tissue in real time. The physician is in total control throughout the procedure.”
Stepping on a foot pedal then commences the treatment. The bubble cloud created pulses up and down through a pre-planned volume to destroy the tumour, always being visualised by the physician delivering it. Where other methods of tumour treatment may leave clinicians unsure which tissues they’ve managed to eradicate, histotripsy makes this a lot clearer.
King says: “We believe there are many applications where histotripsy may provide clinical, quality of life and economic benefits.”
The results of the first in-human clinical trial of HistoSonics’ technology were announced at the 2019 Society of Interventional Oncology Annual Meeting. The study saw Edison successfully destroy 11 tumours in eight patients, each of whom had one, two or three tumours targeted and treated in a single session. They all had multifocal liver malignancy as well as metastasis from other organs, including breast and colorectal cancers.
All 11 of the RAST procedures carried out were able to destroy the planned targeted volume of tissue, and no patients reported pain or requested pain relief post-procedure. All treated areas healed rapidly following the procedure, and treatment volumes contracted by an average of 81% upon two-month follow-up imaging.
To the liver and beyond
HistoSonics was originally developed to treat benign prostate hyperplasia, a non-cancerous swelling of the prostate gland, but under the leadership of current CEO Mike Blue the company shifted to a wider focus in 2017. Edison’s focus is now to eventually treat multiple diseases in multiple organs.
Alongside the human trial into liver tumours, the company has done preclinical work in animal kidneys, spleens, and has completed proof of concept testing in animal thyroid and brain models. Alongside the results of the human trial, HistoSonics was able to use the same conference to announce that RAST showed promise in treating melanoma, liver and thyroid tumours in rodent models.
The company also suspects to discover other applications in certain vascular diseases and neurologic conditions.
In April 2019, it closed a $54m Series C funding round, led by Varian Medical Systems and including contributions from Johnson & Johnson and the State of Wisconsin Investment Board. It is currently busy establishing a new headquarters in Minneapolis and will soon move to seek regulatory approval in Europe and the US.
“HistoSonics believes that the precision, non-invasive, non-ionizing treatment platform being developed can be valuable to both physicians and patients in a growing market,” says King.