Northwestern and Agenus Initiate Phase 2a Trial of SonoCloud-9 Combination for Glioblastoma
25-Patient Trial to Evaluate Blood-Brain Barrier Disruption
The NCT05864534 trial, sponsored by Northwestern University and in collaboration with Agenus Inc. (AGEN) and Carthera SAS, is a Phase 2a study enrolling 25 patients with newly diagnosed, IDH wild-type, and MGMT unmethylated glioblastoma. The trial commenced on January 19, 2024, and is currently recruiting in Chicago, USA, with a primary completion date of July 31, 2031, and a last update on May 1, 2026. The design involves implanting SonoCloud-9, a device with nine ultrasound transducers, into the skull 1-5 weeks after the completion of standard radiation therapy to temporarily and reversibly open the blood-brain barrier (BBB). A key aspect of this platform trial is its focus on demonstrating safety, procedural feasibility, and the degree of BBB opening based on magnetic resonance imaging, rather than efficacy signals.
Simultaneous Enhancement of Intratumoral Exposure of Three Agents
Patients receive balstilimab and AGEN2034 (450mg) every three weeks, and botensilimab and AGEN1181 (1mg/kg) every six weeks, administered intravenously. Balstilimab is a PD-1 inhibitor, and botensilimab is a CTLA-4 antibody with enhanced Fc function, both targeting the immunosuppressive tumor microenvironment. In addition, Doxil (liposomal doxorubicin hydrochloride) is administered every three weeks; this anthracycline induces DNA intercalation and topoisomerase II inhibition. The strategy involves aligning SonoCloud-9 activation and drug administration in a 21-day cycle, repeated up to nine times, to increase BBB permeability. Enhanced safety monitoring is applied to the first six patients.
Addressing Delivery Limitations of Existing Standard of Care
The standard of care for newly diagnosed glioblastoma involves maximal safe surgical resection followed by radiation and concurrent and adjuvant temozolomide. Novocure Ltd. (NVCR)'s Optune Gio tumor treating fields (TTFields) may be added. The FDA approved Optune for recurrent glioblastoma in 2011 and for newly diagnosed patients in combination with temozolomide on October 5, 2015. In contrast, this trial aims to physically enhance the delivery of immune checkpoint inhibitors and cytotoxic chemotherapeutic agents to brain tumors, addressing the issue of temozolomide resistance in MGMT unmethylated patients. The competitive landscape includes Optune, as well as pembrolizumab-based immunotherapy and clinical pipelines combining implantable ultrasound with carboplatin or paclitaxel.
Regulatory Value and Commercialization Gateway
SonoCloud-9 received FDA Breakthrough Device designation on June 22, 2022, but NCT05864534 is registered as an unapproved/investigational device. Doxil was first approved in the United States on November 17, 1995, but its use in glioblastoma is not within the approved indications, and its use in this trial is for research purposes. Balstilimab and botensilimab are also clinical-stage candidates without commercial brands or FDA, EMA, or PMDA marketing approvals, and there is no history of FDA Advisory Committee (AdComm) votes on this combination. The global glioblastoma drug market was valued at USD 0.79 billion in 2025, but given the 25-patient, single-center trial, the key inflection points for investment decisions are the reproducibility of BBB opening, the occurrence of severe immune toxicities, survival outcomes, and the initiation of subsequent confirmatory trials.
This study is a 25-patient Phase 2a trial evaluating the clinical value of a blood-brain barrier delivery platform, rather than the drug itself, in the USD 0.79 billion global glioblastoma drug market in 2025. In the short term, the ability of Agenus Inc. (AGEN)'s PD-1/CTLA-4 combination and Carthera SAS's SonoCloud-9 to demonstrate safety, BBB opening reproducibility, and early survival signals will be a catalyst for corporate value. For researchers, it provides human clinical evidence that immune-oncology agents and Doxil can increase intratumoral exposure in newly diagnosed, MGMT unmethylated patients. The competitive landscape includes surgery, radiation, Temodar, and FDA-approved Optune Gio, with pembrolizumab combinations and other focused ultrasound pipelines targeting the same patient population. In the medium to long term, commercialization will require safety data prior to the planned primary completion in 2031, multi-center confirmatory trials, FDA medical device approval, and separate regulatory validation of the unapproved drug combination.
Source: ClinicalTrials.gov (api_ct)