Johnson & Johnson is acquiring Halda Therapeutics for $3.05 billion, aiming to expand its prostate cancer portfolio and secure access to Halda’s innovative cell-death technology. The deal also reinforces J&J’s franchise built around its existing prostate cancer therapy, Erleada.
Halda’s Novel RIPTAC Platform
At the core of this acquisition lies Halda’s regulated induced proximity targeting chimera (RIPTAC) platform. This technology generates bifunctional small molecules that bind both a tumor-specific protein and a protein essential for cell survival. By doing so, the platform directly induces cancer cell death.
Moreover, Halda believes this “hold and kill” mechanism could overcome cancer’s tendency to develop resistance through bypass pathways. As per Fierce Biotech, researchers view this approach as a potentially significant advance in targeted oncology.
Early Clinical Promise for Lead Candidate HLD-0915
The timing of Monday’s announcement closely follows Halda’s release of early phase 1 data for HLD-0915, the platform’s lead asset and a key driver of J&J’s interest. HLD-0915 targets both the androgen receptor and bromodomain 4 (BRD4), two proteins linked to prostate cancer progression.
In an ongoing phase 1/2 study, Halda enrolled 31 patients with metastatic castration-resistant prostate cancer (mCRPC). All participants had progressed on previous therapies, including at least one androgen receptor pathway inhibitor such as Erleada. Many patients had also undergone up to two taxane chemotherapy regimens and, in some cases, radioligand therapy like Novartis’ Pluvicto.
Encouraging PSA Reductions
Among the 22 patients who completed at least two cycles of the once-daily oral treatment at various dose levels, 59% achieved more than a 50% reduction in prostate-specific antigen (PSA). Additionally, 32% achieved reductions exceeding 90%. These results were presented at last month’s AACR-NCI-EORTC molecular targets meeting.
Safety Profile and Dose Selection
Halda reported that treatment-related adverse events were generally infrequent and low grade. However, one patient at the highest tested dose (100 mg) developed dose-limiting liver enzyme and bilirubin elevations. Importantly, all grade 3 or higher TRAEs were reversible, and investigators reported no treatment-related deaths.
Based on these findings, Halda selected the 25-mg and 50-mg doses for expansion testing. These cohorts will help determine the optimal dose for future registrational trials.