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Prostates and PARPs
LONDON & BOSTON—Theragnostics has announced a handful of big things in the last few months, starting with a commercial partnership with GE Healthcare for a prostate cancer imaging agent and a license agreement with AstraZeneca for the development of an rPARPi therapeutic. The company also reported positive clinical trial results from its novel prostate cancer diagnostic imaging study.
Beginning with the recent partnership between GE Healthcare and Theragnostics, the companies have plans for a new prostate-specific membrane antigen (PSMA) PET/CT imaging agent. Theragnostics will lead the development of the tracer, GalliProst, while GE Healthcare will lead all pre-approval commercial preparations and all subsequent commercial and distribution activities.
“We are excited to partner with Theragnostics on GalliProst to give vital insights into prostate cancer,” said Sanka Thiru, global product leader for molecular imaging oncology in GE Healthcare’s Pharmaceutical Diagnostics business. “We believe that this partnership enables both parties to leverage each other’s key areas of expertise in order to accelerate the development of GalliProst and ultimately improve patient care.”
The diagnostic workflow for detecting prostate cancer starts with a blood test or biopsy, and patients are then typically referred for PET/CT imaging so that radiologists can see their tumor, lymph nodes and any metastasis in order to decide on an appropriate course of treatment. The “heat map” style image enabled by the new tracer shows the precise location and intensity of PSMA, which is expressed on the surface of prostate cancer cells.
“This agreement is validation of the potential for our novel prostate cancer Gallium-68 (68Ga) diagnostic tracer, GalliProst, which can benefit the treatment of prostate cancer patients around the globe. We are very pleased to sign our second agreement with GE Healthcare, following our agreement last year for a diagnostic tracer for imaging kidney function and scarring,” added Greg Mullen, CEO of Theragnostics.
Theragnostics also shared data from its Phase 2 clinical study, as well as its successful completion. The PRONOUNCED trial is a prospective open-label study of 50 patients to evaluate the safety and clinical impact of Gallium-68 (68Ga) THP-PSMA PET/CT imaging (THP-PSMA) on patient management and treatment decisions in men who are newly diagnosed, or who have biochemically recurrent prostate cancer after initial treatment.
“The PRONOUNCED study was completed with a substantial number of changes to the treatment regime made following the THP-PSMA scan and shows how this exciting technology can influence the management of prostate cancer patients,” stated Prof. Jamshed Bomanji, co-investigator and head of department at the Institute of Nuclear Medicine of the University College London Hospitals NHS Foundation Trust. “The new THP-PSMA PET/CT imaging allows for prospective analysis of the clinical disease status rather than retrospective, allowing for better-informed decision-making.”
The data demonstrate that post-THP-PSMA scan, one-third of newly diagnosed prostate cancer patients and over 50 percent of patients with biochemically recurrent disease—including 75 percent in a post-radical radiotherapy setting—saw their treatment plan altered to be more appropriate as a result of re-staging their prostate cancer with the GalliProst scan. The safety data showed that THP-PSMA was well tolerated with no serious adverse events reported, and was therefore considered safe.
“We are very pleased that the PRONOUNCED trial has completed with such a positive result; this combined with a positive meeting with the FDA earlier this year on our route to NDA submission are key milestones in bringing THP-PSMA to patients,” Mullen said. “We are convinced that a THP-PSMA scan will benefit the treatment of prostate cancer patients by better-informed and faster decision-making. We look forward to sharing these data with the medical community at upcoming scientific congresses and in peer-reviewed publications.”
In September, Theragnostics also announced a license agreement with AstraZeneca for intellectual property that enables Theragnostics to operate globally in the diagnostic field of certain selected radionuclide-labelled PARPi (poly [ADP-ribose] polymerase inhibitors). The agreement includes an option to an exclusive license for freedom to operate globally in the therapeutic field of certain selected radionuclide-labelled PARPi.
PARP inhibitors block an enzyme that cancer cells use in response to DNA damage, both endogenous and as caused by treatments like chemotherapy. The potential market for PARP inhibitors is large. There are at least four approved conventional pharmaceutical PARPi on the market, with new and expanded indications being approved in several markets in recent months, opening up a multibillion-dollar opportunity. PARPi is a therapeutic class that could be applicable in up to 40 percent of tumors, with varying DNA damage response-associated mutations or dependencies, and may have additional efficacy in combination with chemotherapy or radiotherapy.
Theragnostics’ technology platform enables the development of molecular radiotherapy based on a PARPi for imaging and treating cancer. Theragnostics modifies a PARPi drug molecule with a radioactive atom to create a radionuclide PARPi (rPARPi). This can either be used to image PARP in a cancer patient for diagnostic use, or to deliver a therapeutic dose of radiation into tumor cells, which offers the potential to molecularly target the radiation in order to hit and kill tumor cells while avoiding damage to healthy cells and associated side effects.
“We believe that a radionuclide PARPi therapy will work independently of DNA mutations associated with heightened PARPi activity, such as BRCA1/BRCA2, and will avoid development of treatment resistance,” explained Gareth Smith, chief operating officer of Theragnostics. “Therefore, the number of patients benefiting from PARPi therapy could significantly expand.”
This agreement follows Theragnostics’ global licensing agreement for rPARPi with Memorial Sloan Kettering Cancer Center in February 2019. Together, these agreements give Theragnostics flexibility and expanded capabilities to design and develop a broad range of both diagnostic and therapeutic molecular radiotherapies.
“This agreement with AstraZeneca strengthens our IP estate and enables us to accelerate the development of our rPARPi therapy and diagnostic portfolio, which has the potential to offer new and expanded treatment options to patients in a number of cancers,” Mullen noted.