In a nutshell
This study investigated the effectiveness of a radionuclide (RN), [¹??Lu]-PSMA-617, to treat metastatic castration-resistant prostate cancer (mCRPC) that has worsened after standard treatments. They found that this treatment was safe and effective for these patients.
Prostate cancer (PC) affects the prostate gland. The prognosis for PC is good if it is treated at an early stage. If cancer spreads it is called metastatic. This is more difficult to treat. One option is a procedure to cut off the supply of testosterone. This is called castration. Unfortunately, this does not work for all patients. This type of PC is called metastatic castration-resistant PC (mCRPC).
New treatments for mCRPC are needed. Using compounds that are more selective could be useful. These could target tumors more efficiently. Radionuclides (RN) are small molecules that can attach to proteins. They emit a radiation signal that kills the tumor cell. Lutetium-177 [¹??Lu]-PSMA-617 is a RN that targets prostate-specific membrane antigen (PSMA). PSMA is a protein found in high levels on the surface of prostate cancer. Targeting PSMA tumor cells may be an effective treatment for mCRPC.
Methods & findings
This study included 30 men with mCRPC. Patients were assessed for PSMA levels. All patients underwent radiation treatment with [¹??Lu]-PSMA-617. There were up to 4 treatment sessions. This involved an intravenous infusion every 6 weeks. Patients were assessed up to 3 months after the treatment ended. PSMA levels were measured. Scans were also performed to assess the response to treatment.
29 out of 30 patients (97%) had PSMA reductions to some degree. 57% of patients had a significant reduction in PSMA levels (of 50% or more). A more than 50% reduction in PSMA was associated with higher survival rates.
No treatment-related deaths were observed during the study. Side effects were generally mild. They included dry mouth (1 patient), nausea and fatigue (15 patients). Low platelet count was reported in 4 patients. Pain severity scores improved at all timepoints.
The bottom line
The authors concluded that the radionuclide treatment with [¹??Lu]-PSMA-617 was effective and safe in patients with mCRPC who have worsened after standard treatments.
The fine print
This trial included a relatively small number of patients. In addition, only patients with a specific PSMA level were included in the trial. Although it is encouraging, further studies are needed to determine the effectiveness of this treatment.
Published By :
The Lancet. Oncology
May 07, 2018
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