EndolucinBeta (Lutetium-177 Chloride)
Radiopharmaceutical precursor for targeted radionuclide therapy in nuclear medicine
Quick Facts about EndolucinBeta
Key Takeaways about EndolucinBeta
- Radiopharmaceutical precursor: EndolucinBeta is not given directly to patients but is used to radiolabel carrier molecules in hospital radiopharmacies under strict quality control
- Targeted cancer therapy: When attached to tumour-targeting peptides, lutetium-177 delivers precise beta radiation to cancer cells while minimising damage to surrounding healthy tissue
- Primary application in NETs: The most established use is in peptide receptor radionuclide therapy (PRRT) for somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumours
- Hospital-only product: Handled exclusively in authorised nuclear medicine departments by trained specialists and radiopharmacists with appropriate radiation protection measures
- EMA-approved since 2016: EndolucinBeta received European marketing authorisation from the European Medicines Agency, confirming its quality, safety, and efficacy as a radiolabeling precursor
What Is EndolucinBeta and What Is It Used For?
EndolucinBeta is a radiopharmaceutical precursor containing lutetium-177 chloride (¹⁷⁷Lu-Cl₃). It is used in nuclear medicine to radiolabel carrier molecules – peptides, antibodies, or other biomolecules – to create therapeutic radiopharmaceuticals that deliver targeted radiation therapy to tumour cells. Its principal clinical application is in peptide receptor radionuclide therapy (PRRT) for gastroenteropancreatic neuroendocrine tumours.
EndolucinBeta belongs to a category of products known as radiopharmaceutical precursors. Unlike conventional medicines that are administered directly to patients, EndolucinBeta serves as a building block: it provides the radioactive component (lutetium-177) that is chemically attached to a carrier molecule in a process called radiolabeling. The resulting radiolabeled product is then what the patient actually receives. This approach allows nuclear medicine departments to prepare customised radiopharmaceuticals on-site, tailored to the specific clinical needs of individual patients.
Lutetium-177 (¹⁷⁷Lu) is a lanthanide radionuclide that decays predominantly by beta-minus emission, releasing electrons with a maximum energy of 498 keV (average 134 keV) and a maximum soft tissue penetration of approximately 2 millimetres. This relatively short range is therapeutically advantageous because it concentrates radiation damage within the tumour while limiting exposure to surrounding healthy tissue. Additionally, lutetium-177 emits low-energy gamma photons (208 keV at 11% abundance and 113 keV at 6.4% abundance), which can be detected by gamma cameras and single-photon emission computed tomography (SPECT) scanners. This dual emission profile – therapeutic beta particles and diagnostic gamma photons – makes lutetium-177 a true “theranostic” radionuclide, enabling simultaneous treatment and imaging.
The physical half-life of lutetium-177 is 6.647 days, which is considered optimal for targeted radionuclide therapy. It is long enough to allow for production, transportation, radiolabeling, quality control, and patient administration, yet short enough to deliver the therapeutic radiation dose efficiently and then decay to negligible levels within a few weeks. The daughter nuclide, hafnium-177, is stable and non-radioactive.
The primary clinical applications of EndolucinBeta, once radiolabeled with appropriate carrier molecules, include:
- Peptide receptor radionuclide therapy (PRRT): When lutetium-177 is attached to somatostatin analogues such as DOTATATE or DOTATOC, the resulting radiopharmaceutical binds to somatostatin receptors that are overexpressed on neuroendocrine tumour cells. This is the most established and widely used application, supported by the landmark NETTER-1 phase III clinical trial.
- Radioligand therapy for prostate cancer: Lutetium-177 can be attached to prostate-specific membrane antigen (PSMA) ligands to target metastatic castration-resistant prostate cancer (mCRPC). This application has gained significant momentum following the positive results of the VISION trial.
- Radioimmunotherapy: By attaching lutetium-177 to monoclonal antibodies or antibody fragments, targeted radiation can be delivered to various tumour types expressing specific surface antigens. This approach is under active investigation in clinical trials for lymphoma, breast cancer, and other malignancies.
- Bone pain palliation: Lutetium-177-labelled bisphosphonates and other bone-seeking agents are being investigated for the treatment of painful bone metastases from various primary cancers.
- Research and emerging applications: Numerous clinical trials are exploring lutetium-177-based therapies in additional tumour types, including meningioma, glioblastoma, and various solid tumours with targetable surface receptors.
EndolucinBeta received its initial European marketing authorisation from the European Medicines Agency (EMA) in 2016 under the trade name EndolucinBeta, manufactured by ITM Isotopen Technologien München AG. It was one of the first lutetium-177 chloride products to receive formal regulatory approval in Europe, reflecting the growing recognition of targeted radionuclide therapy as a validated treatment modality in oncology.
EndolucinBeta is produced using two principal methods: reactor irradiation of enriched ytterbium-176 targets (indirect or carrier-added production) and direct neutron irradiation of enriched lutetium-176 targets (direct or no-carrier-added production). The production method affects the specific activity of the final product, which in turn influences the efficiency of radiolabeling. No-carrier-added lutetium-177 generally offers higher specific activity, which is preferable for many clinical applications as it allows more radioactivity to be attached to each carrier molecule.
The product is supplied as a sterile, clear, colourless solution of lutetium-177 chloride in dilute hydrochloric acid, intended for use in the radiolabeling of carrier molecules that have been specifically developed and validated for use with lutetium-177. The radiolabeling process, quality control testing, and subsequent patient administration are all performed within authorised nuclear medicine facilities by trained personnel following strict radiation protection protocols and good radiopharmacy practice (GRPh) guidelines.
What Should You Know Before Receiving EndolucinBeta-Based Therapy?
Before receiving lutetium-177-based therapy, your doctor will perform comprehensive assessments including blood tests, kidney function evaluation, imaging studies, and a thorough review of your medical history. Patients with severe kidney impairment, severely suppressed bone marrow function, or who are pregnant must not receive this therapy.
Because EndolucinBeta is a radiopharmaceutical precursor that is used to prepare the final therapeutic product administered to patients, the safety considerations apply primarily to the radiolabeled compound that results from the radiolabeling process. The following information pertains to lutetium-177-based therapies in general, with particular reference to PRRT for neuroendocrine tumours, as this is the most established clinical application.
Your nuclear medicine specialist will conduct a thorough pre-treatment evaluation to determine whether lutetium-177-based therapy is appropriate for your specific situation. This assessment is critical for ensuring both the safety and efficacy of treatment. The decision to proceed involves careful consideration of multiple factors, and the treatment team typically includes nuclear medicine physicians, oncologists, radiopharmacists, and radiation safety officers working together.
Contraindications
Lutetium-177-based therapy must not be given in the following circumstances:
- Hypersensitivity: Known allergy to lutetium-177 chloride, to the carrier molecule (e.g. DOTATATE), or to any of the excipients in the final radiolabeled preparation. Allergic reactions to radiopharmaceuticals are rare but can occur.
- Pregnancy: Ionising radiation poses a significant risk to the developing foetus, including the potential for congenital malformations, growth restriction, and childhood cancer. A negative pregnancy test is required before each treatment cycle for women of childbearing potential.
- Breastfeeding: Radioactive materials are excreted in breast milk. Breastfeeding must be discontinued before treatment and must not be resumed after treatment with lutetium-177, as the radioactive half-life means significant radioactivity would be present in breast milk for an extended period.
- Severe renal impairment: The kidneys are a dose-limiting organ for lutetium-177-based therapy. Patients with severely compromised kidney function (GFR below 30 ml/min) are generally excluded from treatment due to the risk of further renal damage and altered pharmacokinetics.
- Severe haematological compromise: Bone marrow suppression is a significant side effect of lutetium-177 therapy. Patients with pre-existing severe cytopenias (very low blood cell counts) may not tolerate additional myelosuppression.
Warnings and Precautions
Talk to your nuclear medicine specialist before receiving lutetium-177-based therapy if any of the following apply to you:
- Moderate renal impairment: While not an absolute contraindication, reduced kidney function requires careful dose planning and potentially dose reduction. Amino acid co-infusion (typically containing L-lysine and L-arginine) is administered before and during each PRRT session to protect the kidneys by competitively inhibiting renal tubular reabsorption of the radiolabeled peptide.
- Prior chemotherapy or radiotherapy: Previous cancer treatments that affect bone marrow reserve may increase the risk of haematological toxicity. Your doctor will review your treatment history and may adjust the lutetium-177 activity accordingly.
- Liver metastases: Extensive hepatic tumour burden may affect the pharmacokinetics of the radiolabeled product and increase the risk of hepatotoxicity. However, liver metastases are common in neuroendocrine tumour patients, and treatment can still be beneficial when carefully managed.
- Bone metastases: Widespread bone involvement may increase the risk of myelosuppression due to radiation exposure of the bone marrow. Dosimetry-guided treatment planning can help optimise the therapeutic window.
- Cardiac conditions: Some patients may experience cardiac symptoms related to hormonal release from tumours during treatment (carcinoid crisis). Pre-medication with octreotide and careful monitoring are standard precautions.
Pregnancy and Fertility
EndolucinBeta-based therapies involve ionising radiation, which is harmful to the developing foetus at any stage of pregnancy. Women of childbearing potential must use effective contraception during treatment and for at least 6 months after the last treatment cycle. Men undergoing treatment should use effective contraception for at least 6 months following their last treatment session, as radiation may temporarily or permanently affect sperm production.
Lutetium-177 therapy may affect fertility in both men and women. In men, the radiation dose to the testes from circulating radioactivity can cause temporary or, in some cases, permanent oligospermia or azoospermia. Sperm banking should be discussed before starting treatment. In women, the radiation dose to the ovaries may lead to premature ovarian insufficiency, particularly in women closer to natural menopause. Fertility preservation options should be discussed with all patients of reproductive age before initiating treatment.
If you discover that you are pregnant during or shortly after treatment, inform your nuclear medicine team immediately. Radiation dose estimation to the foetus may be performed, and appropriate counselling will be provided regarding potential risks.
Radiation Safety Precautions After Treatment
After receiving lutetium-177-based therapy, you will be radioactive for a period of time. Your nuclear medicine team will provide detailed instructions regarding radiation protection measures, which typically include:
- Limiting close contact (within 1 metre) with other people, especially pregnant women and young children, for a specified period (typically 3–7 days)
- Sleeping in a separate bed for a specified period
- Maintaining good hygiene practices, including flushing the toilet twice after use and washing hands thoroughly
- Avoiding public transport for the first 24–48 hours after treatment where possible
- Carrying a treatment card that explains your radioactive status in case of emergency medical attention or security screening
EndolucinBeta is a radioactive product that must only be handled by authorised personnel in appropriately licensed nuclear medicine facilities. It must never be handled outside of a controlled radiation environment. Patients receiving lutetium-177-based therapies must follow all radiation protection instructions provided by their treatment team to minimise unnecessary radiation exposure to family members, caregivers, and the general public.
How Does EndolucinBeta-Based Therapy Interact with Other Drugs?
Lutetium-177-based therapy can interact with several types of medications. The most clinically significant interactions involve somatostatin analogues (which may compete for receptor binding), nephrotoxic drugs (which increase kidney risk), and myelosuppressive agents (which worsen blood count suppression). All current medications should be reviewed by the nuclear medicine team before treatment.
Drug interactions with lutetium-177-based therapies are primarily related to the carrier molecule and the target organ systems rather than to lutetium-177 chloride itself. Because the radiolabeled product targets specific biological receptors or pathways, any medication that affects those same pathways can potentially influence treatment efficacy or toxicity. The following interactions are most relevant for PRRT with lutetium-177-DOTATATE, which is the most common clinical application.
Your nuclear medicine specialist and oncologist will review all your current medications, including over-the-counter drugs and supplements, before each treatment cycle. The following table summarises the most important known drug interactions:
| Interacting Drug | Effect | Clinical Significance | Recommendation |
|---|---|---|---|
| Long-acting somatostatin analogues (e.g. octreotide LAR, lanreotide) | Compete for somatostatin receptor binding, potentially reducing tumour uptake of radiolabeled peptide | Major | Discontinue long-acting formulations 4–6 weeks before PRRT; short-acting octreotide may be used for symptom control up to 24 hours before treatment |
| Nephrotoxic drugs (e.g. aminoglycosides, NSAIDs, cisplatin, contrast agents) | Additive nephrotoxicity risk; kidneys are dose-limiting organs in PRRT | Major | Avoid concomitant use where possible; ensure adequate hydration; monitor renal function closely |
| Myelosuppressive chemotherapy (e.g. capecitabine, temozolomide, everolimus) | Additive bone marrow suppression, increasing risk of severe cytopenias | Major | Combination requires careful timing and dose adjustment; concurrent capecitabine may be used under trial protocols with enhanced monitoring |
| Corticosteroids (e.g. dexamethasone, prednisolone) | May affect somatostatin receptor expression on tumour cells; can mask signs of infection during myelosuppression | Moderate | Use the minimum effective dose; monitor for infection during the myelosuppressive period |
| Targeted therapies (e.g. sunitinib, everolimus) | Potential overlap in toxicity profiles (myelosuppression, mucositis); everolimus may alter somatostatin receptor expression | Moderate | Washout period recommended before starting PRRT; sequential rather than concurrent use preferred |
| ACE inhibitors and ARBs | May alter renal perfusion and tubular function, potentially affecting kidney radiation dose | Minor | Generally safe to continue; monitor renal function; inform treatment team |
Important Considerations for Drug Interactions
The amino acid co-infusion used during PRRT to protect the kidneys (typically containing L-lysine and L-arginine) can itself cause nausea and vomiting, which may be exacerbated by other emetogenic medications. Anti-emetic prophylaxis with ondansetron or similar agents is routinely administered before the amino acid infusion.
For patients receiving lutetium-177-PSMA therapy for prostate cancer, androgen deprivation therapy (ADT) is typically continued throughout treatment, as it may enhance PSMA expression on tumour cells and potentially improve treatment efficacy. However, specific interactions between ADT agents and the radioligand are still being characterised in ongoing clinical studies.
Herbal supplements and complementary medicines should be disclosed to the treatment team, as some products (such as those containing antioxidants in high doses) may theoretically reduce the effectiveness of radiation-based therapy by scavenging free radicals that contribute to the mechanism of cell killing. While the clinical significance of this interaction is not fully established, caution is generally recommended.
What Is the Correct Dosage of EndolucinBeta-Based Therapy?
The activity (dose) of lutetium-177 administered to patients varies depending on the specific radiolabeled product and clinical indication. For PRRT with lutetium-177-DOTATATE in neuroendocrine tumours, the standard regimen is 7.4 GBq (200 mCi) per cycle, administered intravenously every 8 weeks for a total of 4 cycles. Dosing is always determined by the nuclear medicine specialist based on individual patient factors.
It is important to understand that EndolucinBeta itself does not have a “patient dose” in the conventional sense. The activity of lutetium-177 used in the radiolabeling process is determined by the nuclear medicine team based on the intended patient dose, the efficiency of the radiolabeling procedure, and quality control requirements. The following dosing information refers to the final radiolabeled products administered to patients.
PRRT for Neuroendocrine Tumours (Lu-177-DOTATATE)
| Parameter | Standard Protocol | Modified Protocol | Notes |
|---|---|---|---|
| Activity per cycle | 7.4 GBq (200 mCi) | 3.7–5.55 GBq (100–150 mCi) | Reduced dose for renal impairment or haematological compromise |
| Number of cycles | 4 cycles | 2–8 cycles | Based on response, tolerability, and cumulative organ doses |
| Interval between cycles | 8 weeks (±1 week) | 8–16 weeks | Extended interval if blood counts have not recovered sufficiently |
| Maximum cumulative activity | 29.6 GBq (800 mCi) | Individualised | Based on dosimetry; kidney and bone marrow dose limits |
| Infusion duration | ~30 minutes | 20–40 minutes | Slow intravenous infusion with gravity or infusion pump |
| Amino acid co-infusion | Required (L-lysine/L-arginine) | Required | Started 30 min before PRRT; continued for 4 hours; renal protection |
The standard PRRT protocol established by the NETTER-1 trial consists of four intravenous administrations of 7.4 GBq (200 mCi) lutetium-177-DOTATATE at approximately 8-week intervals. This regimen delivered a cumulative activity of 29.6 GBq (800 mCi) and demonstrated a statistically significant improvement in progression-free survival compared to high-dose octreotide alone in patients with advanced midgut neuroendocrine tumours.
Before each treatment cycle, the nuclear medicine team verifies that the patient meets specific haematological and renal criteria. These typically include an absolute neutrophil count above 1.5 × 10⁹/L, a platelet count above 80 × 10⁹/L, haemoglobin above 80 g/L, and creatinine clearance above 40 ml/min. If these criteria are not met, treatment may be delayed until recovery occurs, or the administered activity may be reduced.
Radioligand Therapy for Prostate Cancer (Lu-177-PSMA)
For lutetium-177-PSMA therapy in metastatic castration-resistant prostate cancer, the dosing protocol typically involves 6 cycles of 7.4 GBq (200 mCi) administered at 6-week intervals, as established by the VISION trial. As with PRRT, individual dose modifications may be necessary based on the patient’s haematological status, renal function, and clinical response.
Special Populations
No specific dose adjustment based solely on age is generally recommended for lutetium-177-based therapies. However, elderly patients often have reduced bone marrow reserve and declining renal function, which may necessitate more conservative dosing and closer monitoring. The decision to treat elderly patients should consider overall performance status, life expectancy, and the expected benefit-risk ratio.
For patients with moderate renal impairment (GFR 30–60 ml/min), dose reduction and enhanced renal dosimetry are recommended. The amino acid co-infusion for kidney protection is particularly critical in these patients. Activity reduction by 25–50% may be considered, and the interval between cycles may be extended to allow for adequate renal recovery.
Delayed or Missed Treatment Cycle
If a scheduled treatment cycle is delayed due to insufficient blood count recovery or other medical reasons, the cycle is simply postponed until the criteria are met. There is no concept of a “missed dose” in the traditional sense, as each cycle is administered only when the patient is medically fit. If the interval between cycles extends beyond 16 weeks, the treatment team will reassess the overall treatment plan and may recommend reimaging to evaluate disease status before continuing.
Overdose Considerations
An overdose of radioactivity carries the risk of excessive radiation exposure to critical organs, particularly the bone marrow and kidneys. In the event of accidental overexposure, management is primarily supportive: increasing oral hydration to promote renal excretion, monitoring blood counts frequently for evidence of severe myelosuppression, and providing haematopoietic growth factors (G-CSF) if necessary. There is no specific antidote for lutetium-177 exposure, but the physical half-life of 6.647 days means that radioactivity will naturally decline over time.
Advances in treatment planning increasingly favour personalised dosimetry, where the radiation dose to individual organs (particularly kidneys and bone marrow) is calculated for each patient using post-treatment SPECT/CT imaging. This approach allows treatment to be optimised on a per-patient basis, potentially enabling higher cumulative activities in patients with favourable organ dosimetry while protecting those at higher risk of toxicity.
What Are the Side Effects of EndolucinBeta-Based Therapy?
The most common side effects of lutetium-177-based therapy include nausea and vomiting (often related to the amino acid co-infusion), bone marrow suppression (leading to reduced blood cell counts), fatigue, and temporary hair thinning. Serious but less common effects include renal toxicity and secondary haematological malignancies. Your treatment team will monitor blood counts and kidney function closely throughout the treatment course.
The side effects described below relate to lutetium-177-based therapies administered to patients, not to EndolucinBeta as a precursor product. The safety profile is well characterised from clinical trials (NETTER-1, VISION) and extensive post-marketing experience. Side effects are primarily related to radiation exposure of normal tissues, particularly the bone marrow and kidneys, which are the dose-limiting organs for this class of therapy.
Most side effects are manageable and reversible with appropriate supportive care. However, long-term monitoring is essential because some adverse effects (such as secondary haematological malignancies) may not become apparent until months or years after treatment completion.
Signs of severe bone marrow suppression, including unexplained fever or infection (neutropenic fever), unusual bruising or bleeding, or severe fatigue with pallor. These symptoms may indicate dangerously low blood cell counts that require urgent medical intervention including hospitalisation, intravenous antibiotics, blood transfusions, or growth factor support.
Very Common Side Effects
- Nausea (often related to amino acid co-infusion; manageable with anti-emetics)
- Vomiting (particularly during and after treatment sessions)
- Fatigue and general malaise (may persist for 1–2 weeks after each cycle)
- Lymphopenia (reduced lymphocyte count)
- Thrombocytopenia (reduced platelet count; nadir typically at 4–6 weeks)
- Anaemia (reduced red blood cell count; may be cumulative over treatment cycles)
- Leucopenia (reduced white blood cell count)
Common Side Effects
- Temporary hair thinning (alopecia; usually mild and reversible)
- Decreased appetite and weight loss
- Abdominal pain or discomfort
- Diarrhoea or constipation
- Mild renal function impairment (usually subclinical)
- Elevated liver enzymes (transient)
- Neutropenia (reduced neutrophil count)
- Dizziness
- Headache
Uncommon Side Effects
- Pancytopenia (reduction of all blood cell types)
- Febrile neutropenia (fever with low white blood cells; medical emergency)
- Significant renal impairment requiring dose modification
- Hormonal crisis (carcinoid crisis in NET patients; managed with octreotide)
- Secondary myelodysplastic syndrome (MDS)
- Dry mouth (xerostomia; due to radiation exposure of salivary glands)
Rare Side Effects
- Acute myeloid leukaemia (AML; secondary to radiation exposure; typically occurs >2 years post-treatment)
- Severe or irreversible renal failure
- Severe hepatotoxicity (in patients with extensive liver metastases)
- Allergic reaction to the radiolabeled product or excipients
Haematological Monitoring
Blood count monitoring is the cornerstone of safety assessment during lutetium-177-based therapy. Complete blood counts should be performed at baseline, at 2–3 weeks after each cycle (to detect early cytopenias), and at 6–8 weeks after each cycle (to assess nadir and recovery). The lymphocyte count is typically the most affected parameter, with lymphopenia being nearly universal. Thrombocytopenia usually reaches its nadir at 4–6 weeks post-treatment and recovers by 8 weeks. Anaemia may be cumulative over successive treatment cycles.
The risk of haematological toxicity is increased in patients with extensive bone metastases (due to radiation of the bone marrow), prior myelosuppressive chemotherapy, and impaired renal function (which prolongs the circulation time of the radiolabeled product). Persistent grade 3–4 cytopenias beyond 8 weeks should prompt investigation for underlying causes including myelodysplastic syndrome.
Long-Term Monitoring
Given the potential for late-onset side effects, patients who have received lutetium-177-based therapy should undergo long-term follow-up including annual complete blood counts and renal function assessment for at least 5 years after completing treatment. The cumulative incidence of therapy-related myelodysplastic syndrome or acute myeloid leukaemia is estimated at 1–3% based on available long-term data, and patients should be counselled about this risk before starting treatment.
How Should EndolucinBeta Be Stored?
EndolucinBeta must be stored in a licensed radioactive materials storage facility within an authorised nuclear medicine department. It requires lead-shielded containers, specific temperature conditions, and must never be handled outside controlled radiation environments. Patients do not store this product at home.
Unlike conventional oral medications, EndolucinBeta is never dispensed to patients for home use. It is a radioactive product that remains within the nuclear medicine department at all times until it is used for radiolabeling and the resulting product is administered to the patient under medical supervision. The storage requirements reflect both pharmaceutical quality standards and radiation safety regulations.
The specific storage conditions for EndolucinBeta include:
- Temperature: Store below 25°C. Do not freeze. Protect from excessive heat.
- Shielding: Store in the original lead-shielded container (pig) provided by the manufacturer. Additional lead shielding may be required depending on the activity level.
- Secure storage: Store in a locked radioactive materials storage room with restricted access, as required by national radiation protection regulations.
- Labelling: All containers must be clearly labelled with the radionuclide identity, activity, reference date and time, and appropriate radiation warning symbols.
- Shelf life: The usable life is limited by radioactive decay. The product must be used within the shelf life specified by the manufacturer (typically 7–14 days from the reference date, depending on the initial activity).
- Disposal: Unused product and all materials that have come into contact with EndolucinBeta must be disposed of as radioactive waste in accordance with national regulations. This typically involves decay-in-storage until radioactivity falls below clearance levels.
The storage area must be equipped with radiation monitoring instruments, contamination detection equipment, and spill containment materials. Regular contamination surveys must be performed, and personnel working in the storage area must wear personal dosimeters and follow ALARA (As Low As Reasonably Achievable) principles to minimise their radiation exposure.
What Does EndolucinBeta Contain?
EndolucinBeta contains lutetium-177 chloride as the active substance in a sterile solution of dilute hydrochloric acid. The product is a clear, colourless solution that is GMP-manufactured and tested for radiochemical purity, radionuclidic purity, and sterility before release.
EndolucinBeta is a highly purified radiopharmaceutical product with a simple composition designed to ensure compatibility with a wide range of radiolabeling procedures. The formulation is intentionally minimalistic to avoid introducing substances that could interfere with the chemistry of the radiolabeling process.
Active Substance
The active substance is lutetium-177 chloride (¹⁷⁷LuCl₃), a radioactive compound of the lanthanide element lutetium. Lutetium-177 is produced by neutron irradiation in a nuclear reactor, either from enriched ytterbium-176 targets (indirect production route, yielding no-carrier-added lutetium-177) or from enriched lutetium-176 targets (direct production route, yielding carrier-added lutetium-177). The specific activity of the product depends on the production method and is specified on the product label.
Excipients
The excipients (inactive ingredients) are limited to:
- Hydrochloric acid (HCl): Present in dilute concentration (approximately 0.04 M) to maintain the lutetium-177 in solution and prevent hydrolysis. This acidic environment ensures chemical stability and compatibility with standard radiolabeling procedures.
- Water for injections: Pharmaceutical-grade water meeting the requirements of the European Pharmacopoeia, used as the solvent.
Quality Specifications
Each batch of EndolucinBeta undergoes rigorous quality control testing before release, including:
- Radionuclidic purity: Verification that the product contains lutetium-177 without significant contamination by other radionuclides (such as lutetium-177m, which has a much longer half-life)
- Radiochemical purity: Confirmation that the lutetium-177 is present in the correct chemical form (chloride)
- Specific activity: Measurement of the radioactivity per unit mass of lutetium, which determines the efficiency of subsequent radiolabeling
- pH: Verified to be within the specified range
- Sterility: The product must be sterile, as it is used in the preparation of products for intravenous administration
- Bacterial endotoxin testing: Ensures the product is free from pyrogens
- Metal impurities: Verified to be below specified limits, as metal contaminants can interfere with radiolabeling efficiency
The product appearance is a clear, colourless solution. Any visible particles, cloudiness, or discolouration would indicate a quality defect, and such vials must not be used. The radiopharmacist performs a visual inspection before using EndolucinBeta for any radiolabeling procedure.
Frequently Asked Questions about EndolucinBeta
EndolucinBeta is a radiopharmaceutical precursor containing lutetium-177 chloride. It is used in nuclear medicine to radiolabel (attach radioactivity to) carrier molecules such as peptides and antibodies, creating therapeutic radiopharmaceuticals. The most common application is preparing lutetium-177-DOTATATE for peptide receptor radionuclide therapy (PRRT) in patients with somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumours. It is also used for lutetium-177-PSMA therapy in prostate cancer and in various research applications.
Lutetium-177 is a beta-emitting radionuclide that delivers targeted radiation to tumour cells. When attached to carrier molecules that bind to specific receptors overexpressed on tumour cells (such as somatostatin receptors on neuroendocrine tumours or PSMA on prostate cancer cells), it delivers focused beta radiation with a range of approximately 2 mm. This radiation damages the DNA of cancer cells, leading to cell death. The short range of the beta particles means that damage is concentrated within the tumour, minimising harm to surrounding healthy tissue. Additionally, the gamma emissions from lutetium-177 allow doctors to image the distribution of the therapy using SPECT/CT scanners.
EndolucinBeta is handled exclusively in authorised nuclear medicine departments within hospitals or specialised treatment centres. The radiolabeling process, quality control, and subsequent patient administration are performed by trained nuclear medicine specialists and radiopharmacists under strict radiation protection protocols. Patients cannot receive this treatment at home or in a general clinic. Depending on local regulations and the specific protocol, patients may be treated as inpatients (overnight stay for radiation monitoring) or as outpatients (discharged on the same day with radiation safety instructions).
The most common side effects include nausea and vomiting (often related to the kidney-protective amino acid infusion given alongside treatment), bone marrow suppression leading to reduced blood cell counts (anaemia, low white cells, low platelets), fatigue, and temporary hair thinning. Less common but more serious effects include significant kidney impairment and a small long-term risk (1–3%) of secondary blood cancers such as myelodysplastic syndrome or acute myeloid leukaemia. Blood counts and kidney function are closely monitored before and after each treatment cycle.
For PRRT in neuroendocrine tumours, the standard protocol involves 4 treatment cycles administered at intervals of approximately 8 weeks. For lutetium-177-PSMA therapy in prostate cancer, up to 6 cycles at 6-week intervals may be given. The exact number of cycles may be adjusted based on the patient’s blood counts, kidney function, clinical response, and tolerability. Some patients may receive fewer cycles if significant side effects develop, while others with favourable dosimetry may be considered for additional cycles beyond the standard regimen.
No, they are different products. EndolucinBeta is a radiopharmaceutical precursor containing lutetium-177 chloride – essentially the “raw radioactive ingredient” used in hospital radiopharmacies. Lutathera (lutetium Lu 177 dotatate) is a finished radiopharmaceutical product where lutetium-177 is already chemically attached to the peptide DOTATATE, ready for patient administration. EndolucinBeta can be used to prepare radiolabeled compounds including DOTATATE preparations in hospital radiopharmacies, offering flexibility for different clinical applications and carrier molecules beyond what is available as a pre-made product.
References
All medical information in this article is based on peer-reviewed research, international clinical guidelines, and authoritative pharmaceutical references. The following sources were used:
- European Medicines Agency (EMA). EndolucinBeta – Summary of Product Characteristics. EMA; 2024.
- Strosberg J, El-Haddad G, Wolin E, et al. Phase 3 Trial of 177Lu-Dotatate for Midgut Neuroendocrine Tumors. N Engl J Med. 2017;376(2):125-135. doi:10.1056/NEJMoa1607427 (NETTER-1 Trial)
- Sartor O, de Bono J, Chi KN, et al. Lutetium-177-PSMA-617 for Metastatic Castration-Resistant Prostate Cancer. N Engl J Med. 2021;385(12):1091-1103. doi:10.1056/NEJMoa2107322 (VISION Trial)
- European Association of Nuclear Medicine (EANM). Joint IAEA, EANM, and SNMMI Practical Guidance on Peptide Receptor Radionuclide Therapy (PRRNT) in Neuroendocrine Tumours. Eur J Nucl Med Mol Imaging. 2023;50(5):1201-1234.
- Bodei L, Mueller-Brand J, Baum RP, et al. The joint IAEA, EANM, and SNMMI practical guidance on peptide receptor radionuclide therapy (PRRNT) in neuroendocrine tumours. Eur J Nucl Med Mol Imaging. 2013;40(5):800-816. doi:10.1007/s00259-012-2330-6
- International Atomic Energy Agency (IAEA). Radiation Safety and Monitoring of Nuclear Medicine Patients. Safety Report Series No. 117. Vienna: IAEA; 2023.
- Kwekkeboom DJ, de Herder WW, Kam BL, et al. Treatment with the radiolabeled somatostatin analog [177Lu-DOTA0,Tyr3]octreotate: toxicity, efficacy, and survival. J Clin Oncol. 2008;26(13):2124-2130. doi:10.1200/JCO.2007.15.2553
- Brabander T, van der Zwan WA, Teunissen JJM, et al. Long-Term Efficacy, Survival, and Safety of [177Lu-DOTA0,Tyr3]octreotate in Patients with Gastroenteropancreatic and Bronchial Neuroendocrine Tumors. Clin Cancer Res. 2017;23(16):4617-4624. doi:10.1158/1078-0432.CCR-16-2743
- National Comprehensive Cancer Network (NCCN). Clinical Practice Guidelines in Oncology: Neuroendocrine and Adrenal Tumors. Version 2.2025.
- European Neuroendocrine Tumor Society (ENETS). ENETS Consensus Guidelines for the Management of Patients with Digestive Neuroendocrine Neoplasms. Neuroendocrinology. 2023;113:1-35.
Editorial Team
This article was written and medically reviewed by the iMedic Medical Editorial Team, comprising licensed physicians specialising in nuclear medicine, oncology, and radiation safety.
iMedic Medical Editorial Team
Specialists in Nuclear Medicine
iMedic Medical Review Board
Independent medical expert panel
Level 1A Evidence
GRADE Framework Applied
WHO, EMA, EANM, IAEA
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