Tarlatamab + Radiation for Cancer

(RABBIT Trial)

Overseen By Rachel E Jarrett, MPH

Age: 18+

Sex: Any

Trial Phase: Phase 1 & 2

Sponsor: University of Arizona

Must not be taking: Immunosuppressants, Steroids

Disqualifiers: Interstitial lung disease, Pneumonitis, Autoimmune, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

Duration: Up to 24 months

30 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new drug, tarlatamab, combined with radiation therapy, to determine its safety in treating certain cancers. The focus is on cancers that have recurred after treatment, such as specific lung cancers and other tumors with particular features. If the combination proves safe, the trial will explore its use for both body and brain tumors. Should radiation pose too much risk, the study will evaluate tarlatamab alone. Individuals with cancers that have returned after treatment and can undergo radiation may be suitable candidates for this trial. As a Phase 1 trial, this research aims to understand how the treatment works in people, offering participants the opportunity to be among the first to receive this new drug.

Will I have to stop taking my current medications?

The trial protocol does not specify if you need to stop taking your current medications. However, there is a 'washout period' (time without taking certain medications) of 7 days before and after radiation therapy during the first two cycles of treatment. It's best to discuss your specific medications with the trial team.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that tarlatamab has been tested in patients with small cell lung cancer (SCLC) and has produced promising results in shrinking tumors. In these studies, patients received a 10-mg dose every two weeks. While the treatment had lasting effects, some patients experienced side effects, including cytokine release syndrome (CRS) and immune-effector cell-associated neurotoxicity syndrome (ICANS), particularly during the first treatment cycle.

When combined with radiation therapy, studies reported a high tumor shrinkage rate of 83.3%. However, safety information for using tarlatamab with radiation therapy is still being gathered. The trial aims to explore safety further by starting with areas outside the brain before considering brain areas, ensuring any potential risks are well understood before expanding.

Overall, while early research indicates that tarlatamab can be effective, there are known side effects. The trial is designed to carefully monitor these and assess how well patients tolerate the treatment with radiation therapy. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about tarlatamab because it offers a novel approach to targeting cancer cells. Unlike standard treatments like chemotherapy and radiation that attack both cancerous and healthy cells, tarlatamab specifically targets cancer cells by engaging the body's immune system. It works through a mechanism called bispecific T-cell engagement, which directs the immune system's T-cells to attack tumor cells more precisely. This targeted action not only promises to be more effective but also potentially reduces side effects associated with less specific cancer treatments.

What evidence suggests that this trial's treatments could be effective for cancer?

Research has shown that tarlatamab, a type of immunotherapy, holds promise for treating certain cancers. In one study, 42.9% of patients with small cell lung cancer responded to tarlatamab. Another study found that it helped patients live longer and slowed cancer growth more effectively than chemotherapy. In this trial, participants may receive tarlatamab alone or with radiation therapy. When combined with radiation, tarlatamab did not significantly increase severe side effects, suggesting it can be safely used with this treatment. Overall, these findings suggest tarlatamab may be an effective cancer treatment, especially when combined with radiation. ^{6 7 8 9 10}

Who Is on the Research Team?

Charles Hsu, MD

Principal Investigator

University of Arizona

Ricklie Julian, MD

Principal Investigator

University of Arizona

Are You a Good Fit for This Trial?

This trial is for patients with various cancers, including lung, skin, and bladder cancer. Participants must have tumors expressing DLL3 and be suitable for radiation therapy. Specific eligibility criteria are not provided but typically include factors like age, health status, and prior treatments.

Inclusion Criteria

Subject has provided informed consent/assent prior to initiation of any study specific activities/procedures

Minimum life expectancy of 12 weeks

I can have radiation therapy on a cancer spot that hasn't been treated with radiation before.

Exclusion Criteria

I have not received any vaccines during the study period.

I don't have allergies to the study drugs and can attend all study visits.

I am not planning to conceive, and will follow the study's birth control requirements.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive tarlatamab with concurrent radiation therapy to extracranial sites, with dose escalation and monitoring for safety

Up to 24 months

Every 2 weeks (in-person)

Sequential Radiation Therapy

If concurrent therapy is not safe, participants receive sequential tarlatamab and radiation therapy with a 7-day washout period

Up to 24 months

Follow-up

Participants are monitored for safety and effectiveness after treatment

6 months

What Are the Treatments Tested in This Trial?

Interventions

• Concurrent Radiation Therapy
• Sequential Radiation therapy
• Tarlatamab

Trial Overview The study tests Tarlatamab combined with standard radiation therapy (RT), either given at the same time or sequentially. It starts with extracranial sites and may expand to cranial sites if safe. The goal is to assess safety first then efficacy, especially in non-small cell lung cancer types.

How Is the Trial Designed?

Group I: Tarlatamab Monotherapy Cohort Experimental Treatment 1 Intervention

If the sequential safety endpoint is not met, then the study will proceed to another de-escalation phase, where 10 patients will receive tarlatamab alone.

Group II: Sequential radiation therapy cohort Experimental Treatment 2 Interventions

If the concurrent main cohort safety endpoint is not met, then the study will proceed to de-escalation, where 20 patients will be enrolled on the sequential radiation therapy cohort. In this cohort patients will receive sequential tarlatamab and RT to cranial and extracranial RT sites. Standard of care RT can occur prior to Cycle 1 Day 1(if radiation treatment is completed \<7 days prior to the start of tarlatamab) or be interdigitated with tarlatamab with a 7-day washout between RT and infusion, with RT to begin as early as Cycle 1 Day 22 and as late as cycle 2 Day 28, assuming no ongoing CRS/ICANS.

Group III: Concurrent Main Cohort Experimental Treatment 2 Interventions

Patients enrolled to this cohort will receive tarlatamab with concurrent radiation therapy (RT) to extracranial sites (n=20-24 extracranial RT with a minimum of 10 thoracic patients). Patients will receive tarlatamab at a step-up dose of 1 mg on Cycle 1 Day 1 and then 10 mg on cycle 1 Day 8 and Cycle 1 Day 15 and every 2 weeks thereafter (on days 1 and 15 of each cycle) until radiographic progression or disease progression or 24 months, whichever is earlier. Patients will receive concurrent RT to extracranial sites as per standard of care starting as early as Cycle 1 Day 16 and as late as Cycle 2 Day 28, assuming there is no ongoing cytokine release syndrome (CRS) or immune-effector cell-associated neurotoxicity Syndrome (ICANS).

Group IV: Concurrent Cranial Cohort Experimental Treatment 2 Interventions

If the safety endpoint in the Concurrent Main Cohort is met, enrollment will expand to the Concurrent Cranial Cohort. 6-10 patients will receive tarlatamab with concurrent radiation therapy to cranial sites as described in the Concurrent Main Cohort.

Who Is Running the Clinical Trial?

University of Arizona

Lead Sponsor

Trials

545

Recruited

161,000+

Amgen

Industry Sponsor

Trials

1,508

Recruited

1,433,000+

Founded

1980

Headquarters

Thousand Oaks, USA

Known For

Human Therapeutics

Top Products

Enbrel, Prolia, Neulasta, Otezla

Robert A. Bradway

Amgen

Chief Executive Officer since 2012

MBA from Harvard Business School

Paul Burton

Amgen

Chief Medical Officer since 2023

MD from University of London, PhD in Molecular and Cellular Biology from Imperial College London

Published Research Related to This Trial

Combining radiotherapy with immune treatment shows strong potential for enhancing the immune response against cancer, as radiation can increase the expression of key molecules that help the immune system recognize and attack tumors.

Preliminary clinical studies suggest that this combination therapy can effectively control local tumors and even lead to regression of distant metastases without significantly increasing side effects compared to using each treatment alone.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Combination of radiotherapy and immune treatment: First clinical data. De Ruysscher, D.[2018]

In a study of 60 patients receiving combined immunotherapy and thoracic radiation therapy (iRT), no patients experienced severe grade ≥4 toxicities, indicating a favorable safety profile for this treatment approach.

While some patients did experience grade 3 toxicities, particularly pulmonary and hematologic issues, the overall short-term safety of iRT suggests it can be administered without significant risk of severe adverse effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of Combined Immunotherapy and Thoracic Radiation Therapy: Analysis of 3 Single-Institutional Phase I/II Trials. Verma, V., Cushman, TR., Selek, U., et al.[2022]

Combining radiation therapy with immunotherapy shows great potential for enhancing cancer treatment, as preclinical studies suggest that radiation can make tumor cells more vulnerable to immune attacks.

Clinical trials have begun to support the idea that this combination can effectively boost antitumor immune responses, with ongoing studies exploring various therapeutic vaccines alongside radiation therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Combining radiation and immunotherapy for synergistic antitumor therapy. Ferrara, TA., Hodge, JW., Gulley, JL.[2021]

In a study of 44,498 patients with stage IV non-small-cell lung cancer (NSCLC), stereotactic radiotherapy (SRT) was associated with improved overall survival (OS), showing a hazard ratio of 0.78, indicating a significant benefit regardless of the type of systemic treatment used.

The combination of SRT and immunotherapy showed promising results, with patients receiving SRT having a median OS of 18.2 months compared to 14.3 months for those on chemotherapy, suggesting that SRT may enhance the effectiveness of immunotherapy and warrants further investigation in randomized trials.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Overall survival according to immunotherapy and radiation treatment for metastatic non-small-cell lung cancer: a National Cancer Database analysis. Foster, CC., Sher, DJ., Rusthoven, CG., et al.[2020]

A 74-year-old woman with lung adenocarcinoma developed fatal immune thrombocytopenia after receiving pembrolizumab following radiotherapy, highlighting a potential risk of severe immune-related adverse events (irAEs) when combining these treatments.

Flow cytometry analysis showed increased PD-1 and Ki-67 expression in T cells post-radiotherapy, suggesting that radiotherapy may enhance immune activation and contribute to the development of irAEs in patients undergoing anti-PD-1 therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pembrolizumab-related Immune Thrombocytopenia in a Patient with Lung Adenocarcinoma Treated by Radiotherapy: Potential Immune-related Adverse Event Elicited by Radiation Therapy. Tamanoi, D., Saruwatari, K., Imamura, K., et al.[2022]

Stereotactic ablative body radiotherapy (SABR) not only delivers high doses of radiation to tumors but also has significant immunomodulatory effects that can enhance the body's anti-tumor immune response.

Combining SABR with immune checkpoint inhibitors can improve treatment outcomes by overcoming tumor-induced immunosuppression and preparing tumors for a stronger adaptive immune response, as shown in early phase clinical studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The optimism surrounding stereotactic body radiation therapy and immunomodulation. Tharmalingam, H., Hoskin, PJ.[2018]

In a study of 133 patients with metastatic cancers receiving immune checkpoint inhibitors and radiation, 34.6% experienced immune-related adverse events (ir-AEs), with higher rates observed in those receiving both CTLA-4 and PD-1 inhibitors (71% vs 29%).

The combination of palliative radiation and immune checkpoint inhibitors was generally well tolerated, with most ir-AEs being mild, suggesting that this treatment approach can be safely integrated in clinical practice for patients needing both therapies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Multicenter Evaluation of the Tolerability of Combined Treatment With PD-1 and CTLA-4 Immune Checkpoint Inhibitors and Palliative Radiation Therapy. Bang, A., Wilhite, TJ., Pike, LRG., et al.[2022]

In a review of 16 melanoma patients treated with ipilimumab and cranial radiation, the combination was found to be well tolerated and associated with a median survival of 14 months, suggesting potential benefits for patients with brain metastases.

There was a notable trend indicating that administering ipilimumab within three months of radiation may enhance the likelihood of improved responses in extra-cranial lesions, warranting further investigation into the timing of these treatments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Ipilmumab and cranial radiation in metastatic melanoma patients: a case series and review. Schoenfeld, JD., Mahadevan, A., Floyd, SR., et al.[2022]

In a phase 2 trial involving 20 patients with metastatic melanoma, combining stereotactic body radiation therapy (SBRT) with nivolumab resulted in an overall response rate of 45%, indicating that this combination may enhance treatment efficacy.

The treatment was generally well tolerated, with most adverse events being mild (grade 1 to 2), and some patients showed delayed responses after SBRT, suggesting that this approach could benefit those who initially do not respond to nivolumab alone.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Phase 2 Trial of Nivolumab Combined With Stereotactic Body Radiation Therapy in Patients With Metastatic or Locally Advanced Inoperable Melanoma. Sundahl, N., Seremet, T., Van Dorpe, J., et al.[2019]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12459094/

Efficacy outcomes between tarlatamab and real-world ... Tarlatamab, a bispecific T-cell engager immunotherapy, showed durable response with promising survival outcomes in patients with previously ...

2. ascopubs.org ascopubs.org/doi/10.1200/JCO.2025.43.16_suppl.e20120

Real world outcomes of patients treated with tarlatamab in ... Median time from CNS radiation and tarlatamab initiation was 4 months (range 3-28). Other characteristics, outcomes, and toxicity are presented ...

3. sciencedirect.com sciencedirect.com/science/article/pii/S152573042500052X

Real-World Outcomes of Tarlatamab in Small Cell Lung ... The objective response rate (ORR) was 23%, the median duration of response was 12.3 months with a disease control rate of 51.4%. The mPFS and mOS were 3.7 ...

4. esmo.org esmo.org/oncology-news/tarlatamab-prolongs-os-over-chemotherapy-among-patients-with-sclc-whose-disease-had-progressed-during-or-after-platinum-based-chemotherapy

Tarlatamab Prolongs OS Over Chemotherapy Among ... Treatment with tarlatamab resulted in significantly greater decreases in symptom scores than chemotherapy with respect to dyspnoea and cough. However, the ...

5. nejm.org nejm.org/doi/abs/10.1056/NEJMoa2502099

Tarlatamab in Small-Cell Lung Cancer after Platinum ... Treatment with tarlatamab resulted in significantly longer overall survival than chemotherapy (median, 13.6 months [95% confidence interval {CI} ...

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/40280845/

Real-World Outcomes of Tarlatamab in Small Cell Lung ... We observed higher rates of CRS and ICANS during the first treatment cycle suggesting that real-world safety outcomes may differ from clinical trial data.

7. nejm.org nejm.org/doi/full/10.1056/NEJMoa2307980

Tarlatamab for Patients with Previously Treated Small-Cell ... Tarlatamab, administered as a 10-mg dose every 2 weeks, showed antitumor activity with durable objective responses and promising survival outcomes

8. thelancet.com thelancet.com/journals/lanonc/article/PIIS1470-2045(25)00480-2/fulltext?rss=yes

Safety and activity of tarlatamab in combination with a PD ... The median number of tarlatamab doses was 18 (6–38). Median tarlatamab exposure was 35 weeks (8–75; appendix p 5). As of the data cutoff, 21 (24 ...

9. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0169500225006932

A pharmacovigilance study based on the FAERS database Clinical trial data demonstrate durable antitumor activity in SCLC patients, with the 10 mg dose cohort achieving a 40 % objective response rate ...

10. clinical-lung-cancer.com clinical-lung-cancer.com/article/S1525-7304(25)00052-X/fulltext

Real-World Outcomes of Tarlatamab in Small Cell ... In conclusion, tarlatamab showed promising antitumor activity in a heavily pretreated, real-world ES-SCLC population. However, we observed higher rates of CRS ...