Ongoing Consolidative RT Trial May Support Efficacy Findings in SCLC

CancerNetwork^® spoke with James Ninia, MD, a third-year resident of radiation oncology at the Yale School of Medicine, about the next steps for researching radiotherapy modalities in patients with extensive-stage small cell lung cancer (ES-SCLC) following efficacy results for consolidative radiotherapy he presented at the 2024 American Society of Radiation Oncology (ASTRO) Annual Meeting.¹

Ninia began by highlighting an open trial that aims to address the same question he sought to answer in the study he presented as a secondary outcome. He then outlined the purpose of the trial, the phase 2/3 RAPTOR trial (NCT04402788), which will assess consolidative radiotherapy efficacy as a secondary measure.²

He explained that its main purpose was to assess whether the benefits of consolidated thoracic radiation present in the CREST trial (NTR1527) would still be applicable with immunotherapy.³ Similar to Ninia’s study, the RAPTOR trial is assessing whether progression-free survival (PFS) or overall survival (OS) benefits are seen with complete vs incomplete consolidative therapy for patients with ES-SCLC.

Ninia concluded by suggesting that the results he presented at ASTRO, although limited by factors including sample size, give reason for patients to enroll on the RAPTOR trial. He stated that patient enrollment may enable a better understanding of consolidative radiotherapy’s role in care for this indication.

The phase 2/3 RAPTOR trial is assessing the impact of adding radiation therapy to immunotherapy with atezolizumab (Tecentriq) in adult patients with ES-SCLC. The trial will randomly assign patients to receive atezolizumab alone or in combination with radiation therapy until disease progression or unacceptable toxicity.

The coprimary end points of the study are PFS and OS, and secondary end points include adverse effect incidence, PFS stratified by tumor burden, and OS stratified by tumor burden.

Transcript:

[It is] fortuitous that there is an open and ongoing clinical trial that is seeking to evaluate this question as one of its secondary objectives, prospectively. This goes by a couple different names––[it has] been called the phase 2/3 RAPTOR trial, or you might hear it referred to as NRG-LU007––this trial is open here at Yale, as well as at many other centers around the country.

The primary purpose of this trial is to see whether the benefits of consolidated thoracic radiation that were observed in the CREST trial still apply in this era now where many patients [with SCLC] are getting immunotherapy with atezolizumab. As a secondary objective of this trial, they are also looking to prospectively evaluate whether patients who [receive] complete consolidation have better OS or PFS than those who get incomplete consolidation; the same question that they are trying to evaluate prospectively.

We here at Yale had some pretty promising retrospective data [that are] limited by our relatively small sample size and some other limitations, but given that these results are relatively promising, it is a good idea for practitioners around the country to try to encourage their patients to consider enrolling on this trial so that we can better understand the impact of offering consolidated radiotherapy to our patients.

References

1. Ninia JG, Verma N, Laird JH, et al. Complete vs. incomplete consolidative radiotherapy in patients with extensive-stage small cell lung cancer. Presented at the 2024 American Society for Radiation Oncology (ASTRO) Annual Meeting; September 29 – October 2, 2024; Washington, DC. Poster 2109
2. Testing the addition of radiation therapy to the usual immune therapy treatment (atezolizumab) for extensive stage small cell lung cancer, the RAPTOR trial. ClinicalTrials.gov. Updated October 4, 2024. Accessed October 7, 2024. https://tinyurl.com/yc3zmz6e
3. Slotman BJ, Tinteren HV, Praag JO, et al. Use of thoracic radiotherapy for extensive stage small-cell lung cancer: a phase 3 randomised controlled trial. Lancet. 2015;385(9962):36-42. doi:10.1016/S0140-6736(14)61085-0