What the trial was testing
The ARROW enrolled 590 patients with lung cancer. The study was sponsored by Hoffmann-La Roche and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was an early-stage trial — researchers are still confirming safety and getting an early look at how well the treatment works. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.
What the results showed
61-70% tumor response rates in RET-fusion lung cancer.
The Lancet Oncology · 2021 · NCT03037385
These findings — that tumor response rates in pretreated and untreated RET-fusion lung cancer — were published in the The Lancet Oncology and represent the headline result of the study.
Researchers tracked outcomes across 590 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.
What this means for patients
For patients with lung cancer, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.
What you can do now
Pralsetinib was originally FDA-approved for RET-fusion lung cancer but Genentech voluntarily withdrew the U.S. approval in 2024. Selpercatinib (Retevmo) is FDA-approved and available now for the same indication and is the standard targeted choice. Ask an oncologist about RET fusion testing if you have lung cancer.
Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.
Open lung cancer trials
Phase 3 Trial of Tarlatamab (SC vs IV) in Extensive-Stage Small Cell Lung Cancer After Platinum Based First-line Chemotherapy (ES-SCLC)
The primary objective of this study is to demonstrate non-inferiority in pharmacokinetic (PK) parameters of subcutaneous (SC) vs intravenous (IV) tarlatamab administration and to characterize the efficacy, safety, and tolerability of SC tarlatamab in participants with relapsed extensive-stage small-cell lung cancer (ES-SCLC) after platinum-based chemotherapy.
Sleep Disorders and Tumor Immune Microenvironment
Title: Impact of Sleep Disorders on Tumor Immune Microenvironment and Clinical Outcomes in Lung Cancer: A Prospective Cohort Study Objective: This prospective study aims to investigate the causal relationship between sleep disorders (e.g., insomnia, obstructive sleep apnea \[OSA\]) and alterations in the tumor immune microenvironment (TIME) in lung cancer patients, and to evaluate their joint effects on immunotherapy response and long-term prognosis. Study Design: Prospective observational cohort study with 3-year follow-up. Participants: Newly diagnosed primary lung cancer patients (NSCLC/SCLC) prior to treatment initiation (n = 400, target sample size\*). Exposure Groups: Stratified by sleep disorder status (confirmed via polysomnography \[OSA\] and validated questionnaires \[e.g., PSQI ≥7 for insomnia\]).