Daily Respiratory Research Analysis
A phase 3 randomized trial showed that add-on sotatercept markedly reduced death, transplant, or hospitalization in high-risk pulmonary arterial hypertension. In ALK-positive lung cancer, early resistance to first-line alectinib was frequently driven by off-target MET and NF2 alterations with EML4-ALK variant-specific patterns. An experimental ARDS study demonstrated that ventilator-induced lung injury depends on how mechanical power is distributed across tidal volume and respiratory rate, not m
Summary
A phase 3 randomized trial showed that add-on sotatercept markedly reduced death, transplant, or hospitalization in high-risk pulmonary arterial hypertension. In ALK-positive lung cancer, early resistance to first-line alectinib was frequently driven by off-target MET and NF2 alterations with EML4-ALK variant-specific patterns. An experimental ARDS study demonstrated that ventilator-induced lung injury depends on how mechanical power is distributed across tidal volume and respiratory rate, not mechanical power alone.
Research Themes
- Pulmonary hypertension therapeutics
- Targeted therapy resistance mechanisms in lung cancer
- Ventilator-induced lung injury and mechanical power components
Selected Articles
1. Sotatercept in Patients with Pulmonary Arterial Hypertension at High Risk for Death.
In a phase 3 trial of 172 high-risk PAH patients on maximal background therapy, add-on sotatercept reduced the composite of death, transplant, or PAH-related hospitalization by 76% versus placebo (HR 0.24). The trial stopped early for efficacy; epistaxis and telangiectasia were the most common adverse events.
Impact: This is a definitive, event-driven RCT showing substantial hard outcome benefits in a population with high unmet need, likely changing treatment algorithms for advanced PAH.
Clinical Implications: Consider sotatercept as add-on therapy for WHO FC III/IV PAH patients at high 1-year risk despite optimized background therapy, with monitoring for epistaxis and telangiectasia.
Key Findings
- Primary composite endpoint occurred in 17.4% with sotatercept vs 54.7% with placebo (HR 0.24, 95% CI 0.13–0.43).
- Reductions were seen across components: death (8.1% vs 15.1%), lung transplant (1.2% vs 7.0%), and hospitalization for PAH worsening (9.3% vs 50.0%).
- Trial stopped early at interim due to efficacy; epistaxis and telangiectasia were the most frequent adverse events.
Methodological Strengths
- Randomized, placebo-controlled, phase 3 design with hard, clinically meaningful endpoints.
- Event-driven analysis with prespecified interim stopping rules and multicenter enrollment.
Limitations
- Early stopping may overestimate effect size and limits long-term safety data.
- Modest sample size (n=172) and industry sponsorship may introduce biases.
Future Directions: Longer-term follow-up for survival and right heart remodeling, head-to-head or combination studies, and evaluation in broader PAH phenotypes.
BACKGROUND: Sotatercept improves exercise capacity and delays the time to clinical worsening in patients with World Health Organization (WHO) functional class II or III pulmonary arterial hypertension. The effects of add-on sotatercept in patients with advanced pulmonary arterial hypertension and a high risk of death are unclear. METHODS: In this phase 3 trial, we randomly assigned patients with pulmonary arterial hypertension (WHO functional class III or IV) and a high 1-year risk of death (Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management Lite 2 risk score, ≥9) who were receiving the maximum tolerated dose of background therapy to receive add-on sotatercept (starting dose, 0.3 mg per kilogram of body weight; escalated to target dose, 0.7 mg per kilogram) or placebo every 3 weeks. The primary end point was a composite of death from any cause, lung transplantation, or hospitalization (≥24 hours) for worsening pulmonary arterial hypertension, assessed in a time-to-first-event analysis. RESULTS: A total of 172 patients were included (86 each in the sotatercept and placebo groups). The trial was stopped early on the basis of the efficacy results of a prespecified interim analysis. At least one primary end-point event occurred in 15 patients (17.4%) in the sotatercept group and in 47 patients (54.7%) in the placebo group (hazard ratio, 0.24; 95% confidence interval, 0.13 to 0.43; P<0.001). Death from any cause occurred in 7 patients (8.1%) in the sotatercept group and in 13 patients (15.1%) in the placebo group; lung transplantation in 1 patient (1.2%) and 6 patients (7.0%), respectively; and hospitalization for worsening pulmonary arterial hypertension in 8 patients (9.3%) and 43 patients (50.0%). The most common adverse events with sotatercept were epistaxis and telangiectasia. CONCLUSIONS: Among high-risk adults with pulmonary arterial hypertension who were receiving the maximum tolerated dose of background therapy, treatment with sotatercept resulted in a lower risk of a composite of death from any cause, lung transplantation, or hospitalization (≥24 hours) for worsening pulmonary arterial hypertension than placebo. (Funded by Merck Sharp and Dohme, a subsidiary of Merck [Rahway, NJ]; ZENITH ClinicalTrials.gov number, NCT04896008.).
2. MET and NF2 alterations confer primary and early resistance to first-line alectinib treatment in ALK-positive non-small-cell lung cancer.
Targeted sequencing of 108 relapsed ALK+ NSCLC cases showed that within 6 months of first-line alectinib, off-target MET and NF2 alterations predominate, driving primary/early resistance. Resistance mechanisms are EML4-ALK variant-specific (v1 skewed to off-target; v3 to on-target). Mutation spectra after second-line therapy also differed by variant.
Impact: Defines early resistance biology with actionable targets (e.g., MET) and variant-specific patterns, informing adaptive molecular monitoring and rational combinations upfront.
Clinical Implications: Baseline and early on-treatment profiling (including MET/NF2) and EML4-ALK variant determination may guide surveillance and early combination strategies (e.g., MET inhibitors) to preempt resistance.
Key Findings
- Within 6 months of first-line alectinib, off-target MET and NF2 alterations were more frequent than on-target ALK changes, indicating primary/early resistance drivers.
- Resistance patterns differed by EML4-ALK variant: variant 1 had 50% off-target-driven resistance (no on-target contribution), whereas variant 3 had 46% on-target resistance.
- After second-line therapy, common mutations were L1196M (42%) and G1269A (25%) in v1, and G1202R in 45% of v3 tumors.
Methodological Strengths
- Cohort of 108 relapsed patients with systematic targeted sequencing across first- and second-line settings.
- Granular analysis by EML4-ALK variants enabling biologically meaningful stratification.
Limitations
- Observational design with potential selection and treatment heterogeneity.
- Lack of functional validation and limited prospective correlation with combination treatment outcomes.
Future Directions: Prospective trials testing early MET-targeted combinations based on baseline/early alterations and variant-informed adaptive monitoring (including liquid biopsy).
Although first-line alectinib has prolonged survival in ALK-mutated non-small-cell lung cancers (NSCLCs), the response to treatment varies among patients, and the primary/early development of alectinib resistance mechanisms is still not fully understood. Here, we analyzed molecular profiles of 108 alectinib-treated patients (first-line and second-line after crizotinib) with confirmed relapse by targeted sequencing of cancer-related genes. After first-line treatment, off-target MET and NF2 alterations were more frequent than on-target alterations within the first 6 months, causing primary or early resistance. Conversely, on-target alterations became prevalent after 1 year of first-line alectinib treatment and predominantly after second-line. The incidence of acquired resistance also depended on EML4-ALK variants. In variant 1 (v1), off-target alterations were responsible for 50% of resistance cases after first-line alectinib therapy, whereas on-target mutations had no contribution in this subgroup. In variant 3 (v3), on-target alterations resulted in 46% of resistance cases, whereas only 18% were caused by off-target mutations. After second-line treatment, the most common mutations in v1 were L1196M (42%) and G1269A (25%), while G1202R was detected in 45% of v3 tumors. These findings emphasize the importance of stratifying resistance mechanisms to guide tailored treatment for ALK-positive NSCLCs.
3. Effects of Similar Mechanical Power Resulting From Different Combinations of Respiratory Variables on Lung Damage in Experimental Acute Respiratory Distress Syndrome.
In LPS-induced ARDS rats ventilated for 80 minutes at matched mechanical power, higher tidal volume/lower respiratory rate settings produced greater overdistension, edema, and biomarker evidence of epithelial, endothelial, and matrix injury than low Vt/high RR. Thus, VILI depends on how mechanical power is delivered, not its magnitude alone.
Impact: Challenges the prevailing use of mechanical power as a unitary target by demonstrating that its components (Vt vs RR) differentially drive injury, refining lung-protective ventilation concepts.
Clinical Implications: When titrating ventilator settings, prefer lower tidal volumes even if mechanical power is held constant; prioritize minimizing driving/plateau pressures to limit cyclical stress.
Key Findings
- At equal mechanical power, very-high Vt/very-low RR caused significantly greater overdistension, edema, and injury biomarkers than low Vt/high RR.
- Plateau and driving pressures rose progressively from low Vt/high RR to very-high Vt/very-low RR, paralleling injury severity.
- Markers of inflammation (IL-6), stretch (amphiregulin), epithelial damage (SP-B), endothelial injury (VCAM-1, ANGPT2), and ECM damage (versican, syndecan) were highest in the very-high Vt arm.
Methodological Strengths
- Controlled experimental ARDS model with predefined ventilation strategies achieving matched mechanical power.
- Comprehensive multiscale readouts: histopathology and molecular biomarkers for epithelial, endothelial, and ECM injury.
Limitations
- Animal model with short ventilation duration (80 minutes), limiting direct clinical generalizability.
- Single low PEEP and specific ARDS induction method may not reflect heterogeneous patient phenotypes.
Future Directions: Translational studies in large animals and clinical trials to test ventilation protocols that constrain driving/plateau pressures at a given mechanical power.
OBJECTIVES: Mechanical power is a crucial concept in understanding ventilator-induced lung injury (VILI). We adopted the null hypothesis that under the same mechanical power, resulting from combinations of different static and dynamic variables-some with high stress per cycle and others without-would inflict similar degrees of damage on lung epithelial and endothelial cells as well as on the extracellular matrix in experimental acute respiratory distress syndrome (ARDS). To test this hypothesis, we varied tidal volume (V t ), which correlates with the stretching force per cycle, while adjusting respiratory rate (RR) to yield similar mechanical power values for identical durations across all experimental groups. DESIGN: Animal study. SETTING: Laboratory investigation. SUBJECTS: Thirty male Wistar rats (333 ± 26 g). INTERVENTIONS: Twenty-four hours after intratracheal administration of Escherichia coli lipopolysaccharide, animals were anesthetized and mechanically ventilated (positive end-expiratory pressure = 3 cm H 2 O) with combination of V t and RR sufficient to induce similar mechanical power ( n = 8/group): V t = 6 mL/kg, RR = 140 breaths/minute (low V t -high RR [LVT-HRR]); V t = 12 mL/kg, RR = 70 breaths/minute (high V t -low RR [HVT-LRR]); and V t = 18 mL/kg, RR = 50 breaths/minute (very-high V t -very-low RR [VHVT-VLRR]). All groups were ventilated for 80 minutes. A control group, not subjected to mechanical ventilation (MV), was used for molecular biology analyses. MEASUREMENTS AND MAIN RESULTS: After 80 minutes of MV, lung overdistension, alveolar/interstitial edema, fractional area of E-cadherin, and biomarkers of lung inflammation (interleukin-6), lung stretch (amphiregulin), damage to epithelial (surfactant protein B) and endothelial cells (vascular cell adhesion molecule 1 and angiopoietin-2), and extracellular matrix (versican and syndecan) were higher in group VHVT-VLRR than LVT-HRR. Plateau pressure and driving pressure increased progressively from LVT-HRR to HVT-LRR and VHVT-VLRR. CONCLUSIONS: In the current experimental model of ARDS, mechanical power alone is insufficient to account for VILI. Instead, the manner in which its components are applied determines the extent of injury at a given mechanical power value.