Real-world treatment patterns, outcomes, and burden of early progression in small cell lung cancer (SCLC) in the US.

Treatment options for patients with SCLC are limited, and prognosis remains poor. Most patients develop resistance to or relapse after first-line (1L) therapies within the first year in both limited-stage (LS) and extensive-stage (ES). The economic burden of SCLC is not well characterized. This study evaluated recent real-world treatment patterns, clinical outcomes, and economic burden in LS- and ES-SCLC, including exploratory analyses by timing of progression after 1L treatment initiation.

Adults with LS-SCLC initiating 1L chemoradiotherapy (chemoRT) and ES-SCLC initiating 1L chemotherapy ± immunotherapy (chemoIO) were identified from ConcertAI Patient360 (Jan 2019–Jan 2025). Treatment patterns were described from 1L to 3L, including maintenance therapy use after chemoIO. Real-world overall survival (rwOS) was assessed from 1L initiation, separately for LS- and ES-SCLC.
Patients were further classified as early progressors (progression or death within 90 days after the last chemotherapy dose) or late progressors (progression or death after 90 days, or progression-free and clinically active at 90 days after the last chemotherapy dose). The 90-day threshold aligns with historically recognized chemotherapy-free interval definitions in SCLC. For early progressors, index was defined as 30 days before progression or death. To reduce immortal time bias, index for late progressors was randomly assigned to match the distribution of time from 1L initiation to index among early progressors. Post-index rwOS and all-cause medical costs (per patient per month [PPPM]) were compared between early vs late progressors using inverse probability of treatment weighting to adjust for baseline differences.

Among 794 patients with LS-SCLC (median age 68.2 years; 57.3% female), 93.5% received 1L platinum + etoposide with radiotherapy, 28.3% received second-line (2L) therapy, and 11.8% received third-line (3L) therapy. Among 1,946 patients with ES-SCLC (median age 67.5 years; 52.6% female), 70.6% received 1L platinum + etoposide + atezolizumab, 36.8% received 2L therapy, and 11.7% received 3L therapy.

Median rwOS from 1L initiation was 22.3 months in LS-SCLC and 8.0 months in ES-SCLC. Mean PPPM costs were $8,563 and $9,603 in LS- and ES-SCLC, respectively.

In exploratory analyses, patients with early progression was associated with shorter post-index rwOS (hazard ratio: 5.5 in LS-SCLC and 3.6 in ES-SCLC; p<0.001) and higher costs (mean PPPM difference: $7,664 and $4,391, respectively; p<0.001) compared to those with late progression.

Despite recent therapeutic advances, real-world outcomes in LS- and ES-SCLC remain poor. Early progression was associated with worse survival and higher economic burden. These findings highlight the substantial burden of rapid relapse and ongoing need for therapies that improve durability of response in SCLC.