OS defined as from randomization date to the date of death due to any cause. For each participant who is not known to have died as of the data-inclusion cutoff date for overall survival analysis, OS time was censored on the last date the participant is known to be alive.

All randomized participants. 81 participants were censored in the Abemaciclib arm and 56 participants were censored in the Erlotinib arm.

ORR was the percentage of participants achieving a best overall response (BOR) of complete response (CR) or partial response (PR) as per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. CR defined as the disappearance of all target and non-target lesions and no appearance of new lesions. PR defined as at least a 30% decrease in the sum of the longest diameters (LD) of target lesions (taking as reference the baseline sum LD), no progression of non-target lesions, and no appearance of new lesions.

All randomized participants.

PFS defined as the from randomization date to the first evidence of disease progression as defined by RECIST v1.1 or death from any cause. Progressive Disease (PD) was at least a 20% increase in the sum of the diameters of target lesions, with reference being the smallest sum on study and an absolute increase of at least 5 mm, or unequivocal progression of non-target lesions, or 1 or more new lesions. If a participant does not have a complete baseline disease assessment, then the PFS time was censored at the date of first dose, regardless of whether or not objectively determined disease progression or death has been observed for the participant. If a participant was not known to have died or have objective progression as of the data inclusion cutoff date for the analysis, the PFS time was censored at the last adequate tumor assessment date.

All randomized participants. 36 participants were censored in the abemaciclib arm and 24 were censored in the erlotinib arm.

The MDASI-LC included 22 items + 3 additional trial-specific items, resulting in 6 collected and reported single-construct scores including core symptoms (13-item), interference (6-item), lung cancer (3-item), and trial-specific single outcomes for headache, diarrhea, and rash. A 2-construct composite core + lung cancer symptom (16-item) score was calculated. Data for all 7 scores were collected by an 11-point numeric rating scale anchored at 0 (not present or does not interfere) and 10 (as bad as you can imagine or interfered completely). The measurement range was 10 (maximum score-minimum score). Mixed Model Repeated Measure (MMRM) regression with covariates for treatment, visit, treatment*visit, and baseline score predicted between-group Least Squares (LS) mean differences from baseline. Group-level negative change from baseline indicated group improvement.

All randomized participants for cycles which at least 25% of participants in each arm have a score. MDASI-LC population included all randomized participants who completed at least 1 baseline assessment followed by at least 1 MDASI-LC result.

PK is determined by the area under the plasma concentration versus time curve during 1 dosing interval at steady state

All randomized participants who received Abemaciclib and had evaluable PK data.

There are 5 response levels on a good-to-bad continuum of 1-5 corresponding to none, slight, moderate, severe, and extreme/unable to. The EuroQol-developed crosswalk method was used to convert the EQ-5D-5L,using United Kingdom (UK) weights, health dimensions(mobility, self-care, usual activities, pain/discomfort, and anxiety/depression) into a single index value; the dimensions are not separately scored. The index is marked missing when ≥1 dimensions are missing. The index scores for the response patterns were anchored on full health to dead with negative values assigned to response patterns/health states considered worse than death. The best pattern is assigned the index value of 1.0; the worst pattern is assigned an index value of -0.594. Between-group differences in regression-predicted change from baseline score were estimated for the index. LS Mean value was controlled for Treatment, visit, Treatment*Visit and baseline.

All randomized participants who received at least one dose of study drug and with a baseline and at least 1 post-baseline result.

Resource utilization is the percentage of participants who was hospitalized.

All randomized participants.