4088 Background: Class-specific AEs occurring with tyrosine kinase inhibitors have been associated with improved efficacy outcomes in several tumor types including aHCC. In the phase 3 CELESTIAL trial (NCT01908426), C, an inhibitor of VEGFR, MET, and AXL, improved overall survival (OS) and progression-free survival (PFS) vs placebo (P) in pts with previously treated aHCC. Here, we retrospectively evaluate the association of palmar-plantar erythrodysaesthesia (PPE) and hypertension (HTN) with OS and PFS for C in the CELESTIAL trial. Methods: 707 pts with aHCC were randomized 2:1 to receive 60 mg C or P once daily. Eligible pts had Child-Pugh score A, ECOG PS ≤1, must have received prior sorafenib, and could have received up to two prior regimens of systemic therapy for HCC. OS and PFS with C were evaluated for pts with any grade PPE or grade ≥3 HTN within the first 8 weeks of study treatment. Results: Overall, 374 (80%) pts in the C arm and 179 (76%) pts in the P arm completed ≥8 weeks of treatment. In the first 8 weeks, 188 (40%) of C-treated pts developed any grade PPE vs 11 (5%) of P-treated pts, and 61 (13%) of C-treated pts developed grade ≥3 HTN vs 3 (1%) of P-treated pts. Median OS with C was 14.4 mo for pts with any grade PPE vs 8.4 mo for pts without PPE (HR 0.59, 95% CI 0.47-0.74), and median PFS with C was 6.5 mo vs 3.7 mo, respectively (HR 0.63, 95% CI 0.51-0.78). Median OS with C was 16.1 mo for pts with grade ≥3 HTN vs 9.5 mo for pts without grade ≥3 HTN (HR 0.56, 95% CI 0.39-0.80), and median PFS with C was 7.4 mo vs 4.4 mo, respectively (HR 0.59, 95% CI 0.43-0.82). Some imbalances in baseline characteristics were present. Pts with PPE had better ECOG PS (60% vs 47% ECOG 0), better liver function (48% vs 34% ALBI grade 1), and less macrovascular invasion (24% vs 30%) than those without. Likewise, pts with grade ≥3 HTN had better ECOG PS (61% vs 51% ECOG 0), better liver function (56% vs 37% ALBI grade 1), and less macrovascular invasion (20% vs 29%) than those without. Conclusions: The development of PPE or grade ≥3 HTN with C was associated with prolonged OS and PFS in pts with previously treated aHCC although some imbalances in baseline characteristics between comparator groups were present. Clinical trial information: NCT01908426.