Supplementary Tables S1 to S5 from Allosteric PI3Kα Inhibition Overcomes On-target Resistance to Orthosteric Inhibitors Mediated by Secondary <i>PIK3CA</i> Mutations

Table S1: Eligibility Criteria. Table S2: Genomic alterations within the PIK3CA pathway and other documented alterations for this study. Table S3: VAF of EOT alterations. Table S4: Comparison of Acquired PIK3CA mutations based on baseline activating mutation. Table S5: Comparison of Acquired PIK3CA mutations based on number of baseline activating PIK3CA mutations.</p

Supplementary Figures S1 to S11 from Allosteric PI3Kα Inhibition Overcomes On-target Resistance to Orthosteric Inhibitors Mediated by Secondary <i>PIK3CA</i> Mutations

Supplementary Figure S1: PI3K pathway activity in selected cases with acquired PTEN alteration. Supplementary Figure S2. Validation of AKT constructs expression in T47D cells. Supplementary Figure S3. AKT activating mutations confer resistance to PI3Ka inhibitors. Supplementary Figure S4: Free energy calculations predict resistance to orthosteric PI3K inhibitors due to specific double PIK3CA mutants. Supplementary Figure S5: Free energy perturbation predicts reduced binding of orthosteric PI3K inhibitors to double mutants. Supplementary Figure S6. Expression of PIK3CA mutations in T47D cells. Supplementary Figure S7. MCF7 cells expressing W780R or Q859H double mutants show differential response to PIK3CA orthosteric inhibitors. Supplementary Figure S8: Chemical structure of RLY-2608. Supplementary Figure S9: Surface plasmon resonance (SPR) binding assay. Supplementary Figure S10. Alpelisib shows reduced potency of downstream signaling inhibition in the presence of W780R or Q859H/K. Supplementary Figure S11. T47D cells expressing I817F or E726K double mutants do not show a differential response to inavolisib (A) or RLY-2608 (B).</p

Supplementary Tables S1 to S5 from Allosteric PI3Kα Inhibition Overcomes On-target Resistance to Orthosteric Inhibitors Mediated by Secondary <i>PIK3CA</i> Mutations

Table S1: Eligibility Criteria. Table S2: Genomic alterations within the PIK3CA pathway and other documented alterations for this study. Table S3: VAF of EOT alterations. Table S4: Comparison of Acquired PIK3CA mutations based on baseline activating mutation. Table S5: Comparison of Acquired PIK3CA mutations based on number of baseline activating PIK3CA mutations.</p

Supplementary Figures S1 to S11 from Allosteric PI3Kα Inhibition Overcomes On-target Resistance to Orthosteric Inhibitors Mediated by Secondary <i>PIK3CA</i> Mutations

Supplementary Figure S1: PI3K pathway activity in selected cases with acquired PTEN alteration. Supplementary Figure S2. Validation of AKT constructs expression in T47D cells. Supplementary Figure S3. AKT activating mutations confer resistance to PI3Ka inhibitors. Supplementary Figure S4: Free energy calculations predict resistance to orthosteric PI3K inhibitors due to specific double PIK3CA mutants. Supplementary Figure S5: Free energy perturbation predicts reduced binding of orthosteric PI3K inhibitors to double mutants. Supplementary Figure S6. Expression of PIK3CA mutations in T47D cells. Supplementary Figure S7. MCF7 cells expressing W780R or Q859H double mutants show differential response to PIK3CA orthosteric inhibitors. Supplementary Figure S8: Chemical structure of RLY-2608. Supplementary Figure S9: Surface plasmon resonance (SPR) binding assay. Supplementary Figure S10. Alpelisib shows reduced potency of downstream signaling inhibition in the presence of W780R or Q859H/K. Supplementary Figure S11. T47D cells expressing I817F or E726K double mutants do not show a differential response to inavolisib (A) or RLY-2608 (B).</p

Supplemental Text from Discovery and Clinical Proof-of-Concept of RLY-2608, a First-in-Class Mutant-Selective Allosteric PI3Kα Inhibitor That Decouples Antitumor Activity from Hyperinsulinemia

Synthesis of mutant-selective allosteric PI3Kα inhibitors</p

Figure S6 from Discovery and Clinical Proof-of-Concept of RLY-2608, a First-in-Class Mutant-Selective Allosteric PI3Kα Inhibitor That Decouples Antitumor Activity from Hyperinsulinemia

Varied levels of PI3Kα-dependency across cell lines</p

Figure S3 from Discovery and Clinical Proof-of-Concept of RLY-2608, a First-in-Class Mutant-Selective Allosteric PI3Kα Inhibitor That Decouples Antitumor Activity from Hyperinsulinemia

Binding kinetics and potency of [2] towards PI3Kα</p

Table S2 from Discovery and Clinical Proof-of-Concept of RLY-2608, a First-in-Class Mutant-Selective Allosteric PI3Kα Inhibitor That Decouples Antitumor Activity from Hyperinsulinemia

Time-dependence of biochemical inhibition and mutant selectivity of RLY-2608</p

Figure S4 from Discovery and Clinical Proof-of-Concept of RLY-2608, a First-in-Class Mutant-Selective Allosteric PI3Kα Inhibitor That Decouples Antitumor Activity from Hyperinsulinemia

Binding kinetics and potency of [1] towards tailless PI3Kα</p

Figure S1 from Discovery and Clinical Proof-of-Concept of RLY-2608, a First-in-Class Mutant-Selective Allosteric PI3Kα Inhibitor That Decouples Antitumor Activity from Hyperinsulinemia

Activation loop residues 937-954 are more disordered in mutant vs. wildtype PI3Kα</p