Abstract 918: Real-world clinical characteristics and treatment (tx) outcomes by co-mutation status in patients (pts) with KRAS G12C-mutated non-small cell lung cancer (NSCLC)

Background: KRAS mutations occur in ~30% of NSCLC and KRAS G12C is the most common subtype (~40%). Co-mutations can impact NSCLC prognosis and tx response.

Methods: This retrospective study used the nationwide (US-based) de-identified Flatiron Health-Foundation Medicine clinico-genomic database (FH-FMI CGDB; January 1, 2011 to March 31, 2022). De-identified data originated from ~280 US cancer clinics (~800 sites of care). This study is based on tissue-based assay (FoundationOne CDx). Pts were aged ≥18 years; had KRAS G12C-mutated, advanced/metastatic NSCLC, and had received ≥1 line of tx, with 1L tx initiated after October 1, 2016. Pts were categorized by presence (m) or absence (wt) of single co-mutations in STK11, KEAP1, or TP53; pts with EGFR, ALK, ROS1, BRAF, MET, or NTRK alterations were excluded. Key endpoints included overall survival (OS) and real-world progression-free survival (rwPFS). Statistical methods included a univariate Cox hazard model.

Results: Among 847 pts with KRAS G12C-mutated NSCLC, co-mutations of STK11 were seen in 24%, KEAP1 in 14%, and TP53 in 51%. Based on non-missing records (82%), low tumor mutational burden (<10 mut/Mb) was more frequent in the STK11m vs wt group (72% vs 55%; p<0.001), not significantly different in the KEAP1m vs wt group (53% vs 60%; p=0.145), and less frequent in pts with TP53m vs wt (50% vs 69%; p<0.001). Negative PD-L1 status (<1%) was more frequent in pts with STK11 (50% vs 18%; p<0.001) or KEAP1 (41% vs 23%; p<0.001) mutations, and less frequent in pts with TP53 mutations (15% vs 37%; p<0.001). STK11 or KEAP1 co-mutations were associated with shorter rwPFS and OS, particularly in pts treated with immunotherapy (IO)-based 1L tx (Table 1). TP53 status did not significantly impact pt outcomes in the 1L setting.

Conclusions: In this real-world analysis, STK11 or KEAP1 co-mutations were associated with PD-L1-negative tumors and poor outcomes with IO-based tx in KRAS G12C-mutated NSCLC.

Table 1. rwPFS and OS by co-mutation status, and OS by 1L treatment and co-mutation status rwPFS and OS by co-mutation status rwPFS All (N=846) STK11m (n=206) STK11wt (n=640) KEAP1m (n=121) KEAP1wt (n=725) TP53m (n=429) TP53wt (n=417) Median, months (95% CI) 5.0 (4.5-5.7) 4.0 (3.1-4.9) 5.6 (4.9-6.2) 3.8 (2.7-4.8) 5.6 (4.7-6.2) 5.3 (4.6-6.1) 4.7 (4.0-5.7) HR (95% CI); p value - 1.38 (1.16-1.64); <0.001 1.46 (1.18-1.80); <0.001 0.87 (0.75-1.01); 0.07 OS All (N=847) STK11m (n=206) STK11wt (n=641) KEAP1m (n=121) KEAP1wt (n=726) TP53m (n=429) TP53wt (n=418) Median, months (95% CI) 11.9 (10.2-14.3) 9.4 (7.2-13.8) 12.4 (10.8-15.0) 7.6 (5.4-9.4) 13.5 (11.0-15.1) 11.0 (9.2-14.4) 12.7 (10.4-15.3) HR (95% CI); p value - 1.40 (1.15-1.70); <0.001 1.59 (1.26-2.00); <0.001 0.98 (0.83-1.17); 0.85 OS by 1L treatment and co-mutation status IO + chemotherapy STK11m (n=106) STK11wt (n=228) KEAP1m (n=53) KEAP1wt (n=281) TP53m (n=162) TP53wt (n=172) Median, months (95% CI) 6.9 (4.5-9.4) 11.3 (9.0-14.8) 7.9 (4.5-10.3) 10.2 (7.7-12.9) 9.3 (6.6-11.9) 10.9 (7.2-14.0) HR (95% CI); p value 1.75 (1.33-2.31); <0.0001 1.60 (1.13-2.26); 0.01 1.04 (0.80-1.36); 0.75 IO monotherapy STK11m (n=33) STK11wt (n=181) KEAP1m (n=29) KEAP1wt (n=185) TP53m (n=111) TP53wt (n=103) Median, months (95% CI) 9.7 (2.8-16.9) 16.1 (10.7-23.3) 5.7 (3.9-14.3) 16.6 (10.8-23.0) 15.1 (9.1-22.4) 14.6 (8.9-23.0) HR (95% CI); p value 1.54 (0.97-2.46); 0.07 1.81 (1.12-2.90); 0.01 0.96 (0.68-1.37); 0.83 Chemotherapy only STK11m (n=56) STK11wt (n=188) KEAP1m (n=28) KEAP1wt (n=216) TP53m (n=130) TP53wt (n=114) Median, months (95% CI) 18.6 (10.2-22.8) 13.5 (9.5-15.3) 7.8 (5.0-17.4) 14.5 (11.1-16.3) 12.0 (8.9-16.0) 15.0 (11.1-19.5) HR (95% CI); p value 0.84 (0.57-1.25); 0.40 1.31 (0.82-2.10); 0.26 1.12 (0.81-1.54); 0.49 CI, confidence interval; HR, hazard ratio.

Citation Format: Marcelo V. Negrao, Wen-Hsing Wu, Colin R. Lindsay, Rafael Caparica, Vincent Prêtre, Yehrim Kang, Nydia Caro, Anna Farago, Fen Ye, Gilberto de Castro Jr. Real-world clinical characteristics and treatment (tx) outcomes by co-mutation status in patients (pts) with KRAS G12C-mutated non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 918.

First-in human, phase 1, dose-escalation pharmacokinetic and pharmacodynamic study of the oral dual PI3K and mTORC1/2 inhibitor PQR309 in patients with advanced solid tumors (SAKK 67/13)

BACKGROUND

PQR309 is an orally bioavailable, balanced pan-phosphatidylinositol-3-kinase (PI3K), mammalian target of rapamycin (mTOR) C1 and mTORC2 inhibitor.

PATIENTS AND METHODS

This is an accelerated titration, 3 + 3 dose-escalation, open-label phase I trial of continuous once-daily (OD) PQR309 administration to evaluate the safety, pharmacokinetics (PK) and pharmacodynamics in patients with advanced solid tumours. Primary objectives were to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D).

RESULTS

Twenty-eight patients were included in six dosing cohorts and treated at a daily PQR309 dose ranging from 10 to 150 mg. Common adverse events (AEs; ≥30% patients) included fatigue, hyperglycaemia, nausea, diarrhoea, constipation, rash, anorexia and vomiting. Grade (G) 3 or 4 drug-related AEs were seen in 13 (46%) and three (11%) patients, respectively. Dose-limiting toxicity (DLT) was observed in two patients at 100 mg OD (>14-d interruption in PQR309 due to G3 rash, G2 hyperbilirubinaemia, G4 suicide attempt; dose reduction due to G3 fatigue, G2 diarrhoea, G4 transaminitis) and one patient at 80 mg (G3 hyperglycaemia >7 d). PK shows fast absorption (T_max 1-2 h) and dose proportionality for C_max and area under the curve. A partial response in a patient with metastatic thymus cancer, 24% disease volume reduction in a patient with sinonasal cancer and stable disease for more than 16 weeks in a patient with clear cell Bartholin's gland cancer were observed.

CONCLUSION

The MTD and RP2D of PQR309 is 80 mg of orally OD. PK is dose-proportional. PD shows PI3K pathway phosphoprotein downregulation in paired tumour biopsies. Clinical activity was observed in patients with and without PI3K pathway dysregulation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov # NCT01940133.

mTORC1/autophagy-regulated MerTK in mutant BRAFV600 melanoma with acquired resistance to BRAF inhibition

BRAF inhibitors (BRAFi) and the combination therapy of BRAF and MEK inhibitors (MEKi) were recently approved for therapy of metastatic melanomas harbouring the oncogenic BRAFV600 mutation. Although these therapies have shown pronounced therapeutic efficacy, the limited durability of the response indicates an acquired drug resistance that still remains mechanistically poorly understood at the molecular level. We conducted transcriptome gene profiling in BRAFi-treated melanoma cells and identified that Mer tyrosine kinase (MerTK) is specifically upregulated. MerTK overexpression was demonstrated not only in melanomas resistant to BRAFi monotherapy (5 out of 10 samples from melanoma patients) but also in melanoma resistant to BRAFi+MEKi (1 out of 3), although MEKi alone does not affect MerTK. Mechanistically, BRAFi-induced activation of Zeb2 stimulates MerTK in BRAFV600 melanoma through mTORC1-triggered activation of autophagy. Co-targeting MerTK and BRAFV600 significantly reduced tumour burden in xenografted mice, which was pheno-copied by co-inhibition of autophagy and mutant BRAFV600.

Inhibition of Akt and other AGC kinases: A target for clinical cancer therapy?

AGC kinases have been identified to contribute to cancer development and progression. Currently, most AGC inhibitors in clinical development are Akt inhibitors such as MK-2206 or GDC-0068, which are known to promote cell growth arrest and to sensitize cancer cells to radiotherapy. Response rates in clinical trials with single agent Akt inhibitors are typically low. The observed adverse events are within the expected limits for compounds inhibiting the PI3K-mTOR axis. Preclinical and early clinical data for combination therapies are accumulating. Based on these data, several Akt inhibitors are about to enter phase 3 trials. Besides drugs that target Akt, p70S6K inhibitors have entered clinical development. Again, the response rates were rather low. In addition, relevant toxicities were identified, including a risk for coagulopathies with these compounds. Multi-AGC kinase inhibitors are also in early clinical development but the data is not sufficient yet to draw conclusions regarding their efficacy and side-effect profile. PKC inhibitors have been tested in the phase 3 setting but were found to lack efficacy. More trials with isoform-specific PKC inhibitors are expected. Taken together, therapies with AGC kinase inhibitors as single agents are unlikely to meet success. However, combination therapies and a precise stratification of patients according to the activation of signaling axes may increase the probability to see relevant efficacy with these compounds. The emergence of onco-immunotherapies holds some new challenges for these agents.

Abstract 2287: Final results of the pharmacodynamic (PD) data of PQR309-001, a first-in-human trial of a combined PI3K/mTOR inhibitor in advanced solid tumors

Background: PQR309 is a novel, oral, balanced pan-class 1 PI3K, mTORC1 and mTORC2 inhibitor. PQR309-001 was a first-in-man dose escalation study evaluating PQR309 in patients with advanced solid tumours.

The primary objective of the study was to establish the maximum tolerated dose (MTD) of PQR309, its safety and tolerability. Secondary objectives included characterization of PQR309 pharmacokinetics (PK) and pharmacodynamics (PD).

Methods: We investigated PQR309 treatment-induced PD, including changes of 16 PI3K-mTOR and MAPK associated phospho-proteins, and 84 mRNAs in serial tumor biopsies obtained from patients enrolled in study PQR309-001. 13 patients were eligible for PD analysis after histologic evaluation of fresh-frozen tissue. A solid-phase assay with phospho-specific antibodies was used for the investigation of PI3K/mTOR and MAPK signalling. RNA analysis was performed with an RTK/PI3K-specific RNA array.

Results: Under treatment with PQR309, phospho-Akt (p_T308 and p_S473), phospho-mTOR and phospho-S6 were significantly downregulated compared to baseline (p<0.05, Wilcoxon signed-rank test). Moreover, patients with radiographic tumor shrinkage (n = 7) had significantly stronger phospho-Akt (p_T308), phospho-mTOR and phospho-S6 reduction than patients whose tumor was growing (n = 6) (p<0.05, Mann-Whitney test). Importantly, ERK1/2 phosphorylation, as the readout of MAPK activity, was decreased overall with no statistically significant difference between shrinking and growing tumors. The analysis of mRNAs showed a trend towards upregulation of PDGFRA (3.2 times, not statistically significant) after 21 days of therapy with PQR309. Intriguingly, no consistent changes of other PI3K-related RNAs was observed.

Conclusion: PD assessments in tumour tissue samples from patients treated with PQR309 demonstrated a reduction of phosphorylation of direct targets for PQR309 (PI3K and mTOR) as well as downstream effectors of mTOR. Furthermore, the data indicate that downregulation of phospho-Akt (p_T308) and mTORC1 activity may be predictive of tumor shrinkage while upregulation of PDGFRA may represent a mechanism of resistance against PI3K/mTOR inhibition.

Citation Format: Andreas Wicki, Vincent Prêtre, Reto Ritschard, Nicholas Brown, Vincent Bize, Thomas Fabbro, Natasa Cmiljanovic, Sasa Dimitrijevic, Deborah Schmitz, Michael Stumm, Rebecca Kristeleit. Final results of the pharmacodynamic (PD) data of PQR309-001, a first-in-human trial of a combined PI3K/mTOR inhibitor in advanced solid tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2287.

Pre-existing antihypertensive treatment predicts early increase in blood pressure during bevacizumab therapy: the prospective AVALUE cohort study

BACKGROUND

Antiangiogenic therapy is routinely used in a variety of cancer entities. Hypertension is the most common side effect of all currently available antiangiogenic treatments.

PATIENTS AND METHODS

In this prospective observational clinical trial, we investigated risk factors for blood pressure elevation in patients exposed to an antiangiogenic agent and explored the correlation between hypertension and the duration of antiangiogenic treatment.

RESULTS

In 169 patients, pre-existing antihypertensive medication was the most prominent risk factor associated with increased blood pressure during therapy. Between visits 1 and 3, the median systolic blood pressure increased by 10.85 mmHg in patients with pre-existing hypertension receiving antihypertensive medication while it increased by only 2.69 mmHg in patients without hypertension. The median increase in diastolic pressure was 7.28 versus 0.11 mmHg in patients with versus without pre-existing hypertension. Increases in blood pressure occurred early (within 6 weeks of starting therapy). In spite of this significant increase in the blood pressure, no major bleeding events or other related complications were observed during antiangiogenic therapy.

CONCLUSIONS

Pre-existing hypertension and treatment with antihypertensive medication correlated with a more pronounced increase in blood pressure. Thus, intensified antihypertensive therapy might be warranted early during bevacizumab therapy in patients already receiving antihypertensive treatment.