Asymmetric Synthesis of (+)-<i>anti</i>- and (−)-<i>syn</i>-Mefloquine Hydrochloride

The asymmetric (er > 99:1) total synthesis of (+)-<i>anti</i>- and (−)-<i>syn</i>-mefloquine hydrochloride from a common intermediate is described. The Sharpless asymmetric dihydroxylation is the key asymmetric transformation used in the synthesis of this intermediate. It is carried out on an olefin that is accessed in three steps from commercially available materials, making the overall synthetic sequence very concise. The common diol intermediate derived from the Sharpless asymmetric dihydroxylation is converted into either a <i>trans</i>- or <i>cis</i>-epoxide, and these are subsequently converted to (+)-<i>anti</i>- and (−)-<i>syn</i>-mefloquine, respectively. X-ray crystallographic analysis of derivatives of (+)-<i>anti</i>- and (−)-<i>syn-</i>mefloquine is used to lay to rest a 40 year argument regarding the absolute stereochemistry of the mefloquines. A formal asymmetric (er > 99:1) synthesis of (+)-<i>anti</i>-mefloquine hydrochloride is also presented that uses a Sharpless asymmetric epoxidation as a key step

Asymmetric Synthesis of (+)-<i>anti</i>- and (−)-<i>syn</i>-Mefloquine Hydrochloride

The asymmetric (er > 99:1) total synthesis of (+)-<i>anti</i>- and (−)-<i>syn</i>-mefloquine hydrochloride from a common intermediate is described. The Sharpless asymmetric dihydroxylation is the key asymmetric transformation used in the synthesis of this intermediate. It is carried out on an olefin that is accessed in three steps from commercially available materials, making the overall synthetic sequence very concise. The common diol intermediate derived from the Sharpless asymmetric dihydroxylation is converted into either a <i>trans</i>- or <i>cis</i>-epoxide, and these are subsequently converted to (+)-<i>anti</i>- and (−)-<i>syn</i>-mefloquine, respectively. X-ray crystallographic analysis of derivatives of (+)-<i>anti</i>- and (−)-<i>syn-</i>mefloquine is used to lay to rest a 40 year argument regarding the absolute stereochemistry of the mefloquines. A formal asymmetric (er > 99:1) synthesis of (+)-<i>anti</i>-mefloquine hydrochloride is also presented that uses a Sharpless asymmetric epoxidation as a key step

Asymmetric Induction in Hydroacylation by Cooperative Iminium Ion–Transition-Metal Catalysis

A new strategy for the rhodium-catalyzed enantioselective hydroacylation is described. This has been achieved through the merger of iminium ion catalysis and transition-metal catalysis such that asymmetric induction derives from a readily accessible, inexpensive chiral nonracemic secondary amine catalyst rather than a chiral nonracemic phosphine as is typical of conventional asymmetric hydroacylation methods

Credentialing and Pharmacologically Targeting PTP4A3 Phosphatase as a Molecular Target for Ovarian Cancer

High grade serous ovarian cancer (OvCa) frequently becomes drug resistant and often recurs. Consequently, new drug targets and therapies are needed. Bioinformatics-based studies uncovered a relationship between high Protein Tyrosine Phosphatase of Regenerating Liver-3 (PRL3 also known as PTP4A3) expression and poor patient survival in both early and late stage OvCa. PTP4A3 mRNA levels were 5–20 fold higher in drug resistant or high grade serous OvCa cell lines compared to nonmalignant cells. JMS-053 is a potent allosteric small molecule PTP4A3 inhibitor and to explore further the role of PTP4A3 in OvCa, we synthesized and interrogated a series of JMS-053-based analogs in OvCa cell line-based phenotypic assays. While the JMS-053 analogs inhibit in vitro PTP4A3 enzyme activity, none were superior to JMS-053 in reducing high grade serous OvCa cell survival. Because PTP4A3 controls cell migration, we interrogated the effect of JMS-053 on this cancer-relevant process. Both JMS-053 and CRISPR/Cas9 PTP4A3 depletion blocked cell migration. The inhibition caused by JMS-053 required the presence of PTP4A3. JMS-053 caused additive or synergistic in vitro cytotoxicity when combined with paclitaxel and reduced in vivo OvCa dissemination. These results indicate the importance of PTP4A3 in OvCa and support further investigations of the lead inhibitor, JMS-053

The antimalarial drug mefloquine enhances TP53 premature termination codon readthrough by aminoglycoside G418.

Nonsense mutations constitute ~10% of TP53 mutations in cancer. They introduce a premature termination codon that gives rise to truncated p53 protein with impaired function. The aminoglycoside G418 can induce TP53 premature termination codon readthrough and thus increase cellular levels of full-length protein. Small molecule phthalimide derivatives that can enhance the readthrough activity of G418 have also been described. To determine whether readthrough enhancers exist among drugs that are already approved for use in humans, we tested seven antimalarial drugs for readthrough of the common R213X TP53 nonsense mutation in HDQ-P1 breast cancer cells. Mefloquine induced no TP53 readthrough activity as a single agent but it strongly potentiated readthrough by G418. The two enantiomers composing pharmaceutical mefloquine potentiated readthrough to similar levels in HDQ-P1 cells and also in SW900, NCI-H1688 and HCC1937 cancer cells with different TP53 nonsense mutations. Exposure to G418 and mefloquine increased p53 phosphorylation at Ser15 and P21 transcript levels following DNA damage, indicating p53 produced via readthrough was functional. Mefloquine does not appear to enhance readthrough via lysosomotropic effects as it did not significantly affect lysosomal pH, the cellular levels of G418 or its distribution in organellar or cytosolic fractions. The availability of a readthrough enhancer that is already approved for use in humans should facilitate study of the therapeutic potential of TP53 readthrough in preclinical cancer models

Post-progression outcomes of NSCLC patients with PD-L1 expression ≥ 50% receiving first-line single-agent pembrolizumab in a large multicentre real-world study

Background: Treatment sequencing with first-line immunotherapy, followed by second-line chemotherapy, is still a viable option for NSCLC patients with PD-L1 expression ≥50%. Methods: We evaluated post-progression treatment pathways in a large real-world cohort of metastatic NSCLC patients with PD-L1 expression ≥ 50% treated with first-line pembrolizumab monotherapy. Results: Overall, 974 patients were included. With a median follow-up of 22.7 months (95%CI: 21.6–38.2), the median overall survival (OS) of the entire population was 15.8 months (95%CI: 13.5–17.5; 548 events). At the data cutoff, among the 678 patients who experienced disease progression, 379 (55.9%) had not received any further treatment, and 359 patients (52.9%) had died. Patients who did not receive post-progression therapies were older (p = 0.0011), with a worse ECOG-PS (p < 0.0001) and were on corticosteroids prior to pembrolizumab (p = 0.0024). At disease progression, 198 patients (29.2%) received a switched approach and 101 (14.9%) received pembrolizumab ByPD either alone (64 [9.4%]) or in combination with local ablative treatments (37 [5.5%]) (LATs). After a random-case control matching according to ECOG-PS, CNS metastases, bone metastases, and (previous) best response to pembrolizumab, patients receiving pembrolizumab ByPD plus LATs were confirmed to have a significantly longer post-progression OS compared to patients receiving pembrolizumab ByPD alone 13.9 months versus 7.8 months (p = 0.0179) 241 patients (35.5%) among the 678 who had experienced PD, received a second-line systemic treatment (regardless of previous treatment beyond PD). As compared to first-line treatment commencement, patients’ features at the moment of second-line initiation showed a significantly higher proportion of patients aged under 70 years (p = 0.0244), with a poorer ECOG-PS (p < 0.0001) and having CNS (p = 0.0001), bone (p = 0.0266) and liver metastases (p = 0.0148). Conclusions: In the real-world scenario NSCLC patients with PD-L1 expression ≥50% treated with first-line single-agent pembrolizumab achieve worse outcomes as compared to the Keynote-024 trial. Poor post-progression outcomes are major determinants of the global results that should be considered when counselling patients for first-line treatment choices

Differential influence of antibiotic therapy and other medications on oncological outcomes of patients with non-small cell lung cancer treated with first-line pembrolizumab versus cytotoxic chemotherapy

Background: Some concomitant medications including antibiotics (ATB) have been reproducibly associated with worse survival following immune checkpoint inhibitors (ICIs) in unselected patients with non-small cell lung cancer (NSCLC) (according to programmed death-ligand 1 (PD-L1) expression and treatment line). Whether such relationship is causative or associative is matter of debate. Methods: We present the outcomes analysis according to concomitant baseline medications (prior to ICI initiation) with putative immune-modulatory effects in a large cohort of patients with metastatic NSCLC with a PD-L1 expression 6550%, receiving first-line pembrolizumab monotherapy. We also evaluated a control cohort of patients with metastatic NSCLC treated with first-line chemotherapy. The interaction between key medications and therapeutic modality (pembrolizumab vs chemotherapy) was validated in pooled multivariable analyses. Results: 950 and 595 patients were included in the pembrolizumab and chemotherapy cohorts, respectively. Corticosteroid and proton pump inhibitor (PPI) therapy but not ATB therapy was associated with poorer performance status at baseline in both the cohorts. No association with clinical outcomes was found according to baseline statin, aspirin, \u3b2-blocker and metformin within the pembrolizumab cohort. On the multivariable analysis, ATB emerged as a strong predictor of worse overall survival (OS) (HR=1.42 (95% CI 1.13 to 1.79); p=0.0024), and progression free survival (PFS) (HR=1.29 (95% CI 1.04 to 1.59); p=0.0192) in the pembrolizumab but not in the chemotherapy cohort. Corticosteroids were associated with shorter PFS (HR=1.69 (95%\u2009CI 1.42 to 2.03); p&lt;0.0001), and OS (HR=1.93 (95% CI 1.59 to 2.35); p&lt;0.0001) following pembrolizumab, and shorter PFS (HR=1.30 (95% CI 1.08 to 1.56), p=0.0046) and OS (HR=1.58 (95% CI 1.29 to 1.94), p&lt;0.0001), following chemotherapy. PPIs were associated with worse OS (HR=1.49 (95% CI 1.26 to 1.77); p&lt;0.0001) with pembrolizumab and shorter OS (HR=1.12 (95% CI 1.02 to 1.24), p=0.0139), with chemotherapy. At the pooled analysis, there was a statistically significant interaction with treatment (pembrolizumab vs chemotherapy) for corticosteroids (p=0.0020) and PPIs (p=0.0460) with respect to OS, for corticosteroids (p&lt;0.0001), ATB (p=0.0290), and PPIs (p=0.0487) with respect to PFS, and only corticosteroids (p=0.0033) with respect to objective response rate. Conclusion: In this study, we validate the significant negative impact of ATB on pembrolizumab monotherapy but not chemotherapy outcomes in NSCLC, producing further evidence about their underlying immune-modulatory effect. Even though the magnitude of the impact of corticosteroids and PPIs is significantly different across the cohorts, their effects might be driven by adverse disease features