RESUMO
Treatment options for multiple myeloma (MM) at 1st relapse are expanding. The current study compared common 2nd line regimens administered in a real-world setting. MM patients registered in Maccabi health care services and treated with second line therapy during 2014-2020 were evaluated, analyzing factors affecting time to third line therapy (TT3T). The study included 500 MM patients, previously treated with proteasome inhibitor (PI)-based induction. Median age at second line treatment was 68.5 years (IQR: 61.6-76.4). Most patients received a triplet based induction composed of PI (n = 471, 94.2%), with (n = 71) or without IMID (n = 400), followed by second line treatment composed of lenalidomide-dexamethasone (RD) (n = 225, 45%) or lenalidomide-dexamethasone-daratumumab (RD-Dara (n = 104, 20.8%)). Multivariable analysis confirmed treatment type (RD-Dara vs. IMID) to be associated with a lower risk to progress to third line therapy; (HR = 0.5, 95% CI 0.3-0.86, p = 0.012). Within a median follow-up period of 22.5 months (intraquartile range 11.1-39.4 m), median TT3T was not reached in patients receiving RD-Dara vs. 32.4 months (95% CI 18.0-46.8 m) with IMID, 18 months (95% CI 10.4-25.6 m) with IMID-PI and 12.1 months (95% CI 5.6-18.7 m) with PI-based regimen. In contrast, PI vs. IMID-based therapy and increased body weight were associated with a higher likelihood of progression (HR = 2.56 (95% CI 1.49-4.42); HR = 1.43, (95% CI 0.96-2.14), p = 0.08). To conclude, second line therapy with RD-Dara was associated with a significantly longer TT3T compared with IMID-based regimen, longer than obtained with PI-IMID and PI-based regimens, in patients treated outside clinical studies and previously exposed to bortezomib.
RESUMO
Approximately 20% of plant genes possess upstream open-reading frames (uORFs). The effect of uORFs on gene expression has mainly been studied at the translational level. Very little is known about the impact of plant uORFs on transcript content through the nonsense-mediated mRNA decay (NMD) pathway, which degrades transcripts bearing premature termination codons (PTCs). Here we examine the impact of the uORF of the Arabidopsis AtMHX gene on transcript accumulation. The suggestion that this uORF exposes transcripts containing it to NMD is supported by (i) the increase in transcript levels upon eliminating the uORF from constructs containing it, (ii) experiments with a modified uORF-peptide, which excluded peptide-specific degradation mechanisms, (iii) the increase in levels of the native AtMHX transcript upon treatment with cycloheximide, which inhibits translation and blocks NMD, and (iv) the sensitivity of transcripts containing the uORF of AtMHX to the presence of introns. We also showed that introns can increase NMD efficiency not only in transcripts having relatively short 3' untranslated regions (UTRs), but also in uORF-containing transcripts. AtMHX transcript levels were almost unaltered in mutants of the NMD factors UPF3 and UPF1. Possible reasons, including the existence of a NMD-compensatory mechanism, are discussed. Interestingly, the levels of UPF3 transcript were higher in upf1 mutants, suggesting a compensatory mechanism that links weak function of the NMD machinery to increased expression of UPF3. Our findings highlight that uORFs, which are abundant in plants, can not only inhibit translation but also strongly affect transcript accumulation.
