Abstract 4120743: MEK inhibition for recurring pulmonary valve stenosis in RASopathy patients
Bibliographic record
Abstract
Backgound: The RASopathies are developmental syndromes resulting from variants in the RAS/mitogen-activated protein (MAPK) cascade. The vast majority of RASopathy-causing variants lead to a gain of function in RAS-MAPK signaling. This has motivated compassionate use of MEK inhibition (MEKi) for rare, but potentially lethal complications such as hypertrophic cardiomyopathy and lymphatic disease. However, the most recurrent cardiac complication in RASopathies is pulmonary valve stenosis (PVS). PVS may require balloon valvuloplasty (BV) and can recur over time. Research question: Can MEKi be successfully used for recurrent PVS in RASopathy-patients? Aim: To report compassionate use of MEKi (trametinib) in recurring RASopathy-associated PVS. Method: Retrospective, single-center study at CHU Sainte Justine, Montreal, from 2021 to 2024. Results: After informed parental consent for off-label compassionate use of trametinib, four patients with recurrence of severe PVS after balloon valvuloplasty (>= 80 mmHg) had a total of 5 treatment episodes. Three patients were female, and one patient was male. The following genotypes were represented: Case 1, RIT1 A77V; case 2, PTPN11 N308D; case 3, RIT1 F82V, del22q11dist; case 4, PTPN11 Q110G, dup Xp22.13 (VUS), dup 16p11.2. Initial BV was carried out between three weeks and 10 months of age. Recurrence of PVS was noted between 4 days and 6 months after BV. Peak gradients at recurrence measured 72 -96 mmHg, and decreased to 40 – 64 mmHg (Dp -10 to -40 mmHg) at one to three months after treatment. Treatment had to be stopped in three cases for cutaneous side effects, with a rapid second recurrence in one case, which again responded to MEKi. PVS residual gradients at latest follow-up ranged from 30 – 69 mmHg. In all four patients, repeat catheter intervention or surgery could be avoided. In three out of four RASopathy patients with severe recurrent PVS after initial BV, we observe mild or moderate residual PVS. The patient with residual severe PS also carries a del22q11.2dist, which renders her haploinsufficient for LZTR1, a potential disease/treatment modifier within the RAS-MAPK cascade. Conclusion: Our results potentially expand the indications for MEKi in selected cases of RASopathy-associated recurrence of PVS and suggest an alternative to surgery or repeat catheterization. However, this case series is limited by the lack of an adequate contemporaneous, genotyped control cohort and its retrospective nature.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".