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Dostarlimab / jemperli for treating advanced or recurrent endometrial cancer with high microsatellite instability or mismatch repair deficiency

This rating has a newer version, as of May 2025 — read the current report. This page stays on the record as originally published.

As of March 2022, MARA’s assessment finds Dostarlimab / Jemperli’s reimbursement risk concentrated in patient population and subgroups, with care pathway integration a strength; the current MARA Rating and full rationale are available in the report.

The assessment also weighs resource use and cost implications: what the drug adds to, or removes from, the wider bill beyond its own price — administration, monitoring, hospital time. The strength recorded in care pathway integration carries weight because that domain asks how the drug fits into the way care is organised today; a treatment that demands new infrastructure or displaces an established pathway faces extra scrutiny.

Oncology

This rating sits within MARA’s Oncology coverage, alongside 153 other independently assessed treatments in the same area.

What payers will ask

Is the clinical benefit the kind payers reward? — Clinical effectiveness

The clinical evidence for dostarlimab primarily comes from the ongoing GARNET trial, which is a single-arm study. While it suggests that dostarlimab may improve progression-free survival and overall survival compared to current treatments, the lack of direct comparisons and the immaturity of the data lead to significant uncertainty. The committee noted that indirect comparisons with other treatments are highly uncertain due to differences in study populations.

Does the economic case hold at the expected price? — Cost effectiveness

The economic model suggests that dostarlimab has the potential to be cost-effective, but the committee highlighted that the ICER is uncertain due to the immaturity of the trial data and the reliance on indirect comparisons. The ICER was reported at £38,363 per QALY, which is within acceptable limits, but the committee expressed concerns about the robustness of this estimate.

Is there quality-of-life evidence payers weigh? — Quality of life

Patient experts indicated that dostarlimab is associated with fewer serious adverse events compared to chemotherapy, which is expected to improve quality of life. The treatment’s shorter administration time also reduces the treatment burden, contributing positively to HRQoL. However, the evidence is primarily anecdotal and lacks robust quantitative data.

Does the safety profile hold up for payers? — Safety and Adverse Effects

Dostarlimab is reported to have a manageable adverse event profile, with lower rates of serious adverse events compared to standard chemotherapy. The clinical experts noted that adverse events were generally low grade, supporting a favorable safety profile.

Was the drug compared against what payers expect? — Comparator Selection

The evidence for dostarlimab lacks direct comparisons with standard treatments, relying instead on indirect treatment comparisons that are fraught with uncertainty. The committee acknowledged that while KEYNOTE-775 provides relevant comparator data, the absence of a biomarker-matched comparator arm in GARNET limits the robustness of the evidence.

Is the population defined the way payers need it? — Patient Population and Subgroups

The GARNET trial population is somewhat representative of the intended patient population, but there are concerns regarding the generalizability of the results due to the lack of biomarker data in the RWE subgroup. The committee noted significant differences in patient characteristics between the GARNET and RWE populations.

Does the drug fit how care is delivered and paid for? — Care Pathway Integration

Dostarlimab can be integrated into existing care pathways with minor adjustments, primarily due to its shorter administration time compared to traditional chemotherapy. This makes it a more convenient option for patients, which is a positive aspect for integration into clinical practice.

Are the wider system costs understood? — Resource Use and Cost Implications

While dostarlimab is expected to have a manageable budget impact, the committee raised concerns about the overall resource burden due to uncertainties in the economic model and the need for further data collection to confirm cost-effectiveness.

Would the evidence survive payer scrutiny? — Evidence Quality and Robustness

The evidence base is primarily derived from a single-arm trial, which presents limitations in terms of robustness and potential biases. The committee noted that while the GARNET trial provides some insights, the lack of direct comparative data and the ongoing nature of the trial contribute to significant uncertainty.

How exposed is the case to uncertainty? — Uncertainty, Sensitivity, and Broader Impacts

There is considerable uncertainty surrounding the long-term outcomes and cost-effectiveness of dostarlimab due to the immaturity of the trial data and the reliance on indirect comparisons. The committee emphasized the need for further data collection to address these uncertainties.

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