Dostarlimab

In the United States, dostarlimab is indicated for the treatment of adults with mismatch repair deficient (dMMR) recurrent or advanced endometrial cancer, as determined by an FDA-approved test, that has progressed on or following prior treatment with a platinum-containing regimen.^[5][6][8] Platinum-based agents such as cisplatin, carboplatin and oxaliplatin are mainstays of treatment when it comes to cancer chemotherapy treatment.^[13] It is also indicated for the treatment of solid tumors.^[5]

In the European Union, dostarlimab is indicated as monotherapy for the treatment of adults with mismatch repair deficient (dMMR)/microsatellite instability-high (MSI H) recurrent or advanced endometrial cancer that has progressed on or following prior treatment with a platinum-containing regimen.^[8]

In August 2021, the US Food and Drug Administration (FDA) granted accelerated approval to dostarlimab for adults with mismatch repair deficient (dMMR) recurrent or advanced solid tumors, as determined by an FDA-approved test, that have progressed on or following prior treatment and who have no satisfactory alternative treatment options.^[14][15]

In July 2023, the FDA expanded the indication for dostarlimab, in combination with carboplatin and paclitaxel, followed by single-agent dostarlimab, for the treatment of primary advanced or recurrent endometrial cancer that is mismatch repair deficient, as determined by an FDA-approved test, or microsatellite instability-high.^[16][17] Efficacy was evaluated in RUBY (NCT03981796), a randomized, multicenter, double-blind, placebo-controlled trial.^[17] Efficacy was assessed in a pre-specified subgroup of 122 participants with dMMR/MSI-H primary advanced or recurrent EC.^[17] MMR/MSI tumor status was determined by local testing assays (IHC, PCR, or NGS), or central testing (IHC), using the Ventana MMR RxDx Panel, when local results were unavailable.^[17]

Endometrial cancer

Endometrial cancer is a disease where cancerous cells reside in the lining of the uterus (endometrium).^[18] There are four stages in endometrial cancer, ranging from staying settled in the endometrium to the cancer spreading to other organs in the body.^[18] This disease can be treated if discovered at the beginning of development.^[19] In those with chemoresistant MSI-high tumors, studies conducted on dostarlimab and pembrolizumab display promising results of the tumors reacting well to the therapies.^[19]

Solid tumors

Solid tumors are tumors that do not contain any liquid or cysts, which can occur in many places including bones, muscles and organs. The most common types of solid tumors are sarcomas and carcinomas.^[21] Dostarlimab can be used to treat recurrent or advance tumors for patients who have tried alternative treatment options.^[22]

Serious adverse reactions in >2% of patients included sepsis, acute kidney injury, urinary tract infection, abdominal pain, and fever (pyrexia).^[5][6]

Immune-mediated adverse reactions can occur including pneumonitis, colitis, hepatitis, endocrine disease (endocrinopathies), and nephritis.^[5][6]

The most common side effects reported while taking this medication during a trial were dyspnea, asthenia, fatigue, and nausea.^[23]

Symptoms of overdose are similar to the side effect profile of the medication, so it could involve significant immune-mediated reactions.^[24]

Immune-mediated adverse reactions

Dostarlimab is a monoclonal antibody that binds to PD-1 to block it from binding PD-1 ligands to remove inhibition of immune response.^[5] With this, it causes risk for immune-mediated adverse reactions.^[5] These reactions can be severe or fatal and occur in any part of the body: organs or tissues.^[5]

Examples of immune-mediated adverse reactions include immune-mediated pneumonitis, colitis, hepatitis, adrenal insufficiency, hypophysitis, thyroid disorders, nephritis with renal dysfunction, and dermatologic reactions.^[5]

Pregnancy and lactation

Dostarlimab can cause harm to a fetus.^[5] The death of the fetus can occur from the immune system's reaction to the fetus through the examination of its mechanism in animal studies.^[5] Dostarlimab is a human immunoglobulin G (IgG4), which could permeate through the placental barrier.^[5] This may risk harm to the developing fetus as the drug may be passed on from the mother.^[5]

Data is not available regarding the presence of dostarlimab in breastmilk.^[5]

Hepatotoxicity

Dostarlimab causes mild to moderate elevations to serum aminotransferase and alkaline phosphatase in 15-25% of recipients.^[24] Serum ALT elevation above five times the normal range occurs in 2-3% of recipients.^[24] Some people treated with dostarlimab can develop immune related liver injury.^[24]

Some symptoms of liver injury or acute liver failure can include jaundice, pain in the upper right abdomen, ascites, nausea/vomiting, and disorientation or confusion.^[25]

Dostarlimab is a humanized IgG4 monoclonal antibody that was derived from a mouse antibody which was humanized via Complementarity Determining Region (CDR) grafting.^[26] Its serum half-life is 25.4 days.^[5]

Other PD-1 antibodies included nivolumab (Opdivo) and pembrolizumab (Keytruda), both of which have uses in many different types of cancers which include classical Hodgkin lymphoma, renal cell carcinoma, and breast cancer.^[26] Another PD-1 antibody is cemiplimab (Libtayo) which was approved for treatment of squamous cell carcinoma, basal cell carcinoma and non-small cell lung cancer.^[26]

Mechanism of action

Dostarlimab binds to the PD-1 receptor, with high affinity, to block its activity with PD-1 ligands (PD-L1 and PD-L2).^[13][27] PD-1 is a co-inhibitory receptor that is an important checkpoint protein for regulating T-cell tolerance.^[5][26] When PD-1 is constantly stimulated by PD-1 ligands, which are highly expressed in cancer cells, it allows cancer cells to dodge T-cell mediated immune responses.^[26] Therefore, blocking the binding of PD-1 to these ligands can allow T-cells to function normally and prevent tumor cells from bypassing immune surveillance.^[26] In mouse tumor models, it was shown that inhibiting PD-1 activity decreased tumor growth.^[5]

Efficacy

In the Garnet Trial, dostarlimab achieved favorable results in decreasing the size of the tumor in those with endometrial cancer.^[28] The study observed people with endometrial cancer from seven different countries and the size of the tumor was reduced in 42% of the population studied.^[28]

Dostarlimab exhibits better efficacy than other PD-1 inhibitors, such as avelumab and durvalumab, in dMMR advanced endometrial cancers.^[29] Efficacy of the drug is measured by the response rate, which is 47% for dostarlimab.^[29]

In 2020, dostarlimab, a PD-1inhibitor, was undergoing phase I/II and phase III clinical trials.^[28][30][31]

In 2020, the manufacturer, Tesaro, announced preliminary successful results from the phase I/II GARNET study.^[28][32]

In 2020, the Garnet study announced that dostarlimab had promising potential to treat a specific subset of individuals with recurrent or advanced endometrial cancer.^[28]

In April 2021, dostarlimab was approved for the treatment of recurrent or advanced endometrial cancer with mismatch repair deficient (dMMR), which are genetic abnormalities that disrupt DNA repair, in individuals who had previously been treated with platinum-containing regimens.^[33]

In April 2021, the US Food and Drug Administration (FDA) granted accelerated approval to dostarlimab-gxly (Jemperli, GSK).^[6] Efficacy was evaluated based on cohort (A1) in Garnet Trial (NCT02715284), a multicenter, multicohort, open-label trial in participants with advanced solid tumors.^[6] The FDA approved dostarlimab based on evidence from the GARNET trial (NCT02715284) of 71 participants with advanced or recurrent endometrial cancer that was shown to be mismatch repair deficient (dMMR), and for which certain types of chemotherapy did not work or was no longer working.^[34] The cohort used for the approved indication was conducted at 40 sites in 7 countries in North America and Europe.^[34]

In 2022, an early clinical study of dostarlimab reported a 100% remission rate in 14 patients with rectal cancer who had mismatch repair deficiency, a type of genetic mutation that only affects 5-10% of cases.^[35][36][37]

In February 2023, the FDA approved dostarlimab-gxly (Jemperli, GlaxoSmithKline LLC) for adults with mismatch repair deficient (dMMR) recurrent or advanced endometrial cancer, as determined by an FDA-approved test, that has progressed on or following a prior platinum-containing regimen in any setting and are not candidates for curative surgery or radiation.^[7]

Dostarlimab is the international nonproprietary name (INN),^[38] and the United States Adopted Name (USAN).^[39]

Legal status

In February 2021, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a conditional marketing authorization for the medicinal product Jemperli, intended for the treatment of certain types of recurrent or advanced endometrial cancer.^[40] The applicant for this medicinal product is GSK (Ireland) Limited.^[40] Dostarlimab was approved for medical use in the European Union in April 2021.^[8]

Economics

In the United States, dostarlimab costs around US$11,000 per dose.^[41]

Among those who are insured, those who have Medicaid insurance are less likely to receive full care for gynecologic cancer.^[42] Those insured through private insurance still experience economical hardships while getting treatment.^[42] Uninsured patients do not tend to get screened regularly, which results in late diagnosis of the disease.^[42]

• "Dostarlimab for previously treated advanced or recurrent endometrial cancer with high microsatellite instability or mismatch repair deficiency". Technology appraisal guidance (Reference number:TA779). NICE.[1]
• Clinical trial number NCT02715284 for "Study of TSR-042, an Anti-programmed Cell Death-1 Receptor (PD-1) Monoclonal Antibody, in Participants With Advanced Solid Tumors (GARNET)" at ClinicalTrials.gov