GSK's Jemperli (dostarlimab) accepted for review by Health Canada for patients with dMMR/MSI-H locally advanced rectal cancer

• Submission supported by AZUR-1 data showing a significant proportion of participants had no detectable signs of cancer one year or more after treatment completion
• If approved, Jemperli could potentially eliminate or delay the need for chemotherapy, radiation and surgery for people living with locally advanced rectal cancer
• Accepted for review under Health Canada's Notice of Compliance with Conditions (NOC/c) policy and Project Orbis pathway

MISSISSAUGA, ON, Sept. 24, 2026 /CNW/ -- GSK today announced that Health Canada has accepted Jemperli (dostarlimab) for review as a Supplemental New Drug Submission (SNDS) for patients with previously untreated stage II and III mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) locally advanced rectal cancer. The SNDS will be reviewed under Health Canada's NOC/c policy and the Project Orbis pathway; an international collaborative review initiative led by the US Food and Drug Administration's Oncology Center of Excellence for oncology products. The NOC/c policy provides an accelerated route for the review of drugs for serious, life-threatening or severely debilitating conditions where there is promising evidence of clinical effectiveness. Regulatory decisions remain independent in each Project Orbis participating country.

Rectal cancer, a type of colorectal cancer, accounts for roughly one-third of colorectal cancer cases¹. Colorectal cancer remains one of the most common and deadly cancers in the country, with an estimated 25,000 diagnoses and more than 9,000 related deaths expected this year. ² Approximately 5–10% of people with rectal cancer have the dMMR/MSI-H subtype.³ For patients with locally advanced rectal cancer, chemotherapy, radiation and surgery are established treatment approaches and, while often effective, can have lasting effects on bowel, urinary and sexual function, fertility and overall quality of life.^4,5,6 

"For people living with locally advanced rectal cancer, the disease -- and the current standard treatment journey -- can bring significant physical, emotional and quality-of-life burdens," said Dr. Michelle Horn, Country Medical Director, GSK Canada. "The possibility of a non-operative approach represents an important opportunity to help evolve the treatment paradigm for appropriate patients. We look forward to supporting the submission review to help address the needs of people affected by rectal cancer."

The submission is supported by positive data from the registrational phase II, single-arm AZUR-1 trial, which met its primary endpoint by demonstrating a meaningful and sustained clinical complete response rate at 12 months (cCR12), defined as no detectable signs of cancer for at least one year after treatment completion. The submission also included safety and tolerability data from AZUR-1, which were generally consistent with the known safety profile of dostarlimab. Data from AZUR-1 are planned for presentation at a scientific congress later in 2026.

The AZUR-1 results support the potential for dostarlimab, if approved, to become the first immunotherapy with the potential of eliminating or delaying the need for chemotherapy, radiation and surgery for some patients with dMMR/MSI-H locally advanced rectal cancer. These findings build on earlier research conducted with Memorial Sloan Kettering Cancer Center (MSKCC), which first demonstrated the potential for dostarlimab to achieve clinical complete responses without other treatments in patients with dMMR/MSI-H locally advanced rectal cancer.⁷

Jemperli's safety and efficacy in patients with previously untreated stage II or III mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) locally advanced rectal cancer remain under investigation and market authorization has not been granted. Jemperli is not approved for this use in Canada or any other country.

About stage II and III dMMR/MSI-H locally advanced rectal cancer
Rectal cancer affects around 770,000 people globally each year.⁸ In Canada, rectal cancer accounts for roughly one-third of colorectal cancer cases.¹ Around 5–10% of rectal cancers are mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H).³ These tumours have a specific genetic characteristic where they are unable to properly repair DNA damage, leading to an accumulation of mutations. This biological feature often makes them responsive to immunotherapies like dostarlimab.^9,10 These biomarkers are most commonly found in endometrial, colorectal and other gastrointestinal cancers, but can also be present in other solid tumours.¹¹

About AZUR-1
AZUR-1 is a global, open-label, single-arm, registrational phase II trial evaluating dostarlimab monotherapy in patients (n=154) with previously untreated stage II and III dMMR/MSI-H locally advanced rectal cancer. The trial was designed to assess sustained clinical complete responses for 12 months (cCR12) and determine whether dostarlimab alone could enable patients to avoid chemotherapy, radiation and surgery. Patients received nine cycles of dostarlimab over six months, administered as a 500mg intravenous infusion every three weeks. The safety and tolerability profile of dostarlimab was generally consistent with its well-characterized and manageable safety profile observed across solid tumours.

The AZUR-1 results represent a substantial improvement compared to the historical standard of care.¹² They build on earlier research conducted in collaboration with MSKCC, which first demonstrated the potential for dostarlimab to achieve clinical complete responses without other treatments in patients with dMMR/MSI-H locally advanced rectal cancer.

About Jemperli (dostarlimab for injection)
Jemperli is a programmed death receptor-1 (PD-1)-blocking antibody that binds to the PD-1 receptor and blocks its interaction with the PD-1 ligands PD-L1 and PD-L2.

As part of GSK's immuno-oncology research and development programme, Jemperli is being studied as monotherapy and in combination with other therapies across multiple tumour types, including gynaecologic, colorectal, and head and neck cancers. This clinical trial program reflects GSK's focus on exploring opportunities where immuno-oncology may help address areas of significant unmet need.

In Canada, Jemperli (dostarlimab for injection) is indicated in combination with carboplatin and paclitaxel for the treatment of all adult patients with primary advanced or first recurrent endometrial cancer who are candidates for systemic therapy. Jemperli is also approved as monotherapy for the treatment of adult patients with dMMR/MSI-H recurrent or advanced endometrial cancer that has progressed on or following prior treatment with a platinum-containing regimen.

GSK in oncology
Our ambition in oncology is to help increase overall quality of life, maximize survival and change the course of disease, expanding from our current focus on blood and women's cancers into lung and gastrointestinal cancers, as well as other solid tumours. This includes accelerating priority programmes such as antibody-drug conjugates Ris-Rez targeting B7-H3 and Mo-Rez targeting B7-H4, and velzatinib, a highly selective KIT tyrosine kinase inhibitor.

About GSK 
GSK is a global biopharma company with a purpose to unite science, technology, and talent to get ahead of disease together. Find out more at www.gsk.ca.

References

¹ Siegel RL, Wagle NS, Star J, Kratzer TB, Smith RA, Jemal A. Colorectal cancer statistics, 2026. CA Cancer J Clin. 2026 Mar-Apr;76(2):e70067. doi: 10.3322/caac.70067. PMID: 41769777; PMCID: PMC12951547. 

2 Canadian Cancer Society. Colorectal cancer statistics. 2026. Available at: https://cancer.ca/en/cancer-information/cancer-types/colorectal/statistics 

3 Cercek A, et al. Mismatch Repair-Deficient Rectal Cancer and Resistance to Neoadjuvant Chemotherapy. Clin Cancer Res. 2020 Jul 1;26(13):3271-3279. doi: 1158/1078-0432.CCR-19-3728. Epub 2020 Mar 6. PMID: 32144135; PMCID: PMC7348681

4 Cercek, A., Lumish, M., Sinopoli, J. et al. (2022) 'PD‑1 blockade in mismatch repair–deficient, locally advanced rectal cancer', New England Journal of Medicine, 386(25), pp. 2363–2376. Available at: https://www.nejm.org/doi/full/10.1056/NEJMoa2201445 

5 Negro, S. et al. (2025) 'Quality of life in rectal cancer treatments: a systematic review', Cancers, 17(14), 2310. Available at: https://www.mdpi.com/2072-6694/17/14/2310

6 Neibart, S.S. et al. (2020) 'Quality of life after radiotherapy for rectal cancer', Current Colorectal Cancer Reports, 16(1), pp. 1–10. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC7336840/

7 Cercek, A., Foote, M. B., Rousseau, B., Smith, J. J., Shia, J., Sinopoli, J., Weiss, J., Lumish, M., Temple, L., Patel, M., Wilde, C., Saltz, L. B., Argiles, G., Stadler, Z., Artz, O., Maron, S., Ku, G., Gu, P., Janjigian, Y. Y., … Diaz, L. A. (2025). Nonoperative Management of Mismatch Repair–Deficient Tumors. New England Journal of Medicine, 392(23), 2297–2308. https://doi.org/10.1056/nejmoa2404512 

8 International Agency for Research on Cancer (IARC) (2024) Rectum cancer fact sheet: GLOBOCAN 2022. World Health Organization. Available at: https://gco.iarc.who.int/media/globocan/factsheets/cancers/9-rectum-fact-sheet.pdf. Accessed August 2026

9 Andre T, Berton D, Curigliano G, et al. Antitumor Activity and Safety of Dostarlimab Monotherapy in Patients With Mismatch Repair Deficient Solid Tumors: A Nonrandomized Controlled Trial. JAMA Netw Open. 2023;6(11):e2341165. doi:10.1001/jamanetworkopen.2023.41165. 

10 Le DT, et al. PD-1 blockade in tumors with mismatch repair deficiency. N Engl J Med. 2015;372(26):2509-2520.

11 National Cancer Institute at the National Institutes of Health. Definition of mismatch repair deficiency. Accessed August 2026. Available at: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/mismatch-repair-deficiency

12 Cercek A, Roxburgh CS, Strombom P, et al. Adoption of Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer. JAMA Oncol. 2018;4(6):e180071. doi:10.1001/jamaoncol.2018.0071

Cautionary statement regarding forward-looking statements
GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described in the "Risk Factors" section in GSK's Annual Report on Form 20-F for 2025, and GSK's Q2 Results for 2026.

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