Chugai Pharmaceutical has submitted a regulatory application to Japan's Ministry of Health, Labour and Welfare (MHLW) seeking approval for Tecentriq (atezolizumab) as a treatment for thymic carcinoma. The application, which will undergo priority review, aims to expand treatment options for this rare and aggressive form of cancer.
The humanized anti-PD-L1 monoclonal antibody received orphan drug designation for thymic carcinoma from the MHLW on March 31, 2025, underscoring the significant unmet medical need for effective therapies in this indication.
"Thymic carcinoma is a rare cancer with poor prognosis after recurrence, and there is a need for new treatment options," said Dr. Osamu Okuda, President and CEO of Chugai Pharmaceutical. "We are working to obtain approval so that Tecentriq that demonstrated favorable efficacy in combination with standard chemotherapy can be delivered to patients as soon as possible as a new therapeutic option for thymic carcinoma."
Phase II MARBLE Study Results
The regulatory filing is supported by data from the investigator-initiated Phase II MARBLE study, which evaluated Tecentriq in combination with carboplatin and paclitaxel as first-line treatment for patients with unresectable thymic carcinoma.
The multicenter, open-label, single-arm study enrolled 48 Japanese patients aged 20 years or older with unresectable or advanced recurrent thymic carcinoma. The trial achieved its primary endpoint with an overall response rate of 56.3% (95% CI: 41.2-70.5), demonstrating significant clinical benefit.
Secondary endpoints included progression-free survival, overall survival, and safety assessments. While specific data on survival outcomes were not disclosed, the safety profile aligned with the known profiles of the individual components of the combination regimen.
Safety Profile
Common adverse reactions observed in the MARBLE study included:
- Peripheral sensory neuropathy
- Alopecia
- Constipation
- Anemia
- Decreased white blood cell count
- Nausea
- Maculopapular rash
- Neutropenia
- Decreased neutrophil count
- Decreased appetite
- Fatigue
- Arthralgia
Investigators reported that the safety profile was consistent with the established safety profiles of Tecentriq, carboplatin, and paclitaxel, with no new safety signals identified.
Understanding Thymic Carcinoma
Thymic carcinoma is a rare malignancy that develops from the epithelial cells of the thymus, an organ that plays a crucial role in T-lymphocyte maturation. The disease is characterized by cellular atypia and aggressive behavior.
The annual incidence in Japan is estimated at approximately 0.29 cases per 100,000 people. For patients with unresectable disease, prognosis remains poor, highlighting the urgent need for novel therapeutic approaches.
Tecentriq's Mechanism and Current Approvals
Tecentriq functions as a cancer immune checkpoint inhibitor by targeting PD-L1, a protein expressed on tumor cells and tumor-infiltrating immune cells. By blocking the interaction between PD-L1 and its receptors (PD-1 and B7.1) on T cells, Tecentriq may enable the activation of T cells and enhance immune responses against cancer cells.
The drug first launched in Japan in April 2018 and has since received approval for five indications:
- Extensive-stage small cell lung cancer
- Non-small cell lung cancer
- Breast cancer
- Hepatocellular carcinoma
- Alveolar soft part sarcoma
If approved for thymic carcinoma, this would mark Tecentriq's sixth indication in Japan, further expanding treatment options for patients with rare and difficult-to-treat malignancies.
Commitment to Oncology Innovation
Chugai Pharmaceutical, recognized as a leading company in oncology research and development, continues to focus on addressing unmet medical needs in cancer treatment through innovative medicines.
The company's expertise in antibody engineering and commitment to developing targeted therapies has positioned it as a significant contributor to advancing cancer care in Japan and globally.
As the regulatory review progresses, healthcare professionals and patients await a potential new option for managing thymic carcinoma, a rare cancer with limited treatment alternatives.
