Keytruda expands bladder and ovarian cancer indications

Approved for perioperative treatment of muscle-invasive bladder cancer

Added as a new immunotherapy option for platinum-resistant ovarian cancer

Immuno-oncology drug Keytruda

MSD's immuno-oncology therapy Keytruda (pembrolizumab) has secured additional approvals in South Korea for the treatment of muscle-invasive bladder cancer (MIBC) and platinum-resistant ovarian cancer.

The approval carries significance as it provides a new perioperative treatment option for bladder cancer patients who are ineligible for cisplatin-based chemotherapy, as well as an additional immunotherapy option for patients with platinum-resistant ovarian cancer, where treatment choices have been limited.

MSD Korea announced on July 8 that the Ministry of Food and Drug Safety (MFDS) expanded Keytruda’s indication to muscle-invasive bladder cancer (MIBC) and platinum-resistant ovarian cancer.

First, Keytruda was approved as neoadjuvant therapy in combination with enfortumab vedotin prior to surgery, followed by adjuvant therapy after radical cystectomy, for patients with muscle-invasive bladder cancer who are ineligible for cisplatin-containing chemotherapy.

The drug also received approval, with or without bevacizumab, in combination with paclitaxel for patients with PD-L1-positive (CPS ≥1), platinum-resistant epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer who have previously received one or two lines of systemic therapy.

According to data released by the Korea Central Cancer Registry (KCCR) in 2026, bladder cancer predominantly affects older adults, with more than half of patients aged 70 years or older.

Among these patients, muscle-invasive bladder cancer is particularly aggressive, with nearly half eventually developing metastatic disease. Once distant metastasis occurs, the five-year relative survival rate falls to 13.2%, compared with 86.3% for localized disease.

Although cisplatin-based chemotherapy before radical cystectomy remains the  recommended standard of care, many elderly patients and those with impaired renal function are not eligible for the therapy, creating a substantial unmet need for new perioperative treatment strategies.

Keytruda demonstrated clinical benefit in this population when administered as perioperative immunotherapy before and after radical cystectomy.

The approval was based on the Phase III KEYNOTE-905 study, in which patients received neoadjuvant Keytruda plus enfortumab vedotin, underwent radical cystectomy, and then received adjuvant treatment with the same combination. After a median follow-up of 25.6 months, the regimen demonstrated statistically significant improvements in event-free survival (EFS), overall survival (OS), and pathological complete response (pCR) compared with the control group.

The combination reduced the risk of an event by 60% in the EFS analysis and lowered the risk of death by 50% in the OS analysis compared with the control arm. It also achieved a 48.3 percentage-point higher pathological complete response rate than the control arm.

KEYNOTE-B96 expands Keytruda as a treatment option in platinum-resistant ovarian cancer

Ovarian cancer remains an aggressive disease for which neither a definitive cause nor an effective screening method has been established. Even after appropriate first-line chemotherapy, approximately 70% to 80% of patients experience relapse.

Platinum-based chemotherapy is the standard first-line treatment. However, approximately 25% of patients are platinum-refractory, showing little or no response to platinum-based chemotherapy from the outset. Even patients who initially respond often experience recurrence and eventually develop platinum-resistant disease. Until now, treatment for these platinum-resistant patients has largely consisted of non-platinum chemotherapy, with or without bevacizumab, but these regimens have not demonstrated a meaningful reduction in mortality.

Keytruda demonstrated efficacy in the Phase III KEYNOTE-B96 trial involving patients with PD-L1-positive (CPS ≥1), platinum-resistant recurrent ovarian cancer (n=643) who had previously received one or two lines of systemic therapy.

Participants were randomized 1:1 to receive either Keytruda or placebo, in combination with paclitaxel, with or without bevacizumab. In a PFS analysis of patients with CPS ≥1, the Keytruda regimen reduced the risk of disease progression or death by 28%. The regimen also reduced the risk of death by 24% in the OS analysis, demonstrating a statistically significant benefit. Median OS was 18.2 months.

Heesung Lee, Oncology Business Unit Director at MSD Korea, said, “This indication expansion is particularly meaningful in that it provides new treatment options for patients with platinum-resistant ovarian cancer and muscle-invasive bladder cancer, two areas with significant unmet medical needs. We will continue working to expand treatment possibilities for even more patients through Keytruda."

With these approvals, Keytruda now holds 5 approved indications in bladder cancer and 2 in ovarian cancer, bringing its total to 37 approved indications across 18 different cancer types in South Korea.