FDA Approves KEYTRUDA (pembrolizumab) Plus LENVIMA (lenvatinib) Combination for Patients With Certain Types of Advanced Endometrial Carcinoma

Merck, known as MSD outside the United States and Canada, and Eisai Inc. announced that the U.S. Food and Drug Administration (FDA) has approved the combination of KEYTRUDA, Merck’s anti-PD-1 therapy, plus LENVIMA, the orally available multiple receptor tyrosine kinase inhibitor discovered by Eisai, for the treatment of patients with advanced endometrial carcinoma that is not microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR), who have disease progression following prior systemic therapy in any setting and are not candidates for curative surgery or radiation. The approval for this population is based on results from the pivotal Phase 3 KEYNOTE-775/Study 309 trial, in which KEYTRUDA plus LENVIMA demonstrated statistically significant improvements in overall survival (OS), reducing the risk of death by 32% (HR=0.68 [95% CI, 0.56-0.84]; p=0.0001), and progression-free survival (PFS), reducing the risk of disease progression or death by 40% (HR=0.60 [95% CI, 0.50-0.72]; p<0.0001), versus chemotherapy (investigator’s choice of doxorubicin or paclitaxel). KEYTRUDA plus LENVIMA also demonstrated a statistically significant improvement in objective response rate (ORR), with an ORR of 30% (95% CI, 26-36) versus 15% (95% CI, 12-19) for patients who received investigator’s choice of doxorubicin or paclitaxel, in addition to a complete response rate of 5% for KEYTRUDA plus LENVIMA versus 3% for doxorubicin or paclitaxel and a partial response rate of 25% versus 13%, respectively.

Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or tissue and can affect more than one body system simultaneously. Immune-mediated adverse reactions can occur at any time during or after treatment with KEYTRUDA, including pneumonitis, colitis, hepatitis, endocrinopathies, nephritis, dermatologic reactions, solid organ transplant rejection, and complications of allogeneic hematopoietic stem cell transplantation. Important immune-mediated adverse reactions listed here may not include all possible severe and fatal immune-mediated adverse reactions. Early identification and management of immune-mediated adverse reactions are essential to ensure safe use of KEYTRUDA. Based on the severity of the adverse reaction, KEYTRUDA should be withheld or permanently discontinued and corticosteroids administered if appropriate. KEYTRUDA can also cause severe or life-threatening infusion-related reactions. Based on its mechanism of action, KEYTRUDA can cause fetal harm when administered to a pregnant woman. For more information, see “Selected Important Safety Information” below.

Adverse reactions, some of which can be serious or fatal, may occur with LENVIMA, including hypertension, cardiac dysfunction, arterial thromboembolic events, hepatotoxicity, renal failure or impairment, proteinuria, diarrhea, fistula formation and gastrointestinal perforation, QT interval prolongation, hypocalcemia, reversible posterior leukoencephalopathy syndrome, hemorrhagic events, impairment of thyroid stimulating hormone suppression/thyroid dysfunction, impaired wound healing and osteonecrosis of the jaw. Based on the type and/or severity of the adverse reaction, LENVIMA may be interrupted, reduced and/or discontinued. Based on its mechanism of action and data from animal reproduction studies, LENVIMA can cause fetal harm when administered to a pregnant woman. Females of reproductive potential should be advised to use effective contraception. For more information, see “Selected Safety Information” below.

“With a five-year survival rate of just 17%, women with advanced endometrial cancer who are not candidates for curative therapy, particularly those with disease progression following prior systemic therapy, have limited treatment options,” said Dr. Vicky Makker, principal investigator and medical oncologist, Memorial Sloan Kettering Cancer Center. “This approval is an important step forward in helping patients fight this difficult-to-treat malignancy, as physicians can now provide an option that may improve survival outcomes.”

“When compared to the chemotherapies used in this trial, this combination treatment regimen was proven to extend the lives of certain patients diagnosed with previously treated, advanced endometrial cancer,” said Dr. Gregory Lubiniecki, Vice President, Oncology Clinical Research, Merck Research Laboratories. “Based on Phase 3 data, today’s approval acts as the confirmatory trial to our previous accelerated approval of KEYTRUDA plus LENVIMA in patients with certain types of advanced endometrial cancer and reinforces the impact of our joint research with Eisai in exploring the potential of this combination to treat more patients with challenging types of cancer.”

“This FDA approval of KEYTRUDA plus LENVIMA for the treatment of patients with certain types of advanced endometrial cancer is an important step forward towards helping this patient community that has had limited treatment options,” said Dr. Takashi Owa, Chief Medicine Creation Officer and Chief Discovery Officer, Oncology Business Group at Eisai. “This marks a culmination of our relentless pursuit to address unmet needs of people with cancer, and we owe our deepest gratitude to those who participated in our KEYNOTE-775/Study 309 trial, their families and clinicians, and to our employees, whose collective commitment made this meaningful milestone possible.”

KEYTRUDA plus LENVIMA was previously approved under the FDA’s accelerated approval process, as well as under the agency’s Real-Time Oncology Review pilot program and its Project Orbis initiative, for the treatment of patients with advanced endometrial carcinoma that is not MSI-H or dMMR, who have disease progression following prior systemic therapy and are not candidates for curative surgery or radiation based on data from the KEYNOTE-146/Study 111 trial. In accordance with accelerated approval regulations, continued approval was contingent upon verification and description of clinical benefit; these accelerated approval requirements have been fulfilled with the data from KEYNOTE-775/Study 309.

Data Supporting the Approval

The approvalwas based on data from KEYNOTE-775/Study 309 (ClinicalTrials.gov, NCT03517449), a multicenter, open-label, randomized, active-controlled trial that enrolled 827 patients with advanced endometrial carcinoma who had been previously treated with at least one prior platinum-based chemotherapy regimen in any setting, including in the neoadjuvant and adjuvant settings. Patients with endometrial sarcoma, including carcinosarcoma, or patients who had active autoimmune disease or a medical condition that required immunosuppression were ineligible. Patients with endometrial carcinoma that were not MSI-H or dMMR were stratified by ECOG performance status, geographic region, and history of pelvic radiation. Patients were randomized (1:1) to one of the following treatment arms:

• KEYTRUDA (200 mg intravenously [IV] every three weeks) in combination with LENVIMA (20 mg orally once daily); or

• Investigator’s choice, consisting of either doxorubicin (60 mg/m² every three weeks) or paclitaxel (80 mg/m² given weekly, three weeks on/one week off).

Treatment with KEYTRUDA plus LENVIMA continued until Response Evaluation Criteria in Solid Tumors (RECIST) v1.1-defined progression of disease as verified by blinded independent central review (BICR), unacceptable toxicity, or for KEYTRUDA, a maximum of 24 months. Treatment was permitted beyond RECIST v1.1-defined disease progression if the treating investigator considered the patient to be deriving clinical benefit and the treatment was tolerated. Assessment of tumor status was performed every eight weeks. The major efficacy outcome measures were OS and PFS as assessed by BICR according to RECIST v1.1, modified to follow a maximum of 10 target lesions and a maximum of five target lesions per organ. Additional efficacy outcome measures included ORR and DOR, as assessed by BICR.

Among the 697 not dMMR patients, 346 patients were randomized to KEYTRUDA plus LENVIMA, and 351 patients were randomized to investigator’s choice of doxorubicin (n=254) or paclitaxel (n=97). The not dMMR population characteristics were: median age of 65 years (range: 30 to 86), 52% age 65 or older; 62% White, 22% Asian, and 3% Black; 60% ECOG PS of 0, and 40% ECOG PS of 1. The histologic subtypes were endometrioid carcinoma (55%), serous (30%), clear cell carcinoma (7%), mixed (4%), and other (3%). All 697 of these patients received prior systemic therapy for endometrial carcinoma: 67% had one, 30% had two, and 3% had three or more prior systemic therapies. Thirty-seven percent of patients received only prior neoadjuvant or adjuvant therapy.

Efficacy results for the not MSI-H or dMMR patients are summarized in the table below:

For patients with not MSI-H or dMMR status, the median duration of study treatment was 7.2 months (range: 1 day to 26.8 months) and the median duration of exposure to KEYTRUDA was 6.8 months (range: 1 day to 25.8 months). The median duration of exposure to LENVIMA was 6.7 months (range: 1 day to 26.8 months).

Fatal adverse reactions among these patients occurred in 4.7% of those treated with KEYTRUDA plus LENVIMA, including two cases of pneumonia, and one of the following: acute kidney injury, acute myocardial infarction, colitis, decreased appetite, intestinal perforation, lower gastrointestinal hemorrhage, malignant gastrointestinal obstruction, multiple organ dysfunction syndrome, myelodysplastic syndrome, pulmonary embolism, and right ventricular dysfunction.

Serious adverse reactions occurred in 50% of these patients receiving KEYTRUDA plus LENVIMA. Serious adverse reactions (≥3%) were hypertension (4.4%) and urinary tract infections (3.2%).

Discontinuation of KEYTRUDA due to an adverse reaction (Grades 1-4) occurred in 15% of these patients. Discontinuation of LENVIMA due to an adverse reaction (Grades 1-4) occurred in 26% of these patients. The most common adverse reaction leading to discontinuation of KEYTRUDA (≥1%) was increased alanine aminotransferase (ALT) (1.2%). The most common adverse reactions leading to discontinuation of LENVIMA (≥1%) were hypertension (2.0%), asthenia (1.8%), diarrhea (1.2%), decreased appetite (1.2%), proteinuria (1.2%), and vomiting (1.2%).

Dose interruptions of KEYTRUDA due to an adverse reaction occurred in 48% of these patients. Dose interruptions of LENVIMA due to an adverse reaction occurred in 58% of these patients. The most common adverse reactions leading to interruption of KEYTRUDA (≥3%) were diarrhea (8%), increased ALT (4.4%), increased AST (3.8%), and hypertension (3.5%). The most common adverse reactions leading to interruption of LENVIMA (≥2%) were hypertension (11%), diarrhea (11%), proteinuria (6%), decreased appetite (5%), vomiting (5%), increased ALT (3.5%), fatigue (3.5%), nausea (3.5%), abdominal pain (2.9%), decreased weight (2.6%), urinary tract infection (2.6%), increased aspartate aminotransferase (AST) (2.3%), asthenia (2.3%), and palmar-plantar erythrodysesthesia (2%).

Dose reductions of LENVIMA due to adverse events occurred in 67% of patients. The most common (≥5%) adverse reactions resulting in dose reduction of LENVIMA were hypertension (18%), diarrhea (11%), palmar-plantar erythrodysesthesia syndrome (9%), proteinuria (7%), fatigue (7%), decreased appetite (6%), asthenia (5%), and decreased weight (5%).

The most common adverse reactions of these patients(all grades ≥20%) for KEYTRUDA plus LENVIMA were hypothyroidism (67%), hypertension (67%), fatigue (58%), diarrhea (55%), musculoskeletal disorders (53%), nausea (49%), decreased appetite (44%), vomiting (37%), stomatitis (35%), decreased weight (34%), abdominal pain (34%), urinary tract infection (31%), proteinuria (29%), constipation (27%), headache (26%), hemorrhagic events (25%), palmar-plantar erythrodysesthesia (23%), dysphonia (22%), and rash (20%).