Overview
Keytruda Qlex is approved by the U.S. Food and Drug Administration (FDA) for the treatment of certain types of endometrial cancer. It is approved in combination with carboplatin and paclitaxel, followed by Keytruda Qlex alone, for adults with primary advanced or recurrent endometrial carcinoma.

It is also approved in combination with lenvatinib for adults with advanced endometrial carcinoma that is mismatch repair proficient (pMMR) or not microsatellite instability-high (MSI-H), whose cancer has progressed following prior systemic therapy and who are not candidates for curative surgery or radiation.

Additionally, it is approved as a single agent for adults with advanced endometrial carcinoma that is MSI-H or mismatch repair deficient (dMMR) following prior systemic therapy in any setting when curative surgery or radiation is not an option. 

Keytruda Qlex is also known by its drug name, pembrolizumab and berahyaluronidase alfa-pmph.

Keytruda Qlex is a type of immunotherapy. It works by blocking the PD-1 protein on immune cells, which helps the immune system recognize and attack endometrial cancer cells. Berahyaluronidase alfa helps the medication absorb more efficiently when injected under the skin.

How do I take it?
Prescribing information states that Keytruda Qlex is given as a subcutaneous (under the skin) injection into the abdomen or thigh by a healthcare provider. It is typically administered once every three or six weeks, depending on the dosing schedule. Keytruda Qlex may be used alone or in combination with other drugs such as carboplatin, paclitaxel, or lenvatinib, depending on the cancer’s genetic characteristics and treatment history. It should be taken exactly as prescribed by a healthcare provider.

Side effects
Common side effects of Keytruda Qlex include fatigue, nausea, musculoskeletal pain (pain in muscles, bones, or joints), rash, diarrhea, decreased appetite, cough, shortness of breath, constipation, abdominal pain, fever, itching, and hypothyroidism (low thyroid hormone levels).

When used in combination with chemotherapy (e.g., carboplatin or paclitaxel), side effects may also include vomiting, hair loss, peripheral neuropathy (nerve damage causing pain or numbness), mouth sores, weight loss, joint and muscle pain, insomnia, hand-foot syndrome (skin reaction on palms and soles), urinary tract infections, protein in the urine, high blood pressure, liver damage, and bleeding events.

When used in combination with lenvatinib, side effects may also include protein in the urine, high blood pressure, liver damage, bleeding events, weight loss, nausea, vomiting, and urinary tract infections.

Rare but serious side effects may include immune-mediated reactions such as pneumonitis (lung inflammation), colitis (intestinal inflammation), hepatitis (liver inflammation), endocrinopathies (hormone gland problems), nephritis (kidney inflammation), severe skin reactions, and rejection of transplanted organs. Severe allergic reactions and complications following stem cell transplant may also occur. The drug may cause harm to an unborn baby and is not recommended during pregnancy.

For more information about this treatment, visit:

Keytruda Qlex (Pembrolizumab and Berahyaluronidase Alfa-Pmph) Injection, for Subcutaneous Use — Merck Sharp & Dohme