Overview
Keytruda Qlex is approved by the U.S. Food and Drug Administration (FDA) for the treatment of certain forms of triple-negative breast cancer (TNBC). It is approved for adults with high-risk early-stage TNBC in combination with chemotherapy as neoadjuvant (before surgery) treatment, followed by Keytruda Qlex alone as adjuvant (after surgery) treatment.

 It is also approved in combination with chemotherapy for adults with locally recurrent unresectable or metastatic TNBC whose tumors express PD-L1 (a protein that helps cancer evade immune detection), as determined by an FDA-approved test. 

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 breast 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 chemotherapy, depending on the cancer stage and whether the tumor expresses PD-L1. 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, 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, and inflammation of mucous membranes.

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