Welireg Side Effects Center

SIDE EFFECTS

The following clinically significant adverse reactions are discussed elsewhere in the labeling:

• Anemia [see WARNINGS AND PRECAUTIONS]
• Hypoxia [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety of WELIREG was evaluated in an open-label clinical trial (Study 004) in 61 patients with VHL disease who had at least one measurable solid tumor localized to the kidney [see Clinical Studies]. Patients received WELIREG 120 mg orally once daily. The median duration of exposure to WELIREG was 68 weeks (range: 8.4 to 104.7 weeks).

Serious adverse reactions occurred in 15% of patients who received WELIREG, including anemia, hypoxia, anaphylaxis reaction, retinal detachment, and central retinal vein occlusion (1 patient each).

Permanent discontinuation of WELIREG due to adverse reactions occurred in 3.3% of patients. Adverse reactions which resulted in permanent discontinuation of WELIREG were dizziness and opioid overdose (1.6% each).

Dosage interruptions of WELIREG due to an adverse reaction occurred in 39% of patients. Adverse reactions which required dosage interruption in >2% of patients were fatigue, decreased hemoglobin, anemia, nausea, abdominal pain, headache, and influenza-like illness.

Dose reductions of WELIREG due to an adverse reaction occurred in 13% of patients. The most frequently reported adverse reaction which required dose reduction was fatigue (7%).

The most common (≥25%) adverse reactions, including laboratory abnormalities, that occurred in patients who received WELIREG were decreased hemoglobin, anemia, fatigue, increased creatinine, headache, dizziness, increased glucose, and nausea.

Table 2 summarizes the adverse reactions reported in patients treated with WELIREG in Study 004.

Table 2: Adverse Reactions Occurring in ≥10% of Patients Who Received WELIREG in Study 004

Table 3 summarizes the laboratory abnormalities in Study 004.

Table 3: Select Laboratory Abnormalities (>10%) That Worsened from Baseline in Patients Who Received WELIREG in Study 004

Other Clinical Trials Experience

In Study 001 (NCT02974738), a clinical trial in patients with advanced solid tumors (n=58) treated at the recommended dose in which the median age of enrollment was 62.5 years (range 39-75) and the median number of prior therapies for cancer was 3 (range 1-9), the following additional adverse reactions have been reported following administration of WELIREG at the recommended dosage: edema, cough, musculoskeletal pain, vomiting, diarrhea, and dehydration.

DRUG INTERACTIONS

Effects Of Other Drugs On WELIREG

UGT2B17 Or CYP2C19 Inhibitors

Coadministration of WELIREG with inhibitors of UGT2B17 or CYP2C19 increases plasma exposure of belzutifan [see CLINICAL PHARMACOLOGY], which may increase the incidence and severity of adverse reactions of WELIREG. Monitor for anemia and hypoxia and reduce the dosage of WELIREG as recommended [see DOSAGE AND ADMINISTRATION, WARNINGS AND PRECAUTIONS, ADVERSE REACTIONS].

Effect Of WELIREG On Other Drugs

Sensitive CYP3A4 Substrates

Coadministration of WELIREG with CYP3A4 substrates decreases concentrations of CYP3A substrates [see CLINICAL PHARMACOLOGY], which may reduce the efficacy of these substrates. The magnitude of this decrease may be more pronounced in patients who are dual UGT2B17 and CYP2C19 poor metabolizers [see CLINICAL PHARMACOLOGY]. Avoid coadministration of WELIREG with sensitive CYP3A4 substrates, for which minimal decrease in concentration may lead to therapeutic failures of the substrate. If coadministration cannot be avoided, increase the sensitive CYP3A4 substrate dosage in accordance with its Prescribing Information.

Hormonal Contraceptives

Coadministration of WELIREG with hormonal contraceptives may lead to contraceptive failure or an increase in breakthrough bleeding [see CLINICAL PHARMACOLOGY, Use In Specific Populations].

Read the entire FDA prescribing information for Welireg (Belzutifan Tablets)