Drug Interaction Report

MONITOR: The risk of peripheral neuropathy may be increased during concurrent use of two or more agents that are associated with this adverse effect. Patient risk factors include diabetes and age older than 60 years. In some cases, the neuropathy may progress or become irreversible despite discontinuation of the medications.

MANAGEMENT: Caution is advised during concomitant use of agents with neurotoxic effects. Patients should be monitored closely for symptoms of neuropathy such as burning, tingling, pain, or numbness in the hands and feet. Since the development of peripheral neuropathy may be dose-related for many drugs, the recommended dosages should generally not be exceeded. Consideration should be given to dosage reduction or immediate discontinuation of these medications in patients who develop peripheral neuropathy to limit further damage. If feasible, therapy should generally be reinstituted only after resolution of neuropathy symptoms or return of symptoms to baseline status. In some cases, permanent dosage reductions may be required.

MONITOR: Although immune checkpoint inhibitors (ICI) such as programmed cell death-1 (PD-1), programmed death ligand-1 inhibitors (PD-L1), and anti-CTLA-4 monoclonal antibodies may be indicated for use in combination in with other immunosuppressive agents, their pharmacodynamic effects and efficacy may be affected by corticosteroids and immunosuppressants. The mechanism of this interaction is related to the immunosuppressive effects of corticosteroids and other immunosuppressants, particularly their inhibition of T-cell activation, which may reduce the efficacy of immune checkpoint inhibitors that rely on a strong immune response to target tumor cells. Additionally, immune-related adverse events (irAEs) from ICIs may indicate a stronger immune response and improved tumor outcomes and treating them with immunosuppressive agents could therefore reduce immune activity and the efficacy of ICIs. For instance, data from the Dutch Melanoma Treatment Registry (DTMR) showed that patients with advanced melanoma who experienced severe ICI toxicity had a longer median overall survival (OS) (23 months vs. 15 months), but those needing anti-TNF therapy for steroid-refractory toxicity had worse outcomes (17 months vs. 27 months with steroids alone). In a study of patients with advanced NSCLC (n=640), oral or intravenous corticosteroid use (>/= 10 mg prednisone equivalent per day) at the time of or within 30 days of starting PD-1/PD-L1 blockade with either pembrolizumab, nivolumab, atezolizumab, or durvalumab (n=90) was associated with decreased response and overall poorer outcomes, compared to those who received and discontinued corticosteroid treatment prior to commencing PD-1/PD-L1 therapy. Further, an international multicenter cohort study in melanoma patients who developed irAEs with ICI therapy found that higher peak doses of corticosteroids, but not cumulative doses, were associated with worse survival, though the impact of second-line immunosuppressants remains unclear. A prospective observational study using data from a German multicenter skin cancer registry (ADOREG) evaluated patients with unresectable advanced melanoma who received immunosuppressive therapy (IST) (e.g., methylprednisolone, prednisolone, dexamethasone, infliximab, interferon, methotrexate) within 60 days before or within 30 days after the start of an ICI. The initiation of IST before, but not after the start of ICI, was associated with worse progression free survival in patients without brain metastasis, and worse OS in patients with brain metastasis. However, based on available literature, it is difficult to determine whether these effects are due to corticosteroid and/or immunosuppressant use or if they reflect subgroups of patients in studies with poorer prognoses.

MANAGEMENT: Caution and closer monitoring for reduced efficacy of immune checkpoint inhibitors (ICI) is advised if corticosteroids and/or other immunosuppressants are used concurrently. Based on available literature, the use of immunosuppressants and/or systemic corticosteroids (>=10 mg prednisone equivalent/day) should be avoided at the time of, or within 30 to 60 days of starting therapy with an ICI if clinically possible. Corticosteroids and/or immunosuppressants can generally be safely used for the treatment of immune-mediated reactions after starting an ICI. Some manufacturers advise that corticosteroids may be used as premedication when the ICI is used in combination with chemotherapy, as antiemetic prophylaxis, and/or to alleviate chemotherapy-related adverse effects. Individual product labeling for the ICI in question should be consulted for specific recommendations.

MONITOR: Although immune checkpoint inhibitors (ICI) such as programmed cell death-1 (PD-1), programmed death ligand-1 inhibitors (PD-L1), and anti-CTLA-4 monoclonal antibodies may be indicated for use in combination in with other immunosuppressive agents, their pharmacodynamic effects and efficacy may be affected by corticosteroids and immunosuppressants. The mechanism of this interaction is related to the immunosuppressive effects of corticosteroids and other immunosuppressants, particularly their inhibition of T-cell activation, which may reduce the efficacy of immune checkpoint inhibitors that rely on a strong immune response to target tumor cells. Additionally, immune-related adverse events (irAEs) from ICIs may indicate a stronger immune response and improved tumor outcomes and treating them with immunosuppressive agents could therefore reduce immune activity and the efficacy of ICIs. For instance, data from the Dutch Melanoma Treatment Registry (DTMR) showed that patients with advanced melanoma who experienced severe ICI toxicity had a longer median overall survival (OS) (23 months vs. 15 months), but those needing anti-TNF therapy for steroid-refractory toxicity had worse outcomes (17 months vs. 27 months with steroids alone). In a study of patients with advanced NSCLC (n=640), oral or intravenous corticosteroid use (>/= 10 mg prednisone equivalent per day) at the time of or within 30 days of starting PD-1/PD-L1 blockade with either pembrolizumab, nivolumab, atezolizumab, or durvalumab (n=90) was associated with decreased response and overall poorer outcomes, compared to those who received and discontinued corticosteroid treatment prior to commencing PD-1/PD-L1 therapy. Further, an international multicenter cohort study in melanoma patients who developed irAEs with ICI therapy found that higher peak doses of corticosteroids, but not cumulative doses, were associated with worse survival, though the impact of second-line immunosuppressants remains unclear. A prospective observational study using data from a German multicenter skin cancer registry (ADOREG) evaluated patients with unresectable advanced melanoma who received immunosuppressive therapy (IST) (e.g., methylprednisolone, prednisolone, dexamethasone, infliximab, interferon, methotrexate) within 60 days before or within 30 days after the start of an ICI. The initiation of IST before, but not after the start of ICI, was associated with worse progression free survival in patients without brain metastasis, and worse OS in patients with brain metastasis. However, based on available literature, it is difficult to determine whether these effects are due to corticosteroid and/or immunosuppressant use or if they reflect subgroups of patients in studies with poorer prognoses.

MANAGEMENT: Caution and closer monitoring for reduced efficacy of immune checkpoint inhibitors (ICI) is advised if corticosteroids and/or other immunosuppressants are used concurrently. Based on available literature, the use of immunosuppressants and/or systemic corticosteroids (>=10 mg prednisone equivalent/day) should be avoided at the time of, or within 30 to 60 days of starting therapy with an ICI if clinically possible. Corticosteroids and/or immunosuppressants can generally be safely used for the treatment of immune-mediated reactions after starting an ICI. Some manufacturers advise that corticosteroids may be used as premedication when the ICI is used in combination with chemotherapy, as antiemetic prophylaxis, and/or to alleviate chemotherapy-related adverse effects. Individual product labeling for the ICI in question should be consulted for specific recommendations.

MONITOR: Coadministration with inhibitors of CYP450 3A4, such as grapefruit juice, may increase the plasma concentrations of paclitaxel, which is a substrate of the isoenzyme. Current data suggest that consumption of large quantities of grapefruit juice inhibit both intestinal and hepatic CYP450 3A4 due to certain compounds present in grapefruit. Specific data for paclitaxel are lacking; however, in a case report of a 52-year-old woman with esophageal squamous cell carcinoma receiving a twice weekly chemotherapy regimen including intravenous docetaxel (40 mg/m2) reported that docetaxel systemic exposure (AUC) increased by 65% compared with the AUC target of 1.96 mg*h/L and clearance decreased by 63%, with a 71% reduction in the patient's neutrophil count. In the absence of other CYP450 3A4 inhibitors, these effects were attributed to daily consumption of 250 mL of grapefruit juice, which the patient had been consuming for at least 3 months. Two weeks after the patient ceased the grapefruit juice, the docetaxel AUC was closer to the target value and the neutrophil count reduction was less than 35%. In addition, in a pharmacokinetic study consisting of 7 cancer patients, mean dose-normalized docetaxel AUC increased by 2.2-fold and clearance decreased by 49% when intravenous docetaxel was given at a reduced dosage of 10 mg/m2 in combination with the potent CYP450 3A4 inhibitor ketoconazole (200 mg orally once daily for 3 days) compared to docetaxel administered alone at 100 mg/m2.

MANAGEMENT: Caution is recommended if paclitaxel is to be used in combination with grapefruit and grapefruit juice. Patients should be closely monitored for the development of paclitaxel toxicity, including diarrhea, mucositis, myelosuppression, and peripheral neuropathy and dose adjustment considered per local treatment protocols.

The recommended maximum number of medicines in the 'cell cycle non-phase specific antineoplastics' category to be taken concurrently is usually two. Your list includes three medicines belonging to the 'cell cycle non-phase specific antineoplastics' category:

• Carboplatin Novaplus (carboplatin)
• Keytruda (pembrolizumab)
• paclitaxel

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.