Retifanlimab interacts in the following cases:
The use of systemic corticosteroids or immunosuppressants before starting retifanlimab, except for physiological doses of systemic corticosteroids (≤10 mg/day prednisone or equivalent), should be avoided because of their potential interference with the pharmacodynamic activity and efficacy of retifanlimab. However, systemic corticosteroids or other immunosuppressants can be used after starting retifanlimab to treat immune-related adverse reactions.
There is insufficient data in patients with severe renal impairment (creatinine clearance <30 mL/min) and no data for patients with end-stage renal disease and therefore no dosing recommendation can be mad.
There are insufficient data in patients with moderate hepatic impairment and no data in patients with severe hepatic impairment and therefore no dosing recommendations can be made.
Fatal and other serious complications can occur in patients who receive allogeneic haematopoietic stem cell transplantation (HSCT) before or after being treated with a PD-1/PD-L1–blocking antibody. Transplant-related complications include hyperacute graft-versus-host disease (GvHD), acute GvHD, chronic GvHD, hepatic veno-occlusive disease after reduced intensity conditioning and steroid-requiring febrile syndrome (without an identified infectious cause). These complications may occur despite intervening therapy between PD-1/PD-L1 blockade and allogeneic HSCT. Patients should be closely followed for evidence of transplant-related complications and prompt intervention may be required. Consider the benefit versus risks of treatment with a PD-1/PD-L1–blocking antibody prior to or after an allogeneic HSCT.
Solid organ transplant rejection has been reported in the post-marketing setting in patients treated with PD-1 inhibitors. Treatment with retifanlimab may increase the risk of rejection in solid organ transplant recipients. The benefit of treatment with retifanlimab versus the risk of possible organ rejection should be considered in these patients.
There are no data from the use of retifanlimab in pregnant women. Animal reproduction studies have not been conducted with retifanlimab. Animal studies have demonstrated that inhibition of the PD-1/PD-L1 pathway can lead to increased risk of immune-mediated rejection of the developing foetus resulting in foetal death. Therefore, based on its mechanism of action, retifanlimab can cause foetal harm when administered to a pregnant woman. Human IgG4 immunoglobulins are known to cross the placenta; therefore, retifanlimab has the potential to be transmitted from the mother to the developing foetus. Retifanlimab is not recommended during pregnancy and in women of childbearing potential not using effective contraception.
It is unknown whether retifanlimab is excreted in human milk. There is insufficient information on the excretion of retifanlimab in animal milk.
Human IgGs are known to be excreted in breast milk during the first few days after birth; which decreases to low concentrations soon afterwards; consequently, a risk to the breast-fed infant cannot be excluded during this short period. For this specific period, a decision should be made whether to discontinue/abstain from retifanlimab therapy, taking into account the benefit of breast-feeding to the child and the benefit of therapy to the woman. Afterwards, retifanlimab could be used during breast-feeding if clinically needed.
Women of childbearing potential should use effective contraception during treatment with retifanlimab and for at least 4 months after the last dose of retifanlimab.
No clinical data are available on the possible effects of retifanlimab on fertility. Animal reproduction studies to evaluate the effect of retifanlimab on fertility have not been conducted.
Retifanlimab has minor influence on the ability to drive and use machines. Because of potential adverse reactions such as fatigue, patients should be advised to use caution when driving or operating machinery until they are certain that retifanlimab does not adversely affect them.
Immune-related adverse reactions occurred with retifanlimab. Most of these, including severe reactions, resolved following initiation of appropriate medical therapy or withdrawal of retifanlimab (see "Description of selected adverse reactions" below).
The safety of retifanlimab as monotherapy has been evaluated in 452 patients with advanced solid malignancies who received the recommended 500 mg every 4 weeks dose, including 107 patients with metastatic or recurrent locally advanced MCC. Median duration of treatment was 5.4 months (range, 1 day – 27 months). The most common adverse reactions were fatigue (35.4%), rash (18.8%), diarrhoea (18.6%), anaemia (16.2%), pruritus (15.9%), arthralgia (13.3%), constipation (13.3%), nausea (13.3%), pyrexia (13.1%) and decreased appetite (12.6%). Adverse reactions were serious in 11.7% of patients; most serious adverse reactions were immune-related adverse reactions. Retifanlimab was permanently discontinued due to adverse reactions in 8% of patients; most of them were immune-related events.
The safety of retifanlimab in combination with carboplatin and paclitaxel has been evaluated in 154 patients with metastatic or with inoperable locally recurrent SCAC. Median duration of retifanlimab treatment was 7.4 months (range, 1 day – 14.6 months). The most common adverse reactions were neutropenia (70.1%), pruritus (24%), rash (23.4%), lymphopenia (14.3%), hypothyroidism (14.3%), and alanine aminotransferase increased (10.4%). Adverse reactions were serious in 13.6% of patients; most serious adverse reactions were immune-related adverse reactions. Retifanlimab was permanently discontinued due to adverse reactions in 5.8% of patients; most of them were immune-related events.
Adverse reactions reported in the pooled dataset for patients treated with retifanlimab monotherapy (N=452) and in combination with carboplatin and paclitaxel (N=154) are presented in the table below.
These reactions are presented by system organ class and by frequency. Frequencies are defined as: very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1 000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10,000); and not known (cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in order of decreasing incidence.
Adverse reactions in patients treated with retifanlimab:
| Retifanlimab monotherapy (N=452) | Retifanlimab in combination with carboplatin and paclitaxel (N=154) | |||
| System organ class | Frequency of all grades | Frequency of grades 3-4 | Frequency of all grades | Frequency of grades 3-4 |
| Blood and lymphatic system disorders | Very common Anaemiaa | Common Anaemiaa | Very common Lymphopeniab Neutropeniac | Very common Neutropeniac Common Lymphopeniab |
| Endocrine disorders | Common Hypothyroidism, Hyperthyroidism Uncommon Adrenal insufficiency Thyroiditisd Hypophysitis Type 1 diabetes mellituse | Uncommon Adrenal insufficiency Hypophysitis Type 1 diabetes mellituse | Very common Hypothyroidism Common Adrenal insufficiency Hyperthyroidism Hypophysitis Hyperglycaemia Uncommon Autoimmune thyroiditis Secondary adrenocortical insufficiency | Common Adrenal insufficiency Uncommon Hypothyroidism Hyperthyroidism Secondary adrenocortical insufficiency |
| Metabolism and nutrition disorders | Very common Decreased appetite | Uncommon Decreased appetite | Common Hyponatraemia | Common Hyponatraemia |
| Nervous system disorders | Common Paraesthesia Uncommon Polyneuropathyf Radiculopathy Vocal cord paralysis | Uncommon Polyneuropathyf Radiculopathy | Very common Peripheral sensory neuropathy Common Peripheral motor neuropathy Peripheral sensorimotor neuropathy | Common Peripheral sensorimotor neuropathy |
| Eye disorders | Uncommon Uveitisg Keratitis | Uncommon Uveitisg | ||
| Cardiac disorders | Uncommon Pericarditis Myocarditis | Uncommon Myocarditis | ||
| Respiratory, thoracic and mediastinal disorders | Common Pneumonitish | Uncommon Pneumonitish | ||
| Gastrointestinal disorders | Very common Diarrhoea Nausea Constipation Common Colitisi Uncommon Pancreatitis | Uncommon Diarrhoea Pancreatitis Colitisi | Very common Colitisj Common Stomatitis | Common Colitisj |
| Hepatobiliary disorders | Common Hepatocellular injury Hepatitisk Uncommon Hyperbilirubinaemia Cholangitis | Uncommon Hepatitisk Hepatocellular injury Cholangitis Hyperbilirubinaemia | Common Hepatitisl Uncommon Immune-mediated cholangitis | Common Hepatitisl Uncommon Immune-mediated cholangitis |
| Skin and subcutaneous skin disorders | Very common Rashm Pruritus | Common Rashm | Very common Pruritus Rashn | Common Rashn Uncommon Pruritus |
| Musculoskeletal and connective tissue disorders | Very common Arthralgia Uncommon Arthritis° Myositis Eosinophilic fasciitis Polymyalgia rheumatica | Uncommon Arthralgia Arthritis° Myositis Eosinophilic fasciitis | Common Arthritis | |
| Renal and urinary disorders | Common Acute kidney injury Renal failure Uncommon Tubulointerstitial nephritis | Uncommon Acute kidney injury Tubulointerstitial nephritis | ||
| General disorders and administration site conditions | Very common Fatiguep Pyrexia | Common Fatiguep Uncommon Pyrexia | Very common Asthenia | Common Asthenia |
| Investigations | Common Transaminases increasedq Blood creatinine increased Amylase increased Lipase increased Blood bilirubin increased Blood thyroid stimulating hormone increased Uncommon Blood thyroid stimulating hormone decreased | Common Transaminases increasedq Uncommon Blood bilirubin increased Lipase increased Blood creatinine increased Amylase increased | Very common Alanine aminotransferase increased Common Aspartate aminotransferase increased Lipase increased Blood creatinine increased Amylase increased | Common Alanine aminotransferase increased Aspartate aminotransferase increased Lipase increased Uncommon Blood creatinine increased Amylase increased |
| Injury, poisoning and procedural complications | Common Infusion-related reactionr | Uncommon Infusion-related reactionr | Common Infusion-related reaction | Uncommon Infusion-related reaction |
a Includes anaemia, iron deficiency anaemia, anaemia of malignant disease and anaemia vitamin B12 deficiency.
b Includes lymphopenia and lymphocyte count decreased.
c Includes neutropenia and neutrophil count decreased.
d Includes thyroiditis and autoimmune thyroiditis.
e Includes diabetic ketoacidosis.
f Includes polyneuropathy and demyelinating polyneuropathy.
g Includes uveitis and iritis.
h Includes pneumonitis, interstitial lung disease, organising pneumonia and lung infiltration.
i Includes colitis and immune mediated enterocolitis.
j Includes colitis, immune mediated enterocolitis and immune mediated diarrhoea.
k Includes hepatitis and autoimmune hepatitis.
l Includes hepatitis and immune-mediated hepatitis.
m Includes rash, rash maculo-papular, rash erythematous, rash pruritic, dermatitis, psoriasis, rash macular, rash papular, lichenoid keratosis, rash pustular, dermatitis bullous, palmar-plantar erythrodyseasthesia syndrome, toxic epidermal necrolysis and toxic skin eruption.
n Includes rash, rash erythematous, rash maculo-papular and rash pruritic.
° Includes arthritis and polyarthritis.
p Includes asthenia and fatigue.
q Includes transaminases increased, alanine aminotransferase increased and aspartate aminotransferase increased.
r Includes drug hypersensitivity and infusion related reaction.
The selected adverse reactions described below are based on the safety of retifanlimab monotherapy in a pooled safety population of 452 patients with advanced solid malignancies, including patients with metastatic or recurrent locally advanced MCC and on the safety of retifanlimab in combination with carboplatin and paclitaxel in 154 patients with metastatic or with inoperable locally recurrent SCAC. The management guidelines for these adverse reactions are described in section 4.2.
Immune-related pneumonitis occurred in 3.1% of patients receiving retifanlimab monotherapy, including 1.3% of patients with Grade 2, 0.9% of patients with Grade 3 and 0.2% of patients with Grade 5. The median time to onset of pneumonitis was 100 days (range, 43 – 673 days). Pneumonitis led to discontinuation of retifanlimab in 0.2% of patients. Among the patients with pneumonitis, 71.4% received systemic corticosteroids. Pneumonitis resolved in 78.6% of patients, with a median time to resolution of 37 days (range, 9 – 104 days).
Immune-related colitis occurred in 2.7% of patients receiving retifanlimab monotherapy, including 1.1% of patients with Grade 2, 0.4% of patients with Grade 3 and 0.2% of patients with Grade 4. The median time to onset of colitis was 165.5 days (range, 11 – 749 days). Colitis led to discontinuation of retifanlimab in 0.9% of patients. Among the patients with colitis, 75% received systemic corticosteroids and 8.3% received another immunosuppressant (infliximab). Colitis resolved in 66.7% of patients, with a median time to resolution of 83.5 days (range, 15 – 675 days).
In patients with SCAC receiving retifanlimab in combination with carboplatin and paclitaxel, immune-related colitis occurred in 10.4% of patients, including 3.2% of patients with Grade 2, 2.6% of patients with Grade 3 and 0.6% of patients with Grade 4. The median time to onset of colitis was 83.5 days (range, 3 – 271 days). Colitis led to discontinuation of retifanlimab in 1.3% of patients. Among the patients with colitis, 93.8% received systemic corticosteroids and 6.3% received another immunosuppressant (infliximab). Colitis resolved in 93.8% of patients, with a median time to resolution of 27 days (range, 1 – 102 days).
Immune-related nephritis occurred in 2% of patients receiving retifanlimab monotherapy, including 0.4% of patients with Grade 2, 1.1% of patients with Grade 3 and 0.4% of patients with Grade 4. The median time to onset of nephritis was 176 days (range, 15 – 515 days). Nephritis led to discontinuation of retifanlimab in 1.1% of patients. Among the patients with nephritis, 66.7% received systemic corticosteroids. Nephritis resolved in 44.4% of patients, with a median time to resolution of 22.5 days (range, 9 – 136 days).
Hypothyroidism occurred in 10.2% of patients receiving retifanlimab monotherapy, including 4.9% of patients with Grade 2. The median time to onset of hypothyroidism was 88 days (range, 1 – 505 days). None of the events led to discontinuation of retifanlimab. Hypothyroidism resolved in 32.6% of patients, with a median time to resolution of 56 days (range, 2 – 224 days).
In patients with SCAC receiving retifanlimab in combination with carboplatin and paclitaxel, hypothyroidism occurred in 14.3% of patients, including 9.1% of patients with Grade 2 and 0.6% of patients with Grade 4. The median time to onset of hypothyroidism was 138.5 days (range, 55 – 390 days). Hypothyroidism led to discontinuation of retifanlimab in 1 patient. Hypothyroidism resolved in 27.3% of patients, with a median time to resolution of 114 days (range, 57 – 212 days).
Hyperthyroidism occurred in 5.8% of patients receiving retifanlimab monotherapy, including 2.7% of patients with Grade 2. The median time to onset of hyperthyroidism was 55.5 days (range, 8 – 575 days). None of the events led to discontinuation of retifanlimab. Hyperthyroidism resolved in 61.5% of patients, with a median time to resolution of 74 days (range, 15 – 295 days).
In patients with SCAC receiving retifanlimab in combination with carboplatin and paclitaxel, hyperthyroidism occurred in 8.4% of patients, including 3.2% of patients with Grade 2 and 0.6% of patients with Grade 3. The median time to onset of hyperthyroidism was 82 days (range, 8 – 278 days). None of the events led to discontinuation of retifanlimab. Hyperthyroidism resolved in 76.9% of patients, with a median time to resolution of 29 days (range, 8 – 130 days).
Hypophysitis occurred in 0.7% of patients receiving retifanlimab monotherapy, including 0.4% of patients with Grade 2 and 0.2% of patients with Grade 3. The median time to onset of hypophysitis was 308 days (range, 266 – 377 days). Hypophysitis led to discontinuation of retifanlimab in 0.2% of patients. Hypophysitis resolved in 33.3% of patients, with a time to resolution of 6 days.
In patients with SCAC receiving retifanlimab in combination with carboplatin and paclitaxel, hypophysitis occurred in 2 patients (1.3%, both Grade 2). The median time to onset of hypophysitis was 192 days (range, 90 – 294 days). Neither of the events led to discontinuation of retifanlimab. Hypophysitis resolved in 1 of the 2 patients, with a time to resolution of 8 days.
Adrenal insufficiency occurred in 0.9% of patients receiving retifanlimab monotherapy, including 0.4% of patients with Grade 2 and 0.4% of patients with Grade 3. The median time to onset of adrenal insufficiency was 220.5 days (range, 146 – 275 days). None of the events led to discontinuation of retifanlimab. Adrenal insufficiency resolved in 25% of patients, with a time to resolution of 12 days.
In patients with SCAC receiving retifanlimab in combination with carboplatin and paclitaxel, adrenal insufficiency occurred in 5.8% of patients, including 1.9% of patients with Grade 2 and 1.9% of patients with Grade 3. The median time to onset of adrenal insufficiency was 197 days (range, 63 – 302 days). One event led to discontinuation of retifanlimab. Adrenal insufficiency resolved in 44.4% of patients, with a time to resolution of 13.5 days.
Type 1 diabetes mellitus presenting as diabetic ketoacidosis (Grade 3) occurred in 0.2% of patients receiving retifanlimab monotherapy. The time to onset of diabetic ketoacidosis was 284 days. The event did not lead to discontinuation of retifanlimab and resolved with a time to resolution of 6 days.
Immune-related hepatitis occurred in 3.5% of patients receiving retifanlimab monotherapy, including 0.9% of patients with Grade 2, 2.4% of patients with Grade 3 and 0.2% of patients with Grade 4. The median time to onset of hepatitis was 70.5 days (range, 8 – 580 days). Hepatitis led to discontinuation of retifanlimab in 1.5% of patients. Among the patients with hepatitis, 81.3% of patients received systemic corticosteroids and 6.3% of patients received another immunosuppressant (mycophenolate mofetil). Hepatitis resolved in 56.3% of patients, with a median time to resolution of 22 days (range, 6 – 104 days).
In patients with SCAC receiving retifanlimab in combination with carboplatin and paclitaxel, immune-related hepatitis occurred in 2 patients (1.3%, both Grade 3). The median time to onset of hepatitis was 195.5 days (range, 140 – 251 days). Hepatitis led to discontinuation of retifanlimab in 1 patient. Both patients with hepatitis received systemic corticosteroids and another immunosuppressant (mycophenolate mofetil). Hepatitis resolved in both patients, with a median time to resolution of 58.5 days (range, 57 – 60 days).
Immune-related skin reactions occurred in 9.5% of patients receiving retifanlimab monotherapy, including 8% of patients with Grade 2, 1.1% of patients with Grade 3 and 0.2% of patients with Grade 4. The median time to onset of skin reactions was 86 days (range, 2 – 589 days). Skin reactions led to discontinuation of retifanlimab in 0.7% of patients. Among the patients with skin reactions, 32.6% of patients received systemic corticosteroids. Skin reactions resolved in 72.1% of patients, with a median time to resolution of 37 days (range, 3 – 470 days).
In patients with SCAC receiving retifanlimab in combination with carboplatin and paclitaxel, immune-related skin reactions occurred in 11.7% of patients, including 9.7% of patients with Grade 2 and 1.9% of patients with Grade 3. The median time to onset of skin reactions was 46.5 days (range, 2 – 443 days). Skin reactions led to discontinuation of retifanlimab in 2 patients. Among the patients with skin reactions, 33.3% of patients received systemic corticosteroids. Skin reactions resolved in 72.2% of patients, with a median time to resolution of 22 days (range, 5 – 385 days).
Infusion-related reactions occurred in 6.2% of patients receiving retifanlimab monotherapy, including 2.2% of patients with Grade 2 and 0.4% of patients with Grade 3. Infusion-related reactions led to discontinuation of retifanlimab in 0.4% patients. In patients with SCAC receiving retifanlimab in combination with carboplatin and paclitaxel, infusion-related reactions occurred in 9.7% of patients, including 1.9% of patients with Grade 3. None of the infusion-related reactions led to discontinuation of retifanlimab.
In patients with SCAC receiving retifanlimab in combination with chemotherapy, the proportion of patients who experienced a shift from baseline to a Grade 3 or 4 laboratory abnormality occurring in >3% of patients was 42.8% for decreased lymphocytes, 52% for decreased neutrophils, 4.5% for lipase, 3.9% for alanine aminotransferase, and 3.9% for aspartate aminotransferase.
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