Mitomycin

Introduction Overview

Generic Name

mitomycin

Brand Name

Jelmyto

Dosage Form

kit for pyelocalyceal solution

Drug Class

Antibiotics / antineoplastics

Pharmacokinetics

Absorption:
Following instillation of up to 60 mg of mitomycin as Jelmyto into the pyelocalyceal system, systemic absorption is minimal and variable. Plasma concentrations of mitomycin measured up to 6 hours post-instillation ranged from 2.43 to 12.80 ng/mL, with an average peak concentration (Cmax) of approximately 6.24 ng/mL. This Cmax is estimated to be less than 1% of the levels achieved after intravenous administration, reflecting limited systemic exposure due to localized delivery. Minimal systemic absorption reduces systemic toxicity but continuous monitoring remains essential, considering individual variability.

Distribution:
Mitomycin, upon instillation, integrates into the urinary tract lining with limited systemic dissemination due to localized administration. Although systemic absorption is low, once in systemic circulation, mitomycin exhibits rapid distribution with affinity for tissues, particularly those with high mitotic activity. Data specific to Jelmyto's distribution post-instillation are limited, but it is expected that localized gel formation confines drug activity mainly to the urothelium of the upper tract.

Metabolism:
Mitomycin is primarily metabolized hepatically by enzymatic reduction processes and in other tissues capable of bioreductive activation. The metabolism involves bioactivation to reactive species that alkylate DNA. Notably, the metabolic clearance rate of mitomycin is inversely related to serum concentration due to saturation of degradative pathways, indicating nonlinear kinetics. In the context of Jelmyto, limited systemic absorption likely restricts extensive metabolism, but systemic metabolites may still form in trace amounts.

Elimination:
Mitomycin is predominantly eliminated unchanged through renal excretion. Following pyelocalyceal instillation, Jelmyto forms a semisolid gel that dissolves gradually with normal urine flow, releasing mitomycin over 4 to 6 hours. Approximately 10% of systemically absorbed mitomycin is excreted unchanged in the urine. Systemically absorbed mitomycin is rapidly cleared from serum, minimizing systemic accumulation. The localized gel properties facilitate sustained drug exposure to upper urinary tract urothelium while limiting systemic clearance demands.

Dosage Forms

Available Dosage Forms:
Jelmyto is supplied as a kit formulated for pyelocalyceal instillation. The kit contains two single-dose vials of mitomycin powder (40 mg each), which is sterile, lyophilized, and appears as a grey to greyish-purple cake or powder. It also includes one vial of 20 mL sterile hydrogel used for reconstitution. Once reconstituted, Jelmyto becomes a purple, viscous liquid or semisolid gel depending on temperature.

Dosages for Adults and Adolescents:
Jelmyto is indicated for adult patients with low-grade upper tract urothelial cancer (LG-UTUC). The recommended dose is 4 mg of mitomycin per mL, instilled via a ureteral catheter or nephrostomy tube once weekly for six weeks. The instillation volume is individualized based on pyelographic volumetric measurements but should not exceed 15 mL (60 mg total dose). For patients achieving complete response at 3 months, maintenance therapy can be administered monthly for up to 11 additional doses.

Specific Patient Populations:
Safety and efficacy have not been established in pediatric patients. Use in geriatric populations has been studied, with 75% of patients in clinical trials aged 65 or older, showing no differential response. Use in patients with severe renal impairment (glomerular filtration rate < 30 mL/min) is not recommended due to lack of data. Therapy is contraindicated in patients with perforation of the bladder or upper urinary tract.

Preparation and Handling:
Jelmyto must be reconstituted under chilled, aseptic conditions using sterile hydrogel to a concentration of 4 mg/mL. The reconstituted product exhibits reverse thermal gelation properties—forming a viscous liquid when chilled (-3°C to 5°C) for instillation and becoming a semisolid gel at room temperature. Reconstituted Jelmyto is stable for up to 96 hours at 20°C to 25°C and must be protected from light. Instillation should occur within one hour after chilling to maintain viscosity suitable for delivery.

Mechanism Of Action

Mitomycin, the active component of Jelmyto, is a potent alkylating agent that exerts cytotoxic effects primarily through DNA cross-linking. Upon reduction within cells, mitomycin forms reactive intermediates that covalently bind to DNA at guanine and cytosine residues, causing both inter- and intra-strand cross-links. This cross-linking inhibits DNA replication and transcription, leading to inhibition of cell proliferation and eventual programmed cell death in rapidly dividing cancer cells.

At the molecular level, the alkylation disrupts DNA double helix stability and prevents strand separation necessary for replication. This results in the accumulation of DNA damage, activation of DNA repair pathways, and induction of apoptosis when damage is irreparable. Higher concentrations of mitomycin can also suppress RNA and protein synthesis, further compromising cellular viability.

Jelmyto’s unique gel formulation allows for prolonged exposure of the urothelial lining of the upper urinary tract to mitomycin, facilitating sustained localized cytotoxicity with minimal systemic absorption. This pharmacological strategy enhances drug retention on tumor sites, increasing efficacy against papillary tumors of low-grade upper tract urothelial carcinoma.

Compared to systemic mitomycin administration, which circulates broadly and is associated with significant toxicity, Jelmyto’s localized delivery via pyelocalyceal instillation confines drug exposure, improving tolerability and safety. Clinical studies demonstrate Jelmyto’s ability to induce complete response in a significant proportion of patients with low-grade upper tract urothelial cancer, attributed to its targeted DNA-alkylating mechanism combined with gel-based drug delivery technology.

Pharmacological Actions

Alkylation and cross-linking of DNA leading to inhibition of DNA replication and transcription.
Suppression of RNA and protein synthesis at higher drug concentrations.
Localized cytotoxicity in upper urinary tract urothelium due to sustained drug release from semisolid gel formulation.
Induction of apoptosis in tumor cells through irreparable DNA damage.
Reduction of systemic toxicity through pyelocalyceal instillation and minimal systemic absorption.
Inhibition of tumor cell proliferation in low-grade upper tract urothelial carcinoma.
Exploitation of reverse thermal gelation properties for enhanced local drug retention.
Potential for nephrotoxicity and urothelial irritation due to localized drug activity.
Capacity to cause bone marrow suppression via systemic absorption despite localized administration.
Genotoxic and mutagenic effects observed in preclinical carcinogenicity studies.
Interference with cellular redox state and metabolism as part of antineoplastic activity.

Therapeutic Or Clinical Uses

Treatment of adult patients with low-grade upper tract urothelial cancer (LG-UTUC).
Non-invasive therapy option for patients with papillary tumors in the renal pelvis or calyces.
Instillation therapy via ureteral catheter or nephrostomy tube for localized urothelial carcinoma.
Use as primary treatment for treatment-naïve or recurrent LG-UTUC with measurable tumors.
Maintenance therapy following initial complete response to prolong disease remission.
Potential alternative to surgical management for select patients with upper tract urothelial carcinoma.
Treatment modality aimed at preserving renal function by avoiding nephroureterectomy.
Use in patients contraindicated for systemic chemotherapy due to toxicity concerns.
Local chemotherapy in patients with tumors not amenable to endoscopic resection.
Adjunct to tumor debulking procedures to reduce tumor burden and recurrence risk.
Application for patients ineligible or unwilling to undergo invasive surgical interventions.
Option for patients requiring bladder preservation strategies with upper tract urothelial involvement.

Side Or Adverse Effects

Ureteric obstruction, including ureteral stenosis, hydronephrosis, and urinary tract obstruction.
Flank pain associated with ureteral obstruction or inflammatory response.
Urinary tract infections, including pyelonephritis and fungal infections.
Hematuria manifesting as blood in urine or hemorrhagic urinary tract conditions.
Renal dysfunction, including acute kidney injury and renal impairment.
Nausea, vomiting, and abdominal pain as gastrointestinal side effects.
Fatigue, malaise, and asthenia indicating systemic effects.
Dysuria and pollakiuria due to urothelial irritation.
Bone marrow suppression causing thrombocytopenia, neutropenia, and anemia.
Hypoalbuminemia and electrolyte disturbances such as hypo/hypercalcemia, hyperkalemia, and hypernatremia.
Rash, dermatitis, pruritus, and other skin-related adverse events.
Pyrexia and chills as signs of systemic inflammatory or immune response.
Rare severe adverse events including urosepsis and cerebrovascular accidents.
Potential for treatment discontinuation due to severity of adverse reactions.
Possible urine discoloration to violet or blue hues post-instillation.

Precautions

Monitor patients closely for signs of ureteric obstruction and intervene promptly.
Frequent assessment of blood cell counts to detect bone marrow suppression.
Advise patients to avoid contact with urine for at least 6 hours post-instillation to prevent skin exposure.
Evaluate renal function prior to and during therapy; avoid use in severe renal impairment.
Use sodium bicarbonate oral premedication regimen to optimize urinary pH before instillation.
Implement careful handling and disposal procedures due to drug’s cytotoxicity and hazardous classification.
Ensure proper preparation under chilled, aseptic conditions to maintain drug stability and potency.
Instruct patients to maintain hydration and report symptoms such as flank pain or fever immediately.
Consider withholding diuretics around treatment to avoid altering drug clearance and urinary flow.
Avoid instillation in presence of urinary tract perforation to prevent extravasation and toxicity.
Use caution in elderly patients; monitor for increased susceptibility to adverse events.
Counsel patients on potential for urine discoloration to prevent undue alarm.
Advise against breastfeeding during and for 1 week after treatment due to unknown milk excretion.
Ensure effective contraception during therapy and for defined periods after last dose in males and females.
Coordinate multidisciplinary care to manage complications such as stent placement for obstruction.

Warnings

Risk of ureteric obstruction which may necessitate ureteral stenting or surgical interventions.
Potential for bone marrow suppression leading to thrombocytopenia, neutropenia, and anemia.
May cause fetal harm; contraindicated in pregnancy without effective contraception.
Not for intravenous, topical, or oral administration; exclusively for pyelocalyceal instillation.
Hazardous drug requiring special handling, preparation, and disposal protocols to protect healthcare workers.
Instillation must be completed within specified time frames to avoid gel solidification and delivery failure.
Patients should be monitored for renal function deterioration and signs of systemic toxicity.
Adverse reactions may require withholding or permanent discontinuation depending on severity.
Be alert for symptoms suggestive of urosepsis or systemic infection during treatment.
Potential for drug extravasation risks if urinary tract perforation is present, which contraindicates use.
In rare cases, severe adverse events including cerebrovascular accidents and failure to thrive have been reported.
Urine discoloration should not be mistaken for hematuria or other pathology without clinical correlation.
The gel property of the product requires specialized administration devices and training.
Therapy discontinuation rates are significant due to adverse event profile; patient counseling is essential.
The safety in pediatric population is unknown; use in this group is not recommended.

Contraindication

Perforation or tear (perforation) of the bladder or upper urinary tract.
Known hypersensitivity to mitomycin or any component of the formulation.
Patients unable to tolerate catheter-based procedures required for instillation.
Severe renal impairment (glomerular filtration rate < 30 mL/min) due to lack of safety data.
Pregnancy due to teratogenicity and embryo-fetal toxicity.
Administration by any route other than pyelocalyceal instillation (e.g., intravenous, oral, topical).
Use in patients with unresolved active urinary tract infections or severe urinary tract inflammation.
Known bleeding disorders or conditions predisposing to hemorrhagic complications without supervision.
Inability to comply with sodium bicarbonate premedication regimen and post-treatment urine handling instructions.
Presence of carcinoma in situ (CIS) or high-grade urothelial carcinoma without appropriate clinical assessment.

Drug Interactions

Use caution with drugs that suppress bone marrow function; concurrent use may exacerbate thrombocytopenia and neutropenia.
Potential interaction with diuretics; consider withholding diuretics one day prior to and up to 4 hours post-instillation.
No significant systemic drug interactions reported due to low systemic absorption; however, vigilance is recommended.
Avoid co-administration with other nephrotoxic agents to reduce risk of renal dysfunction.
Careful monitoring advised if combined with other chemotherapeutic agents due to cumulative toxicity.
No data available indicating interaction with oral or intravenous anticoagulants, but bleeding risk warrants caution.
Potential interactions with agents altering urinary tract mucosa should be considered to avoid enhanced toxicity.
Mitomycin metabolism via hepatic reductive enzymes may be influenced by concurrent drugs affecting liver function.
No known direct interactions with immunosuppressive or biologic agents used in urothelial cancer.
Interaction potential with agents influencing urinary pH or flow rate, possibly altering drug residence time.
Use with drugs causing electrolyte imbalance may compound electrolyte disturbances seen with Jelmyto.
Concurrent use of sodium bicarbonate required for administration; modifiers of acid-base balance should be managed accordingly.
No specific dietary interactions identified, but hydration status can affect drug elimination and efficacy.
Limited systemic exposure limits typical cytochrome P450-related interactions.
No documented interaction with vaccines; immunizations should be timed per oncologic guideline.

Preparations Of The Drug

Jelmyto is supplied as a two-component kit containing two sterile, lyophilized 40 mg vials of mitomycin powder for pyelocalyceal solution.
The kit includes a single 20 mL sterile hydrogel vial used as a reconstitution vehicle.
The mitomycin vials contain mitomycin 40 mg and mannitol 80 mg as inactive ingredient.
Sterile hydrogel consists of hydroxypropyl methylcellulose, poloxamer, polyethylene glycol, and water for injection.
Drug reconstitution involves mixing mitomycin powder with sterile hydrogel under chilled (2°C to 8°C) and aseptic conditions resulting in a 4 mg/mL concentration.
After reconstitution, the product forms a semisolid purple gel at room temperature and a viscous liquid upon chilling.
Preparation requires use of chilling block devices to maintain temperatures between -20°C and -12°C overnight for components before compounding.
Aseptic technique is critical during preparation to avoid contamination; shaking or inverting vials is contraindicated to maintain product integrity.
Vials and syringes must remain cold during preparation; difficulties in withdrawing or instilling the drug can be resolved by re-chilling.
Prepared admixture must be labeled with a discard date and stored protected from light at 20°C to 25°C for up to 96 hours before use.
Strict hazardous drug handling procedures should be followed throughout preparation and disposal phases.
Preparation includes sequential injection of sterile hydrogel and pre-wetting solution into mitomycin vials with repeated gentle swirling.
Final admixture is combined into a single vial for administration using specified accessories and devices such as Uroject12 Syringe Lever.
Pharmacy supplies must include dedicated vial and syringe adaptors, Luer Lock connectors, and sterile water as per instructions.
Dispensing requires placement of admixture vial in a light-protective bag for transport to treatment facility.