Regrel

Regrel (becaplermin) Gel is indicated for the treatment of lower extremity diabetic neuropathic ulcers that extend into the subcutaneous tissue or beyond and have an adequate blood supply, when used as an adjunct to, and not a substitute for, good ulcer care practices including initial sharp debridement, pressure relief and infection control.

Limitations Of Use

The efficacy of Regrel Gel has not been established for the treatment of pressure ulcers and venous stasis ulcers and has not been evaluated for the treatment of diabetic neuropathic ulcers that do not extend through the dermis into subcutaneous tissue (Stage I or II, IAET staging classification) or ischemic diabetic ulcers.

The effects of becaplermin on exposed joints, tendons, ligaments, and bone have not been established in humans.

Regrel Gel is a non-sterile, low bioburden preserved product. Therefore, it should not be used in wounds that close by primary intention.

For topical use; not for oral, ophthalmic or intravaginal use.

The amount of Regrel Gel to be applied will vary depending upon the size of the ulcer area. To calculate the length of gel to apply to the ulcer, measure the greatest length of the ulcer by the greatest width of the ulcer in either inches or centimeters. To calculate the length of gel in inches, use the formula shown below in Table 1, and to calculate the length of gel in centimeters, use the formula shown below in Table 2.

Table 1: Formula to Calculate Length of Gel in Inches to Be Applied Daily

Using the calculation, each square inch of ulcer surface will require approximately 2/3 inch length of gel squeezed from a 15g tube, or approximately 1 1/3 inch length of the gel from a 2g tube (physician sample). For example, if the ulcer measures 1 inch by 2 inches, then a 1 1/4 inch length of gel should be used for 15g tubes (1 × 2 × 0.6 = 1 1/4) and 2 3/4 inch gel length should be used for a 2g tube (1 × 2 × 1.3 = 2 3/4).

Table 2: Formula to Calculate Length of Gel in Centimeters to Be Applied Daily

Using the calculations for ulcer size in centimeters, each square centimeter of ulcer surface will require approximately a 0.25 centimeter length of gel squeezed from a 15g tube, or approximately a 0.5 centimeter length of gel from a 2g tube. For example, if the ulcer measures 4 cm by 2 cm, then a 2 centimeter length of gel should be used for a 15g tube [(4 × 2) ÷ 4 = 2] and a 4 centimeter length of gel should be used for a 2g tube [(4 × 2) ÷ 2 = 4].

The amount of Regrel Gel to be applied should be recalculated by the physician or wound caregiver at weekly or biweekly intervals depending on the rate of change in ulcer area. The weight of Regrel Gel from 15g tubes is 0.65g per inch length and 0.25g per centimeter length.

To apply Regrel Gel, the calculated length of gel should be squeezed on to a clean measuring surface, e.g., wax paper. The measured Regrel Gel is transferred from the clean measuring surface using an application aid and then spread over the entire ulcer area to yield a thin continuous layer of approximately 1/16 of an inch thickness. The site(s) of application should then be covered by a saline moistened dressing and left in place for approximately 12 hours. The dressing should then be removed and the ulcer rinsed with saline or water to remove residual gel and covered again with a second moist dressing (without Regrel Gel) for the remainder of the day. Regrel Gel should be applied once daily to the ulcer until complete healing has occurred. If the ulcer does not decrease in size by approximately 30% after 10 weeks of treatment or complete healing has not occurred in 20 weeks, continued treatment with Regrel Gel should be reassessed. The step-by-step instructions for applying Regrel Gel for home administration are described under “Patient Counseling Information”.

Regrel Gel is contraindicated in patients with known neoplasm(s) at the site(s) of application.

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

Cancer And Cancer Mortality

Regrel Gel contains becaplermin, a recombinant human platelet-derived growth factor, which promotes cellular proliferation and angiogenesis. The benefits and risks of becaplermin treatment should be carefully evaluated before prescribing. Becaplermin should be used with caution in patients with a known malignancy.

Malignancies distant from the site of application have occurred in becaplermin users in both a clinical study and postmarketing use, and an increased rate of death from systemic malignancies was seen in patients who have received 3 or more tubes of Regrel Gel.

In a follow-up study, 491 (75%) of 651 subjects from two randomized, controlled trials of becaplermin gel 0.01% were followed for a median of approximately 20 months to identify malignancies diagnosed after the end of the trials. Eight of 291 subjects (3%) from the becaplermin group and two of 200 subjects (1%) from the vehicle/standard of care group were diagnosed with cancers during the follow-up period, a relative risk of 2.7 (95% confidence interval 0.6–12.8). The types of cancers varied and all were remote from the treatment site.

In a retrospective study of a medical claims database, cancer rates and overall cancer mortality were compared between 1,622 patients who used Regrel Gel and 2,809 matched comparators. Estimates of the incidence rates reported below may be under-reported due to limited follow-up for each individual.

• The incidence rate for all cancers was 10.2 per 1,000 person years for patients treated with Regrel Gel and 9.1 per 1,000 person years for the comparators. Adjusted for several possible confounders, the rate ratio was 1.2 (95% confidence interval 0.7–1.9). Types of cancers varied and were remote from the site of treatment.
• The incidence rate for mortality from all cancers was 1.6 per 1,000 person years for those who received Regrel Gel and 0.9 per 1,000 person years for the comparators. The adjusted rate ratio was 1.8 (95% confidence interval 0.7–4.9).
• The incidence rate for mortality from all cancers among patients who received 3 or more tubes of Regrel Gel was 3.9 per 1,000 person years and 0.9 per 1,000 person years in the comparators. The adjusted rate ratio for cancer mortality among those who received 3 or more tubes relative to those who received none was 5.2 (95% confidence interval 1.6–17.6).

Application Site Reactions

If application site reactions occur, the possibility of sensitization or irritation caused by parabens or m-cresol should be considered. Consider interruption or discontinuation and further evaluation (e.g. patch testing) as dictated by clinical circumstances.

Patient Counseling Information

Counsel patients to review and discuss any questions or concerns with their healthcare provider before starting Regrel and at regular intervals while receiving Regrel.

Patients should be advised that:

• they should read the medication guide;
• hands should be washed thoroughly before applying Regrel Gel;
• the tip of the tube should not come into contact with the ulcer or any other surface; the tube should be recapped tightly after each use;
• a cotton swab, tongue depressor, or other application aid should be used to apply Regrel Gel;
• Regrel Gel should only be applied once a day in a carefully measured quantity. The measured quantity of gel should be spread evenly over the ulcerated area to yield a thin continuous layer of approximately 1/16 of an inch thickness. The measured length of the gel to be squeezed from the tube should be adjusted according to the size of the ulcer. The amount of Regrel Gel to be applied daily should be recalculated at weekly or biweekly intervals by the physician or wound care giver.

Step-by-step instructions for application of Regrel Gel are as follows:

• Squeeze the calculated length of gel onto a clean, firm, nonabsorbable surface, e.g., wax paper.
• With a clean cotton swab, tongue depressor, or similar application aid, spread the measured Regrel Gel over the ulcer surface to obtain an even layer.
• Cover with a saline moistened gauze dressing.
  • after approximately 12 hours, the ulcer should be gently rinsed with saline or water to remove residual gel and covered with a saline-moistened gauze dressing (without Regrel Gel);
  • it is important to use Regrel Gel together with a good ulcer care program, including a strict non-weight-bearing program;
  • excess application of Regrel Gel has not been shown to be beneficial;
  • Regrel Gel should be stored in the refrigerator. Do not freeze Regrel Gel;
  • Regrel Gel should not be used after the expiration date on the bottom, crimped end of the tube.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Becaplermin was not genotoxic in a battery of in vitro assays (including those for bacterial and mammalian cell point mutation, chromosomal aberration, and DNA damage/repair). Becaplermin was also not mutagenic in an in vivo assay for the induction of micronuclei in mouse bone marrow cells.

Carcinogenesis and reproductive toxicity studies have not been conducted with Regrel Gel.

Animal Toxicology And/Or Pharmacology

In nonclinical studies, rats injected at the metatarsals with 3 or 10 mcg/site (approximately 60 or 200 mcg/kg) of becaplermin every other day for 13 days displayed histological changes indicative of accelerated bone remodeling consisting of periosteal hyperplasia and subperiosteal bone resorption and exostosis. The soft tissue adjacent to the injection site had fibroplasia with accompanying mononuclear cell infiltration reflective of the ability of PDGF to stimulate connective tissue growth.

Use In Specific Populations

Pregnancy

Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women treated with Regrel Gel. Regrel Gel should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal reproduction studies have not been conducted with Regrel Gel.

Nursing Mothers

It is not known whether becaplermin is excreted in human milk. Because many drugs are secreted in human milk, caution should be exercised when Regrel Gel is administered to nursing women.

Pediatric Use

Safety and effectiveness of Regrel Gel in pediatric patients below the age of 16 years have not been established.

Geriatric Use

Among patients receiving any dose of Regrel Gel in clinical studies of diabetic lower extremity ulcers, 150 patients were 65 years of age and older. No overall differences in safety or effectiveness were observed between patients < 65 years of age and patients ≥ 65 years of age. The number of patients aged 75 and older were insufficient (n=34) to determine whether they respond differently from younger patients.

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.

In a follow-up study from two randomized, controlled trials, an increased rate of cancer remote from the becaplermin treatment site was observed in subjects treated with Regrel Gel.

In clinical trials, erythematous rashes occurred in 2% of patients treated with Regrel Gel (and good ulcer care) or placebo (and good ulcer care), and none in patients receiving good ulcer care alone. Patients treated with Regrel Gel did not develop neutralizing antibodies against becaplermin.

Postmarketing Experience

An increased rate of mortality secondary to malignancy was observed in patients treated with 3 or more tubes of Regrel Gel in a postmarketing retrospective cohort study.

Burning sensation at the site of application and erythema have been reported during post-approval use of Regrel Gel. Because post-approval adverse reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to the drug.

There are no data on the effects of becaplermin overdose.

Clinical pharmacodynamic studies have not been conducted.

Ten patients with Stage III or IV (as defined in the International Association of Enterostomal Therapy (IAET) guide to chronic wound staging,1,2 lower extremity diabetic ulcers received topical applications of becaplermin gel 0.01% at a dose range of 0.32–2.95 μg/kg (7μg/cm²) daily for 14 days. Six patients had non-quantifiable PDGF levels at baseline and throughout the study, two patients had PDGF levels at baseline which did not increase substantially, and two patients had PDGF levels that increased sporadically above their baseline values during the 14 day study period.