Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Radical -xh acid – or anhydride – acid halide or salt thereof...
Reexamination Certificate
2002-03-15
2004-04-20
Jones, Dwayne C. (Department: 1614)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Radical -xh acid, or anhydride, acid halide or salt thereof...
C514S185000, C514S545000, C514S576000, C514S578000
Reexamination Certificate
active
06723750
ABSTRACT:
BACKGROUND
The present invention relates to methods for treating pre-melanomas. In particular the present invention relates to methods for treating a pre-melanoma cell or condition using a photosensitive agent.
Photodynamic Therapy
Photodynamic therapy (PDT) is the use of an agent, given orally, intravenously, or topically, that can be activated or energized by light to inactivate or to cause necrosis of a target tissue in which the agent has accumulated. Activation of the agent results in the formation of new molecules and free radicals that form other chemicals that, in turn, can destroy the target tissue to varying extents or otherwise have a deleterious effect on the target tissue. Thus, photodynamic therapy involves the application of a photosensitive (photochemotherapeutic) agent to an affected area of the body, followed by exposure of the photosensitive agent to light of a suitable wavelength to activate the photosensitive agent and convert it into a cytotoxic form, whereby the affected cells are killed or their proliferative potential is diminished.
A photosensitive agent can exert its desired effects by a variety of mechanisms, directly or indirectly. Thus for example, a photosensitizer can become directly toxic when activated by light, whereas other photosensitive agents act to generate toxic species, for example, oxidizing agents such as singlet oxygen or other oxygen-derived free radicals, which are extremely destructive to cellular material and biomolecules such as lipids, proteins and nucleic acids.
PDT is not effective to treat thick lesions such as the skin cancer melanoma. Hence, PDT is not used to treat melanoma. Karrer, S., et al.,
Role of Lasers and photodynamic therapy in the treatment of cutaneous malignancy
, Am J Clin Dermatol 2001;2(4):229-37. See also Brown J. E., et al.,
Photodynamic therapy—new light on cancer treatment
, JSDC 115;249-253:1999.
Photodynamic therapy has been used to treat various superficial (i.e. thin, exterior, surface lesions) abnormalities or disorders of the skin as well as to treat macular degeneration. Thus, PDT has been used to treat various cancerous lesions, such as basal cell carcinoma including certain non-malignant lesions, and superficial skin lesions such as actinic keratoses (“AKs”) and psoriasis.
The PDT topical agent 5-aminolevulinic acid (5-ALA) has been used to selectively photosensitize the atypical cells of an AK lesion. Approximately 14 to 18 hours following application of the 5-ALA, the skin is exposed to a light source and the cells of the AK lesion are destroyed. Common side effects of PDT include erythema, stinging/burning, edema, and scaling or crusting of the lesion. The primary disadvantage of PDT to treat AK is the need for treatment over a 2-day period.
Precancerous Skin Lesions
Perhaps the most common precancerous skin lesion is actinic keratose (AK), also known as solar keratoses, which are common, sun-induced precancerous skin lesions that are confined to the epidermis. AK typically appears as circumscribed, rough, scaly patches on sun exposed skin, ranging from flesh-colored to reddish brown. Due to their distinctive roughened quality, AKs are easy to detect by palpation or by visualization. AKs are usually 1 to 3 mm in diameter, but may be larger in size and may appear in clusters. AKs are dynamic in nature. Although most AKs are asymptomatic, some may exhibit signs and symptoms such as thickening, burning, tenderness, or itching. AKs may also progress to squamous cell carcinoma (SCC), a form of skin cancer. AKs are most prevalent in fair-skinned individuals with a history of significant sun exposure. The prevalence of AKs increases with advancing age, and AKs are more common in men than women. AKs are more common in immunosuppressed patients and in patients with some genetic disorders (such as xeroderma pigmentosum). Due to high rates of prevalence and incidence, destruction of AKs is the most commonly performed outpatient dermatologic procedure in the United States.
The current management options for visible or easily perceived and diagnosed precancerous dermatological lesions such as AKs include cryosurgery with liquid nitrogen, topical treatments, and curettage. Other less common treatments include dermabrasion, excision, chemical peels, laser therapy, and photodynamic therapy.
Topical treatments, such as the chemotherapeutic agent 5-fluorouracil (5-FU), are most commonly used for patients with multiple lesions. The 5-FU cream is applied to the entire region that is affected, and the recommended course of treatment involves several applications per day over a 2 to 4 week time span. 5-FU selectively targets the damaged skin, causing an inflammatory response with erythema, necrosis, and erosion. Numerous side effects are associated with 5-FU, including pain or irritation, tenderness, ulceration, burning, and inflammation. As a result, patient compliance is a significant concern with this treatment.
Curettage, which involves the use of a curette to scrape away the lesion, is another common method of treatment for easily perceptible precancerous skin lesions. In some instances, curettage may be used in combination with electrosurgery to stop bleeding or apply more damage to the affected area. The primary advantage of curettage is the ability to submit the specimen for histologic analysis, particularly in cases where invasive squamous cell carcinoma is suspected. Disadvantages of curettage include the need for local anesthesia and the potential for scarring.
Melanoma and Pre-Melanoma
Melanoma is a type of potentially fatal skin cancer. A melanoma tumor develops from abnormal melanocytes in the lower epidermis. A melanocyte is a pigment cell which can become abnormal to varying degrees. The highest degree of abnormality of a melanocyte cell is to become a melanoma cell. A melanoma cell is a malignancy (i.e. a cancer or tumor cell) that invades and destroy surrounding tissues and can metastasize to distant sites in the body via the blood and lymph systems.
Melanomas are graded according to the deepest depth to which they penetrate the skin tissue. The depth may be described in terms of millimeters (Breslow) or by the depth level of various structures in the skin tissue to which the melanoma has penetrated. Melanoma is curable in its earliest phases and can arise on its own or from an atypical or unusual mole. More than 90% of melanomas occur on the visible portions of the body, that is on the skin.
The incidence and mortality rates of malignant melanoma continue to rise dramatically throughout the world. In the United States, it is estimated that nearly one in 90 Americans will develop melanoma. Melanoma is one of the most feared neoplasms because of the high mortality associated with metastasis. Melanomas usually metastasize first via the lymphatic system, with involvement of regional nodes, and then via blood vessels, with dissemination to subcutaneous tissue and to the liver, lungs, and brain. The presence of regional lymph node metastasis is predictive of a poor prognosis.
As set forth, melanomas arise from melanocytes and are typically pigmented (melanotic) due to accumulation of melanin, which imparts a dark color to melanomas. Some melanocytes may be less well differentiated and therefore produce little or no melanin. Melanomas arising from melanocytes can be nonpigmented or amelanotic.
Approximately 70 percent of melanomas are of the superficial spreading type. Generally, this type of melanoma is characterized by a pre-existing mole that slowly changes over a period of one to five years which is then followed by a period of rapid changes close to the time that the melanoma is diagnosed. Typically, this type of melanoma first appears as a very dark area in an existing mole. As the pre-melanoma enlarges, the edges usually appear notched or indented. Superficial spreading melanoma may appear anytime after puberty and is seen more often in women than in men.
Nodular melanoma is the second most common type of melanoma, accounting for approximately 15 to 30 percent of cases. These melanomas usua
Allergan Inc.
Donovan Stephen
Jones Dwayne C.
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