Silicon phthalocyanine (Pc 4) photodynamic therapy is a safe modality for cutaneous neoplasms: results of a phase 1 clinical trial.
BACKGROUND
Photodynamic therapy (PDT) is a non-invasive treatment for non-melanoma skin cancer. However, PDT systems currently used clinically have limitations such as pain and superficial tissue penetration. The silicon phthalocyanine Pc 4 is a second-generation photosensitizer with peak absorption in the far red at 675 nm.


OBJECTIVE
To assess the safety and tolerability of topically applied Pc 4 followed by red light (Pc 4-PDT) in treating cutaneous neoplasms.


METHODS
Forty three adults with a diagnosis of neoplasms including actinic keratoses, Bowen's disease, squamous cell carcinoma, basal cell carcinoma, or mycosis fungoides were treated with a single administration of Pc 4-PDT and followed for 14 days. The study utilized a light and Pc 4 dose escalation design in sequential groups of three subjects each.


RESULTS
Pc 4-PDT was well tolerated with no significant local toxicity or increased photosensitivity. It has promising biologic effects, particularly in mycosis fungoides where 14 of 35 subjects demonstrated a clinical response, which correlates with Pc 4-PDT-induced apoptosis, as measured by increased active caspase-3 in the treated skin lesions.


CONCLUSIONS
Pc 4-PDT is a safe and tolerable treatment modality that effectively triggers apoptosis in cutaneous neoplasms such as mycosis fungoides.
Department of Dermatology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio 44106, USA. elma.baron@uhhospitals.org
Elma D
ED
Baron
Christi L
CL
Malbasa
Diana
D
Santo-Domingo
Pingfu
P
Fu
Janine D
JD
Miller
Kaija K
KK
Hanneman
Andrew H
AH
Hsia
Nancy L
NL
Oleinick
Valdir C
VC
Colussi
Kevin D
KD
Cooper
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000188:drug therapy* / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007211:Indoles / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D017646:Organosilicon Compounds / Q000627:therapeutic use*; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000473:pathology; D016896:Treatment Outcome
D007211:Indoles; D017646:Organosilicon Compounds; D017319:Photosensitizing Agents; C082854:silicon phthalocyanine
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