E’ la triplice ”alendronato + calcio + vitamina D” a portare un aumento significativo della densità minerale ossea alla spina dorsale, all’anca e al trocantere, secondo lo studio ACTG 5163. La differenza è data dalla aggiunta di alendronato, ben tollerato dai pazienti, rispetto alla sola duplice:”calcio + vitamina D”, inefficace. Lo studio mostra come la somministrazione una volta alla settimana di alendronato (70 mg) è sicura ed efficace nel trattamento della diminuzione della densità minerale ossea in persone con HIV.

Dello studio ACTG 5162 sono stati presentati i risultati a 48 settimane. Importante, da sottolineare, che i cambiamenti dalla settimana 0 alla settimana 24 sono fortemente predittivi dei cambiamenti dalla settimana 0 alla 48.

Complementi in inglese

Decreased bone mineral density is prevalent in HIV-infected patients. Bisphosphonates, potent inhibitors of bone resorption, are currently the mainstay of treatment for postmenopausal and male osteoporosis in the HIV uninfected; however, their efficacy and safety in HIV-infected patients remain unclear.

Methods: A5163 was a prospective, randomized, placebo-controlled multicenter trial to evaluate the effectiveness of calcium and vitamin D supplementation with or without once-weekly alendronate (70 mg) in improving bone mineral density in HIV-infected individuals with lumbar spine t-scores -1.5. The study was powered to detect differences of 3.5% between arms and to evaluate moderate effects of gender in the response to therapy. All DEXA scans were analyzed centrally, blinded by arm.

Results: The 82 patients enrolled were 71% males, 77% white, with a baseline median age of 48 years. Median CD4 was 469 cells/mm3 and 91% had HIV RNA <400 copies/mL. Median baseline lumbar spine t-score was -2.1.

Compared with calcium/vitamin D, alendronate + calcium/vitamin D resulted in improvements in lumbar spine (3.38% vs 1.10%, p = 0.03), total hip (3.95% vs 1.31%, p = 0.004), and trochanter (4.52% vs 0.72%, p = 0.03), but not femoral neck (2.21% vs 1.24%, p = 0.35). There was at least a trend toward increase in the bone mineral density values in calcium/vitamin D at lumbar spine, total hip and femoral neck, with p = 0.08, 0.03, and 0.07 respectively, compared to baseline. Black race was associated with a smaller change from baseline in bone mineral density of lumbar spine with alendronate. There were no apparent gender differences in the responses to therapy. Alendronate was well tolerated, without significant adverse events.

There were more signs/symptoms of grade >/=3 in placebo arm (15% vs 0% in the alendronate arm, p=0.01); no difference between treatment arms in grade >/=3 lab toxicities (15% on placebo vs 17% on alendronate, p>0/9); no discontinuation related to toxicity. 21% of patients changed ARV during study (5 TDF), results unchanged when these 5 subjects were excluded.

Fonte: CROI abs + NATAP