A Phase II trial of 8 weeks of degarelix for prostate volume reduction: Efficacy and hormonal recovery.

PURPOSE: The purpose of this study was to determine the efficacy of 8 weeks of degarelix for prostate downsizing before interstitial brachytherapy. We also report associated toxicity and the time course of endocrine recovery over the following 12 months. METHODS AND MATERIALS: Fifty patients were accrued to an open-label Phase II clinical trial (www.clinicaltrials.gov ID NCT01446991). Baseline prostate transrectal ultrasound (TRUS) was performed on all patients followed by degarelix administration and a repeat TRUS at Week 8. Brachytherapy was performed within 4 weeks of the 8-week TRUS for all patients who achieved suitable downsizing. RESULTS: The median prostate volume was reduced from 65.0 cc (interquartile range [IQR]: 55.2-80.0 cc) to 48.2 cc at 8 weeks (IQR: 41.2-59.3 cc), representing a median decrease of 26.2% (IQR: 21-31%). Functional recovery of testosterone within an age-adjusted normal range occurred at a median of 34.1 weeks (IQR: 28.2-44.5 weeks) from the date of the final injection. Despite this recovery, follicle-stimulating hormone and luteinizing hormone levels remained abnormally elevated throughout 12 months. Quality-of-life implications are discussed. CONCLUSIONS: Degarelix is effective for prostate downsizing before prostate brachytherapy with a median volume decrease of 26.2% by 8 weeks. Despite the short course of treatment and eventual testosterone recovery, follicle-stimulating hormone and luteinizing hormone remain elevated beyond 12 months. Further investigation with randomized comparisons to other hormonal agents is warranted.

Context-dependent latent inhibition in preweanling rats.

Preexposure to a conditioned stimulus (CS) usually weakens conditioning, an effect known as latent inhibition. Similar to other learning interference effects, latent inhibition has been characterized as context-dependent, which means that the magnitude of this effect can be attenuated by changing the context between the different phases of the procedure (e.g., preexposure and conditioning). Latent inhibition has been found with a variety of procedures in infant rats, but the few studies that examined the context-dependency of this phenomenon during this ontogenetic period found no context-change effect. The present study explored the context-dependency of latent inhibition during infancy using a conditioned taste aversion preparation and employing contexts enriched with distinctive odors to increase the possible efficacy of the context manipulation. Experiment 1 showed that three preexposures to the CS (saccharin) were sufficient to retard conditioning to the same CS, although this effect was also observed in a control group preexposed to an alternative taste stimulus (saline), in comparison with a non-preexposed control group. In Experiment 2a, the CS-preexposure effect was found to be specific to the preexposed CS when the number of preexposures was increased. This effect was revealed as context-dependent in Experiment 2b, since it was attenuated by changing the context between preexposure and conditioning. The present result is consistent with recent studies showing the context-dependency of extinction in preweanling rats, thus demonstrating these animals' capacity to learn about context early on in their development.