More from the GU Oncology Symposium — a wrap-up

Looking through my assorted notes from the meeting this morning after getting home late last night, there are four other poster presentations that are worth commenting on very specifically, and then a general comment that I would add.

First, with respect to abiraterone acetate, Ryan et al. presented data from another Phase II clinical trial, but this time in patients who had not received prior taxane therapy. The study enrolled 31 patients with bone, nodal, and visceral metastases who met strict criteria for castration-resistant prostate cancer but who had not received either chemotherapy or ketoconazole therapy of any type. The short-term activity of abiraterone in these patients was impressive: 8/31 patients (25.8 percent) had a 12-week decline in their PSA level of ≥ 90 percent, and an additional 14/31 (45.2 percent) had a decline of ≥ 50 percent. Two patients apparently achieved undetectable PSA levels. The median time to PSA progression had not been reached at 300 days after initiation of treatment. There were some significant adverse reactions to abiraterone treament, however. These included six cases of Grade 3 toxicities and two Grade 4 toxicities (bone pain and dizziness). Abiraterone is clearly not a drug without risk for side effects. The authors concluded their poster by stating that, “Abiraterone acetate was well-tolerated and demonstrates considerable activity in the pre-chemotherapy setting as a secondary hormonal therapy.” We have previously noted that the US developer of the drug is projecting initiation of Phase III trials in chemotherapy-naive patients in March this year.

Similarly, Scher et al. reported preliminary data from an ongoing Phase I-II clinical trial of MDV3100 in castration-resistant prostate cancer. This trial has enrolled 140 patients in total, and detailed data is not available on all of these patients as yet. What was clear from the poster was that time that patients stayed on treatment (as a surrogate for time to disease progression) varied between the patients who had had prior chemotherapy and the patients who had not had prior chemotherapy. In the prior-chemotherapy patients the median time on treatment was 145 days; in the chemotherapy-naive patients the time on treatment was 276 days. The most commonly observed adverse reaction to MDV3100 was fatigue, but this caused only one patient to discontinue treatment. Two patients receiving very high doses of MDV3100 were reported to have had seizures. However, both patients were apparently taking concomitant medications known to cause seizures. There is clearly a need to be cautious in the use of MDV3100 in patients receiving drugs like prochlorperazine, olanzapine, and mirtazipine. We expect MDV3100 to progress into Phase III clinical trials in the near future at a dose of 240 mg/day (which is less than half of the dose at which the two patients exhibited seizures).

Elsewhere we have commented on the issue of anxiety in men who are on active surveillance protocols for the management of low risk, early stage prostate cancer. A study by van den Bergh et al. in Rotterdam has now specifically addressed the issue of  “Anxiety and distress during active surveillance for early prostrate cancer.” In this study, the authors assessed four specific measures of anxiety and distress using six different validated questionnaires, and 129/150 of their patients (89 percent) completed all questionnaires.

In general, their data demonstrated that most men adhered to a protocol-based active surveillance regimen without significant levels of anxiety or distress. There appeared to be several factors of importance in how patients reacted to this form of management:

  • The patient’s perception of the importance of the physician’s role in shared decision-making when the patient had a higher level of decisional conflict
  • Better physical health of the patient in general, with a lower level of depression
  • A “neurotic personality” associated with higher levels of depression as well as general and prostate cancer-specific anxiety
  • Higher PSA levels and therefore higher prostate cancer-specific anxiety

The authors suggest that their data may help to determine which types of patient may more appropriate for management with active surveillance as well as which patients may need other forms of supportive care.

Finally, it is worth commenting on a cost issue. Gupta et al. tracked the hospital-associated costs of three different types of radical prostatectomy among 645 consecutive patients at their institution between September 2003 and April 2008. Please note that these costs do not include fees to the surgeon or other medical personnel such as the anesthesiologist. These are the hospital overhead costs only. They showed that the average total direct costs to the hospital per procedure were as follows:

  • For an open radical retropubic prostatectomy or RRP: $3,631 (range $3.083 to $4,591)
  • For a non-robotic laparoscopic radical prostatectomy or LPR: $5,636 (range $4,979 to $6,227)
  • For a robot-assisted laparoscopic prostatectomy or RALP: $6,623 (range $5,871 to $7,607)

The major difference between the costs of the procedures was in the operating room-related costs and the cost of surgical supplies. However, it is also worth noting that these costs do not take any account of the overhead of purchasing and maintaining the da Vinci robotic equipment.

The “New” Prostate Cancer InfoLink does not include this last study to make any sort of point about the relative clinical benefits of differing types of surgery. Rather, we thought it was appropriate, in these times of economic difficulty for many, to point out how “cool” technology can drive up the cost of health care very quickly.

I should conclude by noting just how many posters at this meeting provided laboratory and animal model data about other drugs in development for late stage prostate cancer. We will report more on some of these agents as they start to move into Phase I/II or Phase II clinical trials. At present, many of these drugs show limited degrees of potential for use in prostate cancer, but the continuing and growing interest in this area is encouraging for the patient community.

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