Managing AEs in Metastatic CSPC: TROPIC and CARD Trials

Charles Ryan, MD: A lot of what we know about the toxicity of chemotherapy comes from what we know from the TROPIC study, which was the study that led to the approval of cabazitaxel, and that carried forward on to CARD.

There was not a new signal. There were not new toxicities that were shown to develop in the CARD study. They weren’t really present in the TROPIC study.

In that setting the main toxicity that one needs to be aware of is hematologic toxicity. In fact, that’s really it. In my experience, and the data seem to support it, neuropathy, for example, is not so much worse.

There was a signal about some adverse events and diarrhea in the TROPIC study. That has not really carried forward quite so much, but it does happen. Patients do develop some mild diarrhea. It’s very manageable in the case of cabazitaxel.

For the most part, one can expect neutropenia in patients. And if not adequately managed or prevented, neutropenic fever can occur in anywhere from 5% to 15% of patients. It’s really clinician’s choice about whether they use up-front growth factor support. Keep in mind that the studies comparing the 2 doses of cabazitaxel, 20 mg/m2 and 25 mg/m2, did suggest that there was greater hematologic toxicity in the 25 mg/m2 dose.

If you’re using that dose, I recommend serious consideration of growth factor support. If you’re using the lower dose, you may still get it. You also have the option of choosing 1 of those 2 doses in the clinic at this time.

But there were data that suggest that there really wasn’t much of a difference. For many, 20 mg/m2 is the dose, even though 25 mg/m2 has been used in some other studies.

With regard to other hematologic toxicities, thrombocytopenia can occur. Although grade 3 and 4 were clinically significant, thrombocytopenia is actually quite rare.

Transcript edited for clarity.

Case: A 67-Year-Old Male with Metastatic Castrate-Sensitive Prostate Cancer

Initial presentation

• A 67-year-old active man presented with intermittent back pain and loss of appetite
• PMH: unremarkable
• FH: the patient’s father suffered a myocardial infarction at age 69; paternal grandmother had dementia; no known family history of cancer
• PE: DRE revealed asymmetric enlarged prostate; PE otherwise unremarkable
  
  

Clinical workup

• Core needle biopsy with TRUS showed adenocarcinoma of prostate
  • Stage T2N0M1b
  • Grade group 3
• Bone scan reveal 3 spinal lesions (T10, L2, L3) and 1 near the left iliac crest
• Abdominal and pelvic CT scan showed no other organ metastases
• PSA 24.9 ng/mL
  
  

Treatment and Follow-Up

• The patient was counselled on treatment options; he expressed concern regarding long-term AR exposure
• DOCE + ADT was initiated, 6 cycles were well-tolerated; PSA 6.2 ng/mL
• 2-year follow-up PSA 10.8 ng/mL; continued treatment regimen
  • 5 months later he reported increasing back pain and difficulty walking
  • PSA 21.4 ng/mL
  • PSADT 5.1 months
  • No new bone lesions on imaging
• Abiraterone 1000 mg PO qDay + prednisone 5 mg PO q12hr was initiated
• 1 year later PSA 30.2 ng/mL
  • Abdominal/pelvic CT showed multiple new small liver lesions, 1 new vertebral lesion and 1 new appendicular lesion
• Treatment with cabazitaxel 20 mg/m2 IV q3W + prednisone 10 mg PO qDay was initiated