Larson, Tim

8507 Background: Problems with sexual functioning are an issue negatively affecting the quality of life of female cancer survivors. Testosterone has been implicated as an important hormone in sexual functioning such as libido. Studies of transdermal testosterone have shown benefit in enhancing libido in women who have been diagnosed with hypoactive sexual desire disorder after bilateral oophorectomy. This phase III placebo-controlled clinical trial evaluated whether transdermal testosterone would increase libido in female cancer survivors. Methods: Women with a history of cancer, currently without evidence of disease, were eligible if they reported a decrease in sexual desire and had a sexual partner. Women must have been postmenopausal. Eligible women were randomized to receive 2% testosterone in Vanicream (10 mg daily) versus placebo Vanicream for four weeks, then crossed over to the opposite treatment. The primary endpoint, libido, was measured via the desire subscales of the Changes in Sexual Functioning Questionnaire (CSFQ), which were completed at baseline and at the end of 4 and 8 weeks of treatment. The primary endpoint was the average intra-patient change from baseline to four weeks in the CSFQ subscales between the two arms. A total of 64 patients per group were needed to provide 80% power to detect a difference of 8 units between the treatment means. Two-sided alternative hypothesis testing and a 5% Type I error rate were used. Results: One hundred fifty women were enrolled onto this study. Complete data were available for 132 women. For those on active testosterone cream, serum bioavailable testosterone levels increased significantly over placebo, with a mean change from baseline of 12 and 10 ng/dl for the first and second period, respectively (p<.0001). The average intra-patient change from baseline to week 4 in libido was 5.5 on testosterone and 4.4 on placebo (p=0.58). No carryover effect was detected. The difference in average intra-patient changes from baseline for the entire crossover design between the two arms was only 1.1 points (95% confidence interval of -1.2 to 3.4, p=0.35). Conclusion: Testosterone is not a panacea for libido troubles in women with a history of cancer. Further studies are needed to determine whether there is a role for transdermal testosterone in this population. No significant financial relationships to disclose.

677 Background: Napabucasin a first-in-class cancer stemness inhibitor in clinical development, suppresses cancer stemness by targeting Stat3-driven gene transcription. Preclinically, potent and broad-spectrum anti-cancer activity was observed in vitro and in vivo, alone and in combination with other agents. In a phase 1 study, napabucasin monotherapy was well tolerated with encouraging signs of anti-tumor activity at the RP2D of 500 mg BID. Methods: The current open-label, multi-center study includes phase II expansion in pts with refractory, K- Raswt mCRC to confirm safety and anti-tumor activity of napabucasin administered orally at 480mg BID in combination with panitumumab (6mg/kg bi-weekly). Results: 72 pts were enrolled, 48 pts were evaluable by RECIST of which 7 (15%) and 41 (85%) had 2 or >3 prior treatment lines, respectively. Of the 48 evaluable pts, 64.6% (31/48) were previously treated with an anti-EGFR agent. No new adverse events (AEs) were observed and most common AEs included grade 1/2 diarrhea, nausea, abdominal cramps, and vomiting. Among 48 pts enrolled who received RECIST evaluation, Disease Control Rate (DCR) was observed in 25 pts (52.1%) of which 3 pts achieved PR (6%) and 22 pts achieved SD (45%). Among 31 pts previously treated with anti-EGFR therapy, DCR was observed in 15 pts (48%) compared with DCR of 59% observed in 10 out of 17 anti-EGFR naïve pts receiving a scan. Conclusions: This phase II study confirmed that napabucasin can be safely combined with panitumumab at full dose and shows encouraging anti-tumor activity in pts with K- Ras wt mCRC, regardless of prior anti-EGFR exposure, suggesting that napabucasin may sensitize pts to repeat anti-EGFR therapy. Clinical trial information: NCT01776307. [Table: see text]

359 Background: GA, FOLFIRINOX and FOLFIRI are standard chemotherapy (CTX) regimens for mPC.The optimal introduction of these regimens following GA is not known. This phase II study evaluated 2 different approaches to this question. Methods: Eligibility criteria included 1) untreated mPC, 2) ECOG PS 0/1, 3) organ function adequate for Rx. Patients (pts) were treated according to one of 2 methods following GA given per standard dose/schedule: FOLFIRINOX (bolus 5-FU omitted) for up to 12 cycles at 24 weeks or at time of disease progression (S); or GA alternating with FOLFIRI q8 weeks up to 48 weeks total Rx (A). Results: 54 evaluable pts (28S, 26A) were enrolled . Pt characteristics included median age 65, M/F 48/52% , liver involvement 89%. 17/53 pts (31%) did not achieve disease control at 8 weeks (8 toxicity/complications , 6 disease progression, 3 declined further protocol therapy). Of the remaining 37 pts, 24/13 were treated with S/A regimens, respectively. Grade ≥ 3 treatment toxicities reported while on study with frequency ≥ 10% included anemia 21%, neutropenia 43%, thrombocytopenia 15%, and fatigue 22%. Grade ≥ 3 neuropathy occurred in 8% of pts. For all 54 pts using RECIST 1.0, CR/PR/SD/DC was 2 (4%)/20 (37%)/19 (35%)/41(76%). Ca19.9 response ≥ 90% was seen in 20/37 (54%). For all pts, median OS was 12.3 months ( 95% CI 8.6-14.5 mo); 12 and 24 mo OS was 51% and 11%, respectively. For the 37 pts with DC on GA at 8 weeks (calculated from start Rx) median OS was 13.5 mo (95% CI 10.7-15.4 mo); 12 and 24 mo OS was 55% and 16% , respectively. No statistically significant differences were seen between S and A with respect to toxicity, response or survival. Conclusions: 1) As opposed to introduction of 5FU-based CTX at the time of disease progression/prohibitive toxicity, introduction prior to that time may be at least comparable regarding both toxicity and OS. 2) This approach may further enhance OS in pts who achieve DC on GA at 8 weeks. 3) Neither S nor A method of 5FU-based CTX introduction following GA was clearly superior in this study. 4) How best to combine 5FU-based combination CTX following GA in mPC merits further study. Supported by the Seena Magowitz Foundation.