Background: Regulatory T cells are increased in melanoma pts and are postulated to impair objective response to immune therapies. Pembro blocks programmed death receptor-1, reverses T-cell suppression and induces antitumor activity. Continuous low dose TMZ has immunomodulatory effects resulting in selective CD4+ lymphopenia of which the T-reg population of CD4+/CD25+ T cells could be decreased significantly. TMZ has demonstrated dramatic responses after IL-2 in metastatic melanoma pts. We evaluated responses with sequential TMZ after progression on pembro in pts with metastatic melanoma. Methods: Medical records of pts with metastatic melanoma treated with pembro and TMZ at Holden Comprehensive Cancer Center between 1/1/2011 and 8/31/2016 were reviewed. Recorded data included BRAF mutation status, treatment doses, serological markers, duration of treatment and treatment related responses (immune RECIST and RECIST 1.1). Results: Overall 10 pts (7 males, 3 females) with metastatic melanoma received sequential pembro followed by TMZ after disease progression or unacceptable toxicity. Eight were BRAF negative and 7 were pretreated with ipilimumab. Median age at time of initiating pembro (2 mg/kg every 3 weeks) was 64 years (range 33-75). Pts received a median of 4 doses (2-19). Median duration of treatment was 88 days (41-464) with stable disease in 3, progressive disease (PD) in 6 and 1 not evaluable for response. All pts thereafter received TMZ (75 mg/m2 daily for 6 weeks on 8 week cycle except 1 who received 200 mg/m2 for 5 days every 4 weeks) after a median of 21.5 days (12-34) from last pembro dose. Median duration on treatment with TMZ was 75 days (20-198) resulting in 1 complete response, 1 partial response, 6 PD and 2 not evaluable for response. Pts with response to TMZ had a higher median baseline lymphocyte count at the time of initiation of pembro (4131 vs. 1715 k/uL, p < 0.05) as well as TMZ (2335 vs. 965 k/uL, p = 0.08) as compared to pts without a response. Conclusions: TMZ is an interesting alternative for metastatic melanoma pts with disease progression on pembro. Our results show a 25% response rate. Further studies in this setting are warranted.