...a 71-year old male with extensive stage small cell lung cancer harboring CDK12 splice site single nucleotide variation (SNV) mutation….given olaparib, PARP inhibitor, combined with paclitaxel based on his CDK12 mutation...A 6-week follow-up abdomen CT scan revealed a marked shrinkage of metastatic lesions in liver as seen in Fig. 1 (1a: pre-treatment, 1b: 6-week follow-up abdomen CT scans). 40% decrease in the sum of length diameters of lesions was seen which is consistent with partial response per RECIST 1.1 criteria. We observed a deep and durable ongoing partial response for more than five months in this patient receiving olaparib/paclitaxel combination therapy.