Intangible Assets

The gross carrying amounts and net book value of intangible assets were as follows at March 31, 2023:

The gross carrying amounts and net book value of intangible assets were as follows at September 30, 2022:

Amortization expense was approximately $18,000 for the three months ended March 31, 2023 and 2022 and approximately $36,000 for the six months ended March 31, 2023 and 2022.

During the second quarter of fiscal 2023, the Company announced its strategic decision to refocus its drug development efforts on those drug candidates that it believes have the best opportunity to lead to long-term success and shareholder value creation. As part of this strategic decision, the Company has indefinitely ceased development of sabizabulin for prostate cancer and zuclomiphene. As of March 31, 2023, the Company has no current plans that would invest funds in the development of these two assets or that would lead to the Company deriving value from these two assets, which has met the criteria for abandonment under the accounting standards. This resulted in writing off the carrying amount of these two acquired in-process research and development assets and recording an impairment charge of $3.9 million during the quarter ended March 31, 2023.

Goodwill

The carrying amount of goodwill at March 31, 2023 and September 30, 2022 was $6.9 million. There was no change in the balance during the six months ended March 31, 2023 and 2022. The Company’s goodwill is assigned to the Research and Development reporting unit, which had a negative carrying amount as of March 31, 2023.