TLDR: TGA wanted more proof of efficacy - Osiris was the sponsor...

TLDR: TGA wanted more proof of efficacy - Osiris was the sponsor & the product was 'Prochymal'

'It is recommended that the application to register Prochymal for the proposed indication be rejected on the grounds of inadequate demonstration of efficacy. The reasons for this recommendation are as follows:

The failure of Study 280 (pivotal study) to demonstrate a statistically significant difference between Prochymal and placebo for the primary efficacy endpoint of complete response of ≥ 28 days duration in the overall ITT population (aGvHD Grade B/C/D): that is, 34.7% (60/173) and 29.9% (26/87), respectively, p = 0.423.

The failure of Study 280 (pivotal study) to demonstrate a statistically significant difference between Prochymal and placebo for the secondary efficacy endpoint of overall survival > 100 days in the overall mITT population (aGvHD Grade B/C/D): that is, 52.1% (85/163) and 50.6% (41/81), respectively, p = 0.780.

The failure of Study 280 (pivotal study) to demonstrate a statistically significant difference between Prochymal and placebo in the secondary efficacy endpoint of overall survival > 180 days in the overall mITT population (aGvHD Grade B/C/D): that is, 34.4% (56/163) and 42.0% (34/81), respectively, p = 0.274.

The lack of a placebo control group in Study 275 (supportive study) making it difficult to interpret the clinical significance of the observed overall response rate at ‘day 28’ of 62.7% (37/59) in a paediatric population aged < 18 years (that is, the primary efficacy endpoint). The importance of including a placebo control group when assessing the efficacy of Prochymal is highlighted by the results from Study 280 for overall response at day 28 which failed to show a statistically significant difference between the two treatment groups: that is, 57.7% (94/163) in the Prochymal group compared with 50.6% (41/81) in the placebo group, p = 0.224.'

https://www.tga.gov.au/sites/default/files/auspar-remestemcel-l-150315.pdf